CN106198255B - Soil body shearing test device and shearing test method under a kind of confining pressure state - Google Patents

Abstract

The invention discloses a soil shear test device and a shear test method under a confining pressure state. The shear test device includes a shearing fixture for clamping a soil sample to be tested, and a device for applying confining pressure to the soil sample to be tested. A pressurizing device and a vertical loading device positioned above the shearing fixture, the shearing fixture comprising an upper clamp and a lower clamp, and the pressurizing device comprising four pressurized blocks; the shearing test method comprises steps: one, sampling; two, shearing Cutting test and image acquisition of soil microstructure: clamping of soil sample and pressurization device, shearing test, dripping of curing liquid, flat cutting of soil sample bottom, soil sample support top, flat cutting of soil sample top, soil in shear joint Taking out the soil sample, subsequent processing of the soil sample in the shear joint, and electron microscope scanning. The invention is reasonable in design, convenient in implementation, low in input cost, short in use time, good in use effect, can simply and quickly complete the soil sample shear test process of the soil shear zone under confining pressure, and can test the soil sample under confining pressure. Accurate analysis of soil microstructure.

Description

Soil shear test device and shear test method under confining pressure state

technical field

The invention belongs to the technical field of geotechnical engineering, in particular to a soil shear test device and a shear test method under confining pressure.

Background technique

In recent years, the transformation of the natural environment by human activities has become more and more intense. Human engineering activities have caused many geological disasters, which have caused great damage to people's lives and properties. Among them, the slope instability induced by human activities is the most serious, and the focus of the study of slope instability is to study the deformation and expansion process of the soil shear zone. The shear zone refers to a strong deformation zone with shear strain developed in the lithosphere or soil mass, and the shear zone developed in the soil mass is a soil shear zone. This deformation zone can be a planar structure (fault) with strain discontinuity, or a ductile shear zone with continuous strain where no geometric discontinuity is seen at the outcrop scale. Studies have shown that the formation of shear bands is closely related to the softening properties of the material itself. Under the action of internal and external geology, the external shape or internal structure of the soil is partially broken, and the deformation gradually concentrates in a relatively narrow shear zone, which further expands to form a continuous sliding surface, and finally forms a landslide. With the in-depth understanding of landslide instability, researchers use various methods to study the expansion process of landslide zone (also called soil shear zone) during the process of landslide instability. Nowadays, the deformation of soil shear zone has become an important subject in the field of rock mechanics.

At present, when conducting shear tests on soil shear zones, the test methods mainly include CT visual scanning method, triaxial test and digital observation method, etc., and the corresponding test instruments mainly include direct shear instrument, triaxial Compression test devices and tensile instruments, etc., but the above test methods and test devices can only solve the local problems of the internal shear zone of rock and soil, and all have complex structures, high test costs, cumbersome test procedures, and operability to varying degrees. The most important thing is that the soil microstructure of the shear zone cannot be analyzed easily, quickly and accurately, so that the influence of the soil microstructure on the macroscopic performance of the soil shear zone cannot be understood. , the link between the soil microstructural properties of the soil shear zone and its macroscopic behavior cannot be established. In addition, it should be noted that most of the existing shear test devices cannot provide confining pressure during the shear test, and cannot better simulate the stress state of the soil.

Contents of the invention

The technical problem to be solved by the present invention is to provide a soil shear test device under confining pressure in view of the deficiencies in the above-mentioned prior art, which has a simple structure, a reasonable design, and is easy to manufacture and use, and has a good effect. The pressure device applies confining pressure, and the soil sample to be tested and the pressure device are synchronously clamped by the upper and lower clamps, which can easily and quickly complete the shear test of the soil sample under the confining pressure state.

In order to solve the above-mentioned technical problems, the technical solution adopted in the present invention is: a soil shear test device under confining pressure, which is characterized in that: it includes a shearing fixture for clamping the tested soil sample, A pressurizing device for applying confining pressure and a vertical loading device positioned above the shearing fixture, the soil sample to be tested is a cylindrical soil sample cut by a sampling ring knife;

The pressurization device includes four pressurization blocks, the four pressurization blocks are arranged on the same horizontal plane and their heights are the same as the height of the tested soil sample, and the inner walls of the four pressurization blocks are Arc-shaped side walls, the soil sample to be tested is clamped in the clamping cavity between the four pressurized blocks; the four pressurized blocks are respectively arranged on the left and right sides of the soil sample to be tested , the left side pressure block, the right side pressure block, the front side pressure block and the rear side pressure block;

The shearing jig includes an upper jig and a lower jig directly below the upper jig, the soil sample to be tested is clamped between the upper jig and the lower jig; the upper jig consists of three The upper clamping blocks arranged to the right are assembled, and the three upper clamping blocks are respectively the upper left clamping block, the upper middle clamping block and the upper right clamping block from left to rear; the lower clamp includes the upper left clamping block The lower left clamping block below the holding block and the lower right clamping block located under the upper right clamping block, there is a middle soil mass between the lower left clamping block and the lower right clamping block for the soil sample to be tested to move downward The moving channel, the bottom of the upper and middle clamping block is provided with an upper pushing boss that can extend into the clamping cavity; the vertical loading device is located directly above the upper and middle clamping block;

The four pressing blocks in the pressing device are clamped between the upper clamp and the lower clamp.

The above-mentioned soil shear test device under confining pressure is characterized in that: the width of the upper clamp and the lower clamp are both larger than the diameter of the tested soil sample, and the width of the upper and middle clamping blocks is smaller than the diameter of the tested soil sample. The diameter of the soil sample.

The above-mentioned soil shear test device under confining pressure is characterized in that: the pressurizing device also includes front connecting bolts and rear connecting bolts, and the front connecting bolts and rear connecting bolts are arranged horizontally And the two are arranged in parallel; the front side connecting bolts and the rear side connecting bolts are respectively located on the front and rear sides of the tested soil sample, and the front side pressure block and the rear side pressure block are respectively located on the left side of the pressure block and the Between the front and rear sides of the right pressure block; the left pressure block, the front side pressure block and the right pressure block are connected as one by the front connecting bolts, the left pressure block, the rear side The pressure block and the right side pressure block are connected as a whole through the rear connection bolts.

The above-mentioned soil shear test device under confining pressure is characterized in that: it also includes a confining pressure measuring device for measuring the pressure applied by the pressure device on the tested soil sample;

The left side pressure block and the right side pressure block are symmetrically arranged, the front side pressure block and the rear side pressure block are symmetrically arranged; the front side connecting bolts and the rear side connecting bolts are connected with the front side The pressing blocks are arranged vertically;

The arc radii of the inner sidewalls of the four pressurized blocks are all smaller than the radii of the tested soil samples.

The above-mentioned soil shear test device under confining pressure is characterized in that: the lower clamp also includes a middle and lower clamping block located between the lower left clamping block and the lower right clamping block, and the lower left clamping block Located directly below the upper left clamping block, the lower right clamping block is located directly below the upper right clamping block, and the lower middle clamping block is located directly below the upper middle clamping block;

The upper left clamping block, the upper middle clamping block, the upper right clamping block, the lower left clamping block, the lower middle clamping block and the lower right clamping block are arranged horizontally; the upper left clamping block and the upper right clamping block The heights of the holding blocks are the same, and the height of the upper middle holding block is not less than the height of the upper left holding block; the heights of the lower left holding block, the lower middle holding block and the lower right holding block are all the same, so The middle and lower clamping blocks include an upper clamping block that can move up and down between the left lower clamping block and the right lower clamping block;

Between the upper left clamping block and the lower left clamping block, between the upper middle clamping block and the upper clamping block, between the upper right clamping block and the lower right clamping block, all are connected by vertical connecting bolts.

The above-mentioned soil shear test device under confining pressure is characterized in that: the lower clamp is a block-type clamp or a boss-type clamp;

The spacer-type clamp also includes three spacers that are installed respectively on the upper parts of the left lower clamping block, the middle lower clamping block and the right lower clamping block and can extend into the clamping cavity. The two pads are spliced to form a round pie-shaped cushion;

The lower left clamping block, the lower middle clamping block, and the lower right clamping block in the boss-type clamp are respectively provided with a lower pushing boss that can extend into the clamping cavity. The lower pushing bosses are assembled to form a cylindrical abutment platform for upward support of the tested soil sample.

At the same time, the present invention also discloses a soil shear test method under confining pressure state with simple method steps, reasonable design, convenient implementation and good use effect. It is characterized in that the method includes the following steps:

Step 1, sampling: using the sampling ring knife to cut the soil sample to be tested from the shear zone of the soil to be tested;

The tested soil sample is cylindrical and its upper and lower surfaces are plane;

Step 2, shear test and soil microstructure image acquisition, the process is as follows:

Step 201, clamping the soil sample and the pressurizing device: horizontally clamp the tested soil sample and the pressurizing device between the upper clamp and the lower clamp, and place the tested soil sample in the pressurizing device for four In the clamping cavity between the two pressurized blocks, the soil sample to be tested is located directly below the middle and upper clamping blocks; at this time, the upper surface of the soil sample to be tested is arranged horizontally, and is tested The upper surface of the soil sample is the surface to be tested;

Step 202, shear test, comprises the following steps:

Step 2021, applying confining pressure to the soil sample: using a pressurizing device to apply a confining pressure to the tested soil sample, and recording the pressure F _encircled by the pressurizing device on the tested soil sample;

Step 2022, vertical loading: using the vertical loading device and applying vertical pressure on the tested soil sample described in step 201 through the middle and upper clamping blocks, so that the tested soil sample undergoes shear failure, and calculates The shear strength of the tested soil sample under the confining pressure state;

After the shear failure occurs, the middle soil mass of the tested soil sample moves down and a shear joint is formed between the middle soil mass and the soil mass on the left and right sides;

During the vertical loading process in step 2022, a pressure device is used to continuously apply confining pressure to the tested soil sample;

Step 203, dripping solidified liquid: drip the pre-prepared solidified liquid into the inner upper part of the two shear joints in step 202, and solidify the soil body on the inner upper part of the shear joint through the solidified liquid, The solidified soil is the solidified soil in the shear joint;

The curing liquid is formed by uniformly mixing epoxy resin, acetone, ethylenediamine and dibutyl phthalate according to the volume ratio of 100: (130-170): (6-8): (1.8-2.2);

Step 204, flat cutting the bottom of the soil sample: cutting the bottom of the tested soil sample flat along the bottom surface of the pressurizing device with the sampling cutting tool;

Step 205, supporting the soil sample: after the soil on the inner side of the shear joint is solidified, use a support tool to support the tested soil sample upward along the pressurizing device until the two shear joints are separated. The solidified soil in the shear joint is moved to the outside of the pressurizing device;

Step 206, flat cutting of the top of the soil sample: cutting the top of the tested soil sample flat along the top surface of the pressurizing device with the sampling cutting tool;

Step 207, taking out the soil sample in the shear joint: from the soil cut in step 206, take out the solidified soil in the shear joint as the soil sample in the shear joint;

Step 208, subsequent processing of the soil sample in the shear joint: cutting, smoothing and polishing the surface to be tested of the soil sample in the shear joint described in step 207, to obtain the observation surface of the soil;

Step 209, electron microscope scanning: Scanning the soil observation surface in step 208 with a scanning electron microscope, and obtaining an electron microscope scanning image of the soil observation surface.

The above method is characterized in that: the pressurizing device in step 2021 also includes a front connecting bolt and a rear connecting bolt, the front connecting bolts and the rear connecting bolts are arranged horizontally and both are arranged in parallel; The front side connecting bolts and the rear side connecting bolts are respectively located on the front and rear sides of the tested soil sample, and the front side pressure block and the rear side pressure block are respectively located on the front and rear sides of the left side pressure block and the right side pressure block. between the sides; the left pressure block, the front pressure block and the right pressure block are connected as one by the front connecting bolts, the left pressure block, the rear pressure block and the right pressure block The blocks are connected as a whole through the rear connecting bolts;

The front connecting bolts and the rear connecting bolts are all arranged on the same water surface and both are located in the middle of the left press block; the front connecting bolts and the rear connecting bolts both include a horizontal screw rod and two left and right The limit nuts that are installed on the horizontal screw rod and respectively limit the pressure block on the left side and the pressure block on the right side; outside;

In step 2021, when the pressure device is used to apply confining pressure to the tested soil sample, the left side pressure block and the right side pressure block are driven by adjusting the two limit nuts on the front side connection bolt and the rear side connection bolt respectively. Synchronously move to the inside horizontally, and then horizontally push the front pressure block and the rear pressure block to move horizontally to the inside;

When the solidified liquid is dripped in step 203, use a dropper to drop the solidified liquid to the inner upper part of the shear seam until the dripped solidified liquid completely covers the upper part of the shear seam; as described in step 203 The height of the solidified soil in the shear joint is 1 mm to 5 mm;

In step 205, when the soil sample to be tested is supported upward along the pressurizing device with the support tool, the height of the support shall not be less than the height of the solidified soil in the shear joint described in step 203.

The above-mentioned method is characterized in that: the shear strength of the tested soil sample calculated in step 202 is the shear strength of the tested soil sample at the position of the surface to be tested described in step 201, and the shear strength of the tested soil sample obtained in step 209 is The scanning electron microscope image of the soil observation surface is the scanning electron microscope image of the soil in the shear joint of the tested soil sample at the position of the surface to be tested described in step 201;

After the flat cutting of the top of the soil sample in step 206 is completed, the upper surface of the tested soil sample is a plane, and at this time the upper surface of the tested soil sample is the next surface to be tested;

After the electron microscope scanning in step 209 is completed, it is necessary to perform a shear test and obtain an image of the soil microstructure on the next surface to be tested of the tested soil sample according to the method described in step 2.

The above method is characterized in that: after the sampling in step 1 is completed, it is necessary to determine the depth of the upper surface of the tested soil sample on the shear zone of the soil to be tested according to the sampling depth of the sampling ring knife;

The number of surfaces to be tested in the soil sample to be tested in step 1 is N, wherein N is a positive integer and N≥2; the N surfaces to be tested are arranged from top to bottom, and the N surfaces to be tested The surface to be tested that is located at the top of the surface is the top surface to be tested, and the N-1 surfaces to be tested except the top surface to be tested among the N surfaces to be tested are all lower surfaces to be tested. noodle;

After the electron microscope scanning in step 209 is completed, step 2 needs to be repeated N-1 times until the shear test of the N surfaces to be tested in the tested soil sample and the acquisition process of the soil microstructure image are completed;

Before any one of the lower surface to be tested in the tested soil sample is subjected to a shear test and the soil microstructure image is acquired, it is required that the upper surface of the tested soil sample described in step 1 be placed on the surface of the soil to be tested. The depth on the shear zone, combined with the shear test on each surface to be tested above the lower surface to be tested and the soil microstructure image acquisition process in step 205 using a support tool to pressurize the tested soil sample along the The height of the top support of the device is determined to determine the depth of the lower surface to be tested on the shear zone of the soil to be tested;

After the shear tests of the N surfaces to be tested in the tested soil sample and the acquisition process of soil microstructure images are completed, the shear strengths at N different depths on the shear zone of the soil to be tested are obtained , and obtain electron microscope scanning images of the soil in the shear seam at N different depths on the shear zone of the soil to be tested.

Compared with the prior art, the present invention has the following advantages:

1. The shear test device adopted is simple in structure and easy to process and manufacture, and the input cost is low. At the same time, the shearing test device is easy to disassemble, light and compact, and easy to mass-produce, and can be used repeatedly.

2. The design of the shearing test device adopted is reasonable, including a shearing fixture, a pressurizing device and a vertical loading device located above the shearing fixture. The pressurizing device includes four pressing blocks; the shearing fixture includes an upper fixture and a lower Fixture, the upper fixture is assembled from three upper clamping blocks arranged from left to right, and the three upper clamping blocks are respectively upper left clamping block, upper middle clamping block and upper right clamping block from left to back; The fixture includes a lower left clamping block and a lower right clamping block, and a movement channel for the middle soil body of the tested soil sample to move downward is reserved between the lower left clamping block and the lower right clamping block.

3. The shearing fixture used is made of plexiglass or resin material, which can visually observe the soil shearing process. Moreover, the shearing jig used is spliced by multiple clamping blocks, which is flexible in use, easy to assemble and replace, and can be easily stored after disassembly, occupying a small space.

4. The shearing fixture used is not limited to the specifications of the tested soil samples, and the tested soil samples are clamped together with the pressurizing device synchronously, which can be applied to the shear test process of the tested soil samples of various specifications, and the structure is simple , Easy installation and low investment cost, easy operation and high practical value during use, no pollution, little impact on the surrounding environment, and the pressure is directly read by the force measuring device of the vertical loading device during the test, which is simple, accurate and effective The invention solves the problem that the shear strength of loose soil is difficult to measure, has broad application prospects, and can realize the soil shear test under confining pressure.

5. The pressure device used includes four pressure blocks, which can easily and quickly construct confining pressure on the tested soil sample, and the pressure is easy to adjust. At the same time, the construction pressure measurement is simple. In actual use, it can easily provide confining pressure for the tested soil sample, so it can better simulate the real stress state of the soil. And the applied pressure is easy to adjust.

6. The shear test device used is easy to operate and has a good effect. The soil sample to be tested and the pressure device are directly clamped by the upper clamp and the lower clamp. There is no need to do any treatment on the soil sample to be tested before the test, which is simple and efficient. Quickly complete the soil sample shear test. Moreover, the shear test device has high test efficiency and accurate test results, and the test process is easy to control.

7. The shear test method adopted is simple in steps, reasonable in design, convenient in implementation, strong in operability, low in test cost, good in use, and flexible in test methods. According to actual needs, the same soil sample to be tested can be tested once. Or multiple shear tests, the shear test results at different heights of the tested soil samples can be obtained accordingly, combined with the results of multiple shear tests, the shear expansion process of the tested soil sample from top to bottom under the confining pressure state can be obtained , creatively proposed a test method for shear band expansion process under confining pressure state, which is easy to implement and effective in use. A shear test process mainly includes pressurization device and soil sample clamping, shear test, solidification solution dripping, flat cutting of the bottom of the soil sample, support of the top of the soil sample, flat cutting of the top of the soil sample, and soil test in the shear joint. The nine steps of sample extraction, subsequent processing of soil samples in shear joints and electron microscope scanning are simple and effective, and the shear test process is easy to control.

8. Two shearing joints are formed after the shearing test with the shearing test device, and then the soil in the shearing joints is solidified with the curing liquid, which is easy to implement and has a good effect, without damaging the internal structure of the soil sample, and solidifies The obtained soil samples in the shear joints can truly reflect the actual structure of the soil in the shear joints under confining pressure.

9. The shear test method adopted can easily and quickly obtain the shear strength at different depths in the shear zone of the tested soil under confining pressure and the microstructure at the shear position, and can be observed and analyzed under macroscopic conditions The soil microstructure at different depths of the tested soil shear zone, the analysis results are accurate and well-founded, and can be used to simulate the expansion process of the soil shear zone. The present invention can measure the shear strength at different depths of the soil shear zone under the confining pressure state, and can study the soil microstructure at different depths of the soil shear zone, so as to obtain the soil shear strength under the confining pressure state. The expansion process of the shear band can be accurately and quickly studied on the change of the microstructure during the expansion process of the shear band of the soil under the confining pressure state. Therefore, the present invention can easily, quickly and accurately analyze the soil microstructure of the shear zone under confining pressure, so as to understand the influence law of the soil microstructure at the particle level on the macroscopic performance of the soil shear zone, Correspondingly, the relationship between the soil microstructure characteristics and the macroscopic performance of the soil shear zone under the confining pressure state is established, and the formation law of the soil shear zone under the confining pressure state can be accurately obtained.

10. It has a wide range of applications and can be effectively applied to the shear test process of the shear zone of loess, soft soil, slippery soil and other soils.

In summary, the present invention is reasonable in design, convenient in implementation, low in input cost, short in time, good in use effect, can simply and quickly complete the soil sample shear test process of the soil shear zone under confining pressure, and can Accurate analysis of soil microstructure under confining pressure.

The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is a schematic structural view of the cutting test device of the present invention.

Fig. 2 is a reference diagram of the use state of the shearing fixture and the pressurizing device of the present invention.

Fig. 2-1 is a schematic structural view of the upper clamping block in the present invention.

Figure 2-2 is the left view of Figure 2-1.

Fig. 3 is a sectional view along line A-A of Fig. 2 .

Fig. 4 is a structural schematic diagram of the pressurizing device of the present invention.

Fig. 5 is a reference diagram of the use state of the pressurizing device of the present invention.

Fig. 6 is a flow chart of the shear test method adopted in the present invention.

Fig. 7-1 is a reference diagram of the test state after the vertical loading device is used to press down the tested soil sample according to the present invention.

Fig. 7-2 is a reference diagram of the test state before the vertical loading device is used to press down the next test surface of the tested soil sample in the present invention.

Fig. 7-3 is a reference diagram of the test state of the present invention after the vertical loading device is used to press down the next surface to be tested of the tested soil sample.

Explanation of reference signs:

1—soil sample to be tested; 2—pressurization device; 2-1—left pressure block;

2-2—right pressure block; 2-3—front pressure block; 2-4—rear pressure block;

2-5—front connecting bolt; 2-6—rear connecting bolt; 3—left upper clamping block;

4—middle and upper clamping block; 4-1—upper push boss; 5—right upper clamping block;

6—left lower clamping block; 7—upper clamping block; 8—right lower clamping block;

9—pad block; 10—vertical connecting bolt; 11—hydraulic jack;

13—block.

Detailed ways

Example 1

As shown in Figure 1, a soil shear test device in a confining pressure state includes a shearing fixture for clamping a tested soil sample 1, a pressurizing device 2 for applying a confining pressure to the tested soil sample 1, and a The vertical loading device above the shearing fixture, the tested soil sample 1 is a cylindrical soil sample cut by a sampling ring knife;

As shown in Fig. 4 and Fig. 5, the pressurizing device 2 includes four pressurizing blocks, and the four pressurizing blocks are all arranged on the same horizontal plane and have the same height as the tested soil sample 1. The inner side walls of each of the pressure blocks are arc-shaped side walls, and the tested soil sample 1 is clamped in the clamping cavity between the four pressure blocks; the four pressure blocks are respectively For the left pressure block 2-1, the right pressure block 2-2, the front pressure block 2-3 and the rear pressure block arranged on the left side, the right side, the front side and the rear side of the tested soil sample 1 Briquetting 2-4;

With reference to Fig. 2, Fig. 2-1, Fig. 2-2 and Fig. 3, the shearing jig includes an upper jig and a lower jig directly below the upper jig, and the tested soil sample 1 is clamped on the upper jig. Between the clamp and the lower clamp; the upper clamp is assembled from three upper clamping blocks arranged from left to right, and the three upper clamping blocks are respectively left upper clamping block 3, In the upper clamping block 4 and the upper right clamping block 5; the lower clamp includes the lower left clamping block 6 positioned below the upper left clamping block 3 and the lower right clamping block 8 positioned below the upper right clamping block 5, the lower left Between the clamping block 6 and the lower right clamping block 8, there is a moving channel for the middle soil body of the tested soil sample 1 to move downward, and the bottom of the middle and upper clamping block 4 is provided with a The upper pushing boss 4-1 in the clamping cavity; the vertical loading device is located directly above the middle and upper clamping block 4;

The four pressing blocks in the pressing device 2 are clamped between the upper clamp and the lower clamp.

In this embodiment, the width of the upper clamp and the lower clamp is larger than the diameter of the tested soil sample 1 , and the width of the upper and middle clamping blocks 4 is smaller than the diameter of the tested soil sample 1 .

In this embodiment, the structure and size of the upper left clamping block 3 and the upper right clamping block 5 are the same and they are arranged symmetrically, and the structure and size of the lower left clamping block 6 and the lower right clamping block 8 are the same. The same and the two are arranged symmetrically.

In this embodiment, the width of the upper pushing boss 4-1 is the same as that of the middle and upper clamping block 4, and its thickness is not less than the vertical downward pressure height of the tested soil sample 1 by the vertical loading device. The front and rear side walls of the upper pushing boss 4-1 are in close contact with the front and rear inner walls of the clamping chamber respectively.

During actual processing, the upper pushing boss 4-1 can be fixed on the bottom of the middle and upper clamping block 4 by gluing, or can be processed into one body with the middle and upper clamping block 4 .

In this embodiment, the vertical loading device is a hydraulic jack 11 or a hydraulic cylinder arranged vertically.

In actual use, the vertical loading device can also adopt other types of loading devices.

In this embodiment, both the upper clamp and the lower clamp are rectangular parallelepiped clamps. Moreover, the length and width of the upper clamp are the same as those of the lower clamp.

And, the width of described upper clamp block 4 is the diameter of tested soil sample 1 In this embodiment, the width of the upper and middle clamping block 4 is 1/2 of the diameter of the tested soil sample 1. In actual use, the width of the upper and middle clamping blocks 4 can be adjusted accordingly according to specific needs.

In this embodiment, the height of the tested soil sample 1 is the same as that of the sampling ring knife, and the height of both is 20mm. Moreover, the diameter of the tested soil sample 1 is the same as the inner diameter of the sampling ring cutter.

Wherein, the diameter of the sampling ring cutter is 61.8mm.

In this embodiment, the height of the sampling ring knife is 20mm.

In this embodiment, the lower clamp further includes a middle and lower clamping block located between the lower left clamping block 6 and the lower right clamping block 8, the lower left clamping block 6 is located directly below the upper left clamping block 3, The lower right clamping block 8 is located directly below the upper right clamping block 5, and the middle and lower clamping block is located directly below the upper middle clamping block 4;

The upper left clamping block 3, the upper middle clamping block 4, the upper right clamping block 5, the lower left clamping block 6, the lower middle clamping block and the lower right clamping block 8 are arranged horizontally; the upper left clamping The height of the clamping block 3 and the upper right clamping block 5 is the same, and the height of the upper middle clamping block 4 is not less than the height of the upper left clamping block 3; the lower left clamping block 6, the lower middle clamping block and the right The heights of the lower clamping blocks 8 are all the same, and the middle and lower clamping blocks include an upper clamping block 7 that can move up and down between the lower left clamping block 6 and the lower right clamping block 8;

Between the upper left clamping block 3 and the lower left clamping block 6, between the upper middle clamping block 4 and the upper clamping block 7, and between the upper right clamping block 5 and the lower right clamping block 8, all are connected vertically Bolt 10 is connected.

In this embodiment, between the upper left clamping block 3 and the lower left clamping block 6, between the upper middle clamping block 4 and the upper clamping block 7, and between the upper right clamping block 5 and the lower right clamping block 8 Both are connected by two vertical connecting bolts 10 at the front and rear. The two front and rear vertical connecting bolts 10 are respectively located on the front and rear sides of the pressurizing device 2 .

And, the front and rear sides of the upper left clamping block 3, the lower left clamping block 6, the upper middle clamping block 4, the upper clamping block 7, the upper right clamping block 5 and the lower right clamping block 8 are provided with a The bolt installation hole that vertical connection bolt 10 is installed.

In actual use, the middle and upper clamping block 4 can move up and down between the left upper clamping block 3 and the right upper clamping block 5 .

In this embodiment, the height of the upper middle clamping block 4 is greater than the height of the upper left clamping block 3, and the height of the upper middle clamping block 4 is greater than the height of the upper left clamping block 3 by Hmm, wherein H=2～ 8.

In this embodiment, the middle and lower clamping blocks further include a padding block 9 directly under the upper clamping block 7 .

And, the height of the lower left clamping block 6 and the lower right clamping block 8 is the same, the height of the upper clamping block 7 is less than the height of the lower left clamping block 6, and the height of the upper clamping block 7 and the padding block 9 The sum of the heights is identical with the height of the lower left clamping block 6.

In this embodiment, the upper left clamping block 3, the upper middle clamping block 4, the upper right clamping block 5, the lower left clamping block 6, the lower middle clamping block and the lower right clamping block 8 are all cuboids; The bottom surfaces of the upper left clamping block 3, the upper middle clamping block 4 and the upper right clamping block 5 are all horizontal planes, and the tops of the lower left clamping block 6, the lower middle clamping block and the lower right clamping block 8 All surfaces are horizontal.

During actual processing, the upper left clamping block 3 and the lower left clamping block 6 have the same width, the upper middle clamping block 4 has the same width as the lower middle clamping block, and the upper right clamping block 5 and the lower right clamping block have the same width. The clamping blocks 8 have the same width.

In this embodiment, the length and width of the upper left clamping block 3, the upper middle clamping block 4, the upper right clamping block 5, the lower left clamping block 6, the lower middle clamping block and the lower right clamping block 8 are the same. Moreover, the length, width and height of the upper clamping block 7 and the padding block 9 are the same.

During actual processing, the upper left clamping block 3, the upper middle clamping block 4, the upper right clamping block 5, the lower left clamping block 6, the upper clamping block 7, the lower right clamping block 8 and the pad loading block 9 are all Clear plexiglass block.

As shown in Figures 4 and 5, the pressurizing device 2 also includes a front connecting bolt 2-5 and a rear connecting bolt 2-6, and the front connecting bolt 2-5 and the rear connecting bolt 2-6 Both are arranged horizontally and both are arranged in parallel; the front connecting bolts 2-5 and the rear connecting bolts 2-6 are respectively located on the front and rear sides of the tested soil sample 1, and the front pressure block 2-3 and the rear side pressure block 2-4 are respectively located between the front and rear sides of the left side pressure block 2-1 and the right side pressure block 2-2; the left side pressure block 2-1, the front side pressure block The block 2-3 and the right side pressure block 2-2 are connected as one by the front side connecting bolt 2-5, and the left side pressure block 2-1, the rear side pressure block 2-4 and the right side pressure block 2-2 is connected as a whole by rear side connecting bolt 2-6.

At the same time, the soil shear test device under the confining pressure state of the present invention also includes a confining pressure measuring device for measuring the pressure applied by the pressurizing device 2 on the tested soil sample 1;

The left pressure block 2-1 and the right pressure block 2-2 are symmetrically arranged, and the front side pressure block 2-3 and the rear side pressure block 2-4 are symmetrically arranged; the front side The connecting bolts 2-5 and the rear connecting bolts 2-6 are arranged vertically with the front pressure block 2-3;

The arc radii of the inner sidewalls of the four pressurized blocks are all smaller than the radius of the tested soil sample 1 .

In this embodiment, the confining pressure measuring device is a dynamometer.

In actual use, the confining pressure measuring device can also use a spring with a known elastic coefficient, and measure the construction pressure of the pressurizing device 2 according to the deformation length of the spring during the construction of the confining pressure.

In this embodiment, the confining pressure measuring device further includes two force gauges for respectively measuring the pressure exerted by the left pressing block 2-1 and the right pressing block 2-2.

A soil shear test method under a confining pressure state as shown in Figure 6 comprises the following steps:

Step 1, sampling: using the sampling ring knife to cut the tested soil sample 1 from the shear zone of the soil to be tested;

The tested soil sample 1 is cylindrical and its upper and lower surfaces are plane;

Step 2, shear test and soil microstructure image acquisition, the process is as follows:

Step 201, Clamping of the soil sample and the pressurizing device: Both the tested soil sample 1 and the pressurizing device 2 are horizontally clamped between the upper clamp and the lower clamp, and the tested soil sample 1 is placed in the pressurized In the clamping cavity between the four pressurized blocks in the device 2, and the soil sample 1 to be tested is located directly below the middle and upper clamping block 4; at this time, the upper surface of the soil sample 1 to be tested It is arranged horizontally, and the upper surface of the tested soil sample 1 is the surface to be tested;

Step 202, shear test, comprises the following steps:

Step 2021, applying confining pressure to the soil sample: using the pressurizing device 2 to apply confining pressure to the tested soil sample 1, and recording the pressure F _encircled by the pressurizing device 2 on the tested soil sample 1;

Step 2022, vertical loading: using the vertical loading device and applying vertical pressure to the tested soil sample 1 in step 201 through the middle and upper clamping blocks 4, so that the tested soil sample 1 undergoes shear failure, and Calculate the shear strength of the tested soil sample 1 under the applied confining pressure state;

After the shear failure occurs, the middle soil mass of the tested soil sample 1 moves down and a shear joint is formed between the middle soil mass and the soil mass on the left and right sides;

During the vertical loading process in step 2022, the pressure device 2 is used to continuously apply confining pressure to the tested soil sample 1;

Step 203, dripping solidified liquid: drip the pre-prepared solidified liquid into the inner upper part of the two shear joints in step 202, and solidify the soil body on the inner upper part of the shear joint through the solidified liquid, The solidified soil is the solidified soil in the shear joint;

The curing solution is formed by uniformly mixing epoxy resin, acetone, ethylenediamine and dibutyl phthalate according to a volume ratio of 100:150:7:2;

Step 204, flat cutting the bottom of the soil sample: cutting the bottom of the tested soil sample 1 flatly along the bottom surface of the pressurizing device 2 with the sampling cutting tool;

Step 205, supporting the soil sample: after the soil on the inner side and upper part of the shear joint is solidified, use a support tool to support the tested soil sample 1 upward along the pressurizing device 2 until the two shear joints The solidified soil in the shear joint is all moved to the outside of the pressurizing device 2;

Step 206, flat cutting of the top of the soil sample: cutting the top of the tested soil sample 1 along the top surface of the pressurizing device 2 with the sampling cutting tool;

Step 207, taking out the soil sample in the shear joint: from the soil cut in step 206, take out the solidified soil in the shear joint as the soil sample in the shear joint;

Step 208, subsequent processing of the soil sample in the shear joint: cutting, smoothing and polishing the surface to be tested of the soil sample in the shear joint described in step 207, to obtain the observation surface of the soil;

Step 209, electron microscope scanning: Scanning the soil observation surface in step 208 with a scanning electron microscope, and obtaining an electron microscope scanning image of the soil observation surface.

Wherein, the surface to be tested of the soil sample in the shear joint is its upper surface. Therefore, in step 208, the subsequent processing of the soil sample in the shear joint is performed, and the upper surface of the soil sample in the shear joint is cut, smoothed and polished.

In this embodiment, the front connecting bolts 2-5 and the rear connecting bolts 2-6 are arranged on the same water surface and both are located in the middle of the left pressure block 2-1; the front connecting bolts 2-5 and the rear side connecting bolt 2-6 both include a horizontal screw and two left and right are respectively installed on the horizontal screw and respectively limit the left pressure block 2-1 and the right pressure block 2-2 The limit nut; the two limit nuts are respectively located on the outside of the left pressure block 2-1 and the right pressure block 2-2;

In step 2021, when the pressurizing device 2 is used to apply confining pressure to the tested soil sample 1, the two limit nuts on the front connecting bolt 2-5 and the rear connecting bolt 2-6 are respectively adjusted to drive the left clamping nut. The pressing block 2-1 and the right pressing block 2-2 move horizontally to the inside synchronously, and then horizontally push the front pressing block 2-3 and the rear pressing block 2-4 to move horizontally to the inside.

Therefore, by adjusting the two limit nuts on the front connecting bolt 2-5 and the rear connecting bolt 2-6, the construction pressure of the pressurizing device 2 can be adjusted easily and quickly.

In addition, there is an adjustment gap between two adjacent left and right pressing blocks in the pressing device 2 .

In this embodiment, when performing electron microscope scanning in step 209, an energy spectrometer is also required to obtain energy spectrum diagrams of a plurality of observation surfaces of the soil.

In this way, according to the energy spectrum diagram of the soil observation surface, the material of each soil particle in the electron microscope scanning image of the soil observation surface is determined.

In this embodiment, the jacking tool described in step 205 is a jacking jack or a jacking cylinder.

In this embodiment, when the soil sample in the shear joint is taken out in step 207, it is necessary to take out the soil sample in the shear joint from the two shear joints in step 205; and, from each When the soil sample in the shear joint is taken out from the shear joint, one or more pieces of solidified soil in the shear joint are taken out from the shear joint as the soil in the shear joint. sample.

Moreover, after the soil sample in the shear joint is taken out in step 207, the soil sample in the shear joint needs to be dried or air-dried.

In this embodiment, an oven is used to dry the soil sample in the shear joint. In actual use, it can also be air-dried naturally.

Before the drying is finished, the soil sample in the shear joint needs to be weighed every 8 minutes to 12 minutes until the soil sample in the shear joint is weighed three times in a row compared with the last weighing result. The drying process ends when the mass change of each is no more than 0.02g.

In this embodiment, the soil sample in the shear joint is baked in an oven for one hour, and then taken out and weighed every 10 minutes until the change in the weight of the three weighings does not exceed 0.02g, and the shear joint is completed. Drying process of inner soil samples. After the soil sample in the shearing joint is dried, the internal residual moisture can be discharged, which facilitates the rapid completion of the internal curing process of the soil sample in the shearing joint. At the same time, it can effectively keep the internal solid structure and pores of the soil sample in the shear joint from being damaged.

In this embodiment, before the shear test is performed in step 202, the cushion block 9 is drawn out horizontally, so that the lower part of the upper clamping block 7 is suspended in the air.

After the clamping of the soil sample and the pressurizing device in step 201 is completed, place the shearing fixture holding the pressurizing device 2 and the tested soil sample 1 horizontally on the horizontal workbench, and the vertical loading device is located at on the horizontal workbench.

In this embodiment, when calculating the shear strength of the tested soil sample 1 in step 2022, according to the formula Calculation.

In the formula (1), F is the maximum vertical pressure that the tested soil sample 1 can withstand under the state of applying confining pressure in step 2022, and A is the vertical pressure applied to the tested soil sample 1 in step 201 in step 202. The shear area of the tested soil sample 1 during the stress process. Wherein, A is the contact area between the middle and upper clamping block 4 and the tested soil sample 1 .

In this embodiment, when the solidifying liquid is dripped in step 203, the solidifying liquid is dripped to the inner upper part of the shearing seam drop by drop with a dropper until the dripping solidifying liquid completely covers the upper part of the shearing seam. The preparation process of the solidification liquid is simple and effective, and has the advantages of low viscosity, good thermosetting performance and the like.

In actual use, the volume ratios of epoxy resin, acetone, ethylenediamine and dibutyl phthalate in the curing liquid can be adjusted accordingly according to specific needs.

In this embodiment, before the curing solution is dripped in step 203, the upper clamp is removed from the soil sample 1 to be tested.

In this embodiment, after the solidification solution is dripped in in step 203 and before the bottom of the soil sample is flat-cut in step 204, it needs to stand still until the soil body at the inner upper part of the shearing joint is completely solidified.

And, it is left to stand under normal temperature conditions, and the normal temperature conditions are under the temperature conditions of 20°C to 30°C.

In actual use, the epoxy resins in the curing liquid are all bisphenol A type epoxy resins, bisphenol F type epoxy resins, multifunctional novolak epoxy resins, novolac epoxy resins or brominated epoxy resins. One or any mixture of epoxy resins. In this embodiment, the epoxy resin in the curing liquid is bisphenol A epoxy resin.

In this embodiment, after the vertical loading device is used in step 2022 and the vertical pressure is applied to the tested soil sample 1 in step 201 through the middle and upper clamping block 4, the middle and upper clamping block 4 is vertically Move down by hmm, where h≤H.

In this embodiment, sampling is carried out in step 1, and the sampling method adopted is the conventional sampling method of the sampling ring knife (ie, the ring knife sampling method), and the sampling process is simple and convenient to implement.

When actually cutting the soil sample, the sampling ring knife can be arranged vertically or obliquely. Therefore, the sampling direction of the sampling ring knife can be adjusted according to specific needs.

In this embodiment, the height of the solidified soil in the shear joint described in step 203 is 1 mm to 5 mm;

In step 205, when the tested soil sample 1 is supported upward along the pressurizing device 2 with the support tool, the height of the support is not less than the height of the solidified soil in the shear joint described in step 203.

In actual use, when the tested soil sample 1 is supported upward along the pressurizing device 2 in step 205 with a support tool, the height of the support is 3mm-6mm.

In this embodiment, the height of the abutment is 5mm.

In this embodiment, when taking out the solidified soil in the shearing joint from the cut soil in step 207, use a cotton swab to stick out the solidified soil in the shearing joint.

In this embodiment, the shear strength of the tested soil sample 1 calculated in step 202 is the shear strength of the tested soil sample 1 at the position of the surface to be tested described in step 201, and the shear strength of the tested soil sample 1 obtained in step 209 is The scanning electron microscope image of the soil observation surface is the scanning electron microscope image of the soil in the shear joint of the tested soil sample 1 at the position of the surface to be tested described in step 201;

After the flat cutting of the top of the soil sample in step 206 is completed, the upper surface of the tested soil sample 1 is a plane, and at this time the upper surface of the tested soil sample 1 is the next surface to be tested;

After the electron microscope scanning is completed in step 209, it is necessary to perform a shear test and obtain an image of the soil microstructure on the next surface to be tested of the tested soil sample 1 according to the method described in step 2.

In this embodiment, in conjunction with Fig. 7-1, Fig. 7-2 and Fig. 7-3, after the sampling in step 1 is completed, it is also necessary to test the upper surface of the tested soil sample 1 at the sampling depth according to the sampling depth of the sampling ring knife. Determine the depth on the shear zone of the soil to be tested;

The number of surfaces to be tested in the soil sample 1 to be tested in step 1 is N, wherein N is a positive integer and N≥2; the N surfaces to be tested are arranged from top to bottom, and the N surfaces to be tested The surface to be tested located at the top of the test surface is the top surface to be tested, and the N-1 surfaces to be tested except the top surface to be tested among the N surfaces to be tested are all lower surfaces to be tested. test surface;

After the electron microscope scanning in step 209 is completed, step 2 needs to be repeated N-1 times until the shear test of the N surfaces to be tested in the tested soil sample 1 and the image acquisition process of the soil microstructure are completed;

Before any one of the lower surface to be tested in the tested soil sample 1 is subjected to a shear test and the soil microstructure image is acquired, it is necessary to perform the test on the upper surface of the tested soil sample 1 according to the step 1. The depth on the soil shear zone, combined with the shear test on each surface to be tested above the lower surface to be tested and the soil microstructure image acquisition process in step 205 using a support tool to test the soil sample 1 Determine the depth of the lower surface to be tested on the shear zone of the soil to be tested along the height of the top of the pressurization device 2;

After the shear tests of the N surfaces to be tested in the tested soil sample 1 and the acquisition process of the soil microstructure images are completed, the sheared values at N different depths on the shear zone of the soil to be tested are obtained. strength, and obtain electron microscope scanning images of the soil in the shear joint at N different depths on the shear zone of the soil to be tested.

In this embodiment, N=3-8.

In actual use, the value of N can be adjusted accordingly according to specific needs.

And, when carrying out the shear test and soil microstructure image acquisition on the top surface to be tested, the test state before the shear test in step 202 is shown in Fig. 3 for details; the test state after the shear test is completed in step 202, See Figure 7-1 for details. When performing a shear test and soil microstructure image acquisition on the next surface to be tested located below the top surface to be tested and adjacent to the top surface to be tested, the test state before the shear test in step 202 , see Figure 7-2 for details; see Figure 7-3 for details of the test state after the shear test in step 202.

In actual use, the lower clamp is a pad-type clamp or a boss-type clamp;

The spacer-type clamp also includes three spacers that are installed on the upper parts of the left lower clamping block 6, the middle lower clamping block and the right lower clamping block 8 and can extend into the clamping cavity. 13. The three pads 13 are spliced to form a circular cake-shaped cushion, and the diameter of the circular cake-shaped cushion is the same as the diameter of the tested soil sample 1. See Figure 7-1, Figure 7-2 and Figure 7-1 for details. 7-3;

In the boss-type clamp, the upper parts of the left lower clamping block 6, the middle lower clamping block and the right lower clamping block 8 are respectively provided with a lower pushing boss that can extend into the clamping cavity, and three The lower pushing bosses are assembled to form a cylindrical abutment platform for supporting the tested soil sample 1 upward, and the diameter of the cylindrical abutment platform is the same as that of the tested soil sample 1 .

In this embodiment, the lower clamp is a pad type clamp.

Therefore, during the shear test and the soil microstructure image acquisition process for any one of the lower surface to be tested in the tested soil sample 1, when the soil sample and the pressurizing device are clamped in step 201, it is also necessary to The lower left clamping block 6, the middle and lower clamping block (specifically the upper clamping block 7) and the upper part of the right lower clamping block 8 are all provided with a cushion block 13 extending into the inside of the clamping cavity , the thickness of the cushion block 13 is the same as the distance between the bottom surface of the tested soil sample 1 and the bottom surface of the pressurizing device 2 at this time; 7) splicing with the cushion block 13 placed on the upper part of the lower right clamping block 8 to form a circular pie-shaped cushion layer, and the circular cake-shaped cushion layer extends into the clamping cavity.

In actual use, it is also possible to set an upper part of the left lower clamping block 6, the middle and lower clamping block (specifically, the upper clamping block 7) and the right lower clamping block 8, which can extend into the clamping cavity. The heights of the three lower pushing bosses are not less than the distance between the bottom surface of the tested soil sample 1 and the bottom surface of the pressurizing device 2 at this time, and the three lower pushing bosses The platform is assembled to form a cylindrical abutment platform for supporting the tested soil sample 1 upward.

In this embodiment, when the tested soil sample 1 is supported upward along the pressurizing device 2 in step 205, the height of the tested soil sample 1 needs to be recorded.

In this embodiment, when the surface to be tested is cut, ground and polished in step 208, the cutting machine is used to cut the surface first, and then the automatic grinding machine is used for fine grinding, and then the abrasive is used for fine grinding. Then polish on the polishing machine.

When performing fine grinding, grind the surface to be tested after fine grinding on a frosted glass plate, hold the soil sample in the shearing seam for circular motion during grinding, and use water as lubricant and cooling agent in the grinding process. agent.

In this embodiment, after taking out the soil sample in the shearing seam, stick the soil sample in the shearing seam on the glass slide; The soil sample is put into an automatic grinding machine, and the surface to be tested of the soil sample in the shear joint is finely ground, and after fine grinding, the surface to be tested has no voids, cracks and scratches; Then, the soil sample in the shearing seam after fine grinding is used as lubricant and coolant with water, and finely ground on a frosted glass plate with emery abrasive, and the soil sample in the shearing seam is treated The surface to be tested is all shiny and no scratches are checked under oblique light, and the fine grinding is stopped; finally, the soil sample in the shear joint after fine grinding is placed on a polishing machine and polished with a polishing solution, and the polishing time is 2 -5 minutes.

In this embodiment, when performing electron microscope scanning in step 209, continuous scanning is performed from left to right or from right to left.

When actually performing electron microscope scanning, the soil sample in the shear joint is placed under a scanning electron microscope for scanning. The number of scans needs to be determined according to the size of the surface to be tested.

In the actual operation process, the data processing device is a PC, a notebook or a PDA. In this embodiment, the data processing device is a PC.

In this embodiment, after the electron microscope scanning is completed in step 209, when analyzing the soil microstructure of the soil sample in the shear joint, the data processing device calls Image-Pro Plus software to scan the electron microscope image to process.

When actually analyzing the microstructure, first import the entire electron microscope scanning image of the surface to be tested into the Image-Pro Plus software, and use the Image-Pro Plus software to observe and analyze the laws of soil particle cementation, separation distance and particle edge.

And, after adopting Image-Pro Plus software to observe and analyze the soil electron microscope scanning images of the shear joints at N different depths on the soil shear zone to be tested, the soil shear zone to be tested can be easily obtained. The soil microstructure at different depths above, by analyzing the electron microscope scanning images of the soil in the shear joints at different depths, it can be obtained that the fracture of microscopic soil particles on the shear zone of the soil to be tested is from top to bottom. , dislocation, and changes, so that the expansion process of the shear band of the soil to be tested can be directly and quickly analyzed.

Example 2

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:170:6:2.2.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 3

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:170:8:1.8.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 4

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:130:8:1.8.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 5

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:140:7:1.8.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 6

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:140:7:1.8.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 7

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:130:6:1.8.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 8

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:130:6:2.2.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

Example 9

In this embodiment, the shear test device of the soil shear zone is the same as that in Embodiment 1.

In the present embodiment, the shear test method of the soil shear band adopted is different from Embodiment 1 in that: the curing liquid described in step 203 is made of epoxy resin, acetone, ethylenediamine and dibutyl phthalate The esters are uniformly mixed according to the volume ratio of 100:170:8:2.2.

In this embodiment, the rest of the steps of the shear test method of the soil shear zone are the same as those in Embodiment 1.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any way. All simple modifications, changes and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still belong to the technical aspects of the present invention. within the scope of protection of the scheme.

Claims (10)

1. A soil body shear test device under a confining pressure state, is characterized in that: comprise the shear fixture that is clamped to tested soil sample (1), the pressurization that applies confining pressure to tested soil sample (1) device (2) and a vertical loading device positioned above the shearing fixture, the tested soil sample (1) is a cylindrical soil sample cut by a sampling ring knife; The pressurization device (2) includes four pressurization blocks, the four pressurization blocks are all arranged on the same level and their heights are the same as the height of the tested soil sample (1). The inner side walls of the blocks are all arc-shaped side walls, and the tested soil sample (1) is clamped in the clamping cavity between the four pressurized blocks; the four pressurized blocks are respectively arranged in the The left side pressure block (2-1), the right side pressure block (2-2), the front side pressure block (2-3 ) and rear pressure block (2-4); The shearing fixture includes an upper fixture and a lower fixture directly below the upper fixture, and the tested soil sample (1) is clamped between the upper fixture and the lower fixture; the upper fixture consists of three Assembled from two upper clamping blocks arranged from left to right, the three upper clamping blocks are respectively upper left clamping block (3), upper middle clamping block (4) and upper right clamping block from left to rear (5); The lower clamp includes a lower left clamping block (6) located below the upper left clamping block (3) and a lower right clamping block (8) located below the upper right clamping block (5), the lower left clamping Between the holding block (6) and the lower right holding block (8), there is a moving channel for the middle soil mass of the tested soil sample (1) to move downward, and the bottom of the middle and upper holding block (4) is set There is an upper pushing boss (4-1) that can extend into the clamping cavity; the vertical loading device is located directly above the middle and upper clamping block (4); The four pressing blocks in the pressing device (2) are clamped between the upper clamp and the lower clamp. 2. according to claim 1 under a kind of soil body shear test device under the confining pressure state, it is characterized in that: the width of described upper clamp and described lower clamp is all greater than the diameter of tested soil sample (1), so The width of the middle and upper clamping block (4) is smaller than the diameter of the tested soil sample (1). 3. The soil shear test device under a kind of confining pressure state according to claim 1 or 2, characterized in that: said pressurizing device (2) also includes front side connecting bolts (2-5) and rear side Connecting bolts (2-6), the front connecting bolts (2-5) and the rear connecting bolts (2-6) are arranged horizontally and in parallel; the front connecting bolts (2-5 ) and the rear connecting bolts (2-6) are respectively located on the front and rear sides of the tested soil sample (1), and the front pressure block (2-3) and the rear side pressure block (2-4) are respectively located at Between the front and rear sides of the left side pressure block (2-1) and the right side pressure block (2-2); the left side pressure block (2-1), the front side pressure block (2-3 ) and the right pressure block (2-2) are connected as a whole through the front side connecting bolts (2-5), and the left side pressure block (2-1), the rear side pressure block (2-4) and The right pressure block (2-2) is connected as a whole through the rear connecting bolts (2-6). 4. according to claim 3 under a kind of soil body shear test device under the confining pressure state, it is characterized in that: also comprise the pressure that pressurizing device (2) is applied on the tested soil sample (1) to measure Confining pressure measuring device; The left pressing block (2-1) and the right pressing block (2-2) are arranged symmetrically, and the front pressing block (2-3) and the rear pressing block (2-4) Arranged symmetrically; the front connecting bolts (2-5) and the rear connecting bolts (2-6) are arranged perpendicular to the front pressure block (2-3); The arc radii of the inner sidewalls of the four pressurized blocks are all smaller than the radius of the tested soil sample (1). 5. According to claim 1 or 2 described soil shear test device under a kind of confining pressure state, it is characterized in that: said lower fixture also comprises clamping block (6) and right lower clamping block (8) ), the lower left clamping block (6) is located directly below the upper left clamping block (3), and the lower right clamping block (8) is located at the upper right clamping block (5) directly below, the middle and lower clamping block is located directly below the middle and upper clamping block (4); The upper left clamping block (3), the upper middle clamping block (4), the upper right clamping block (5), the lower left clamping block (6), the lower middle clamping block and the lower right clamping block (8 ) are arranged horizontally; the height of the upper left clamping block (3) and the upper right clamping block (5) is the same, and the height of the upper middle clamping block (4) is not less than the height of the upper left clamping block (3) ; The heights of the lower left clamping block (6), the lower middle clamping block and the lower right clamping block (8) are all the same, and the lower middle clamping block includes a clamping block that can be placed between the lower left clamping block (6) and the lower right clamping block (8). The upper clamping block (7) that moves up and down between the lower right clamping blocks (8); Between the upper left clamping block (3) and the lower left clamping block (6), between the upper middle clamping block (4) and the upper clamping block (7), and between the upper right clamping block (5) and the lower right clamping block The holding blocks (8) are all connected by vertical connecting bolts (10). 6. The soil shear test device under confining pressure according to claim 5, characterized in that: the lower clamp is a pad type clamp or a boss type clamp; The block-type clamp also includes three pads installed on the upper parts of the left lower clamping block (6), the middle lower clamping block and the right lower clamping block (8) and can extend into the clamping cavity Inner pad (13), three described pads (13) are spliced to form a round pie-shaped pad; The lower left clamping block (6), the middle lower clamping block and the upper right lower clamping block (8) of the boss-type clamp are respectively provided with a lower pushing protrusion that can extend into the clamping cavity. The three lower pushing bosses are assembled to form a cylindrical abutment platform for upward support of the tested soil sample (1). 7. a method utilizing the soil shear test device as claimed in claim 1 to carry out the soil shear test under the confining pressure state, is characterized in that, the method may further comprise the steps: Step 1, sampling: using the sampling ring knife to cut the tested soil sample (1) from the shear zone of the soil to be tested; The tested soil sample (1) is cylindrical and its upper and lower surfaces are plane; Step 2, shear test and soil microstructure image acquisition, the process is as follows: Step 201, Clamping of the soil sample and the pressurizing device: horizontally clamp the tested soil sample (1) and the pressurizing device (2) between the upper clamp and the lower clamp, and make the tested soil sample (1) in the clamping cavity between the four pressurizing blocks in the pressurizing device (2), and the tested soil sample (1) is located directly below the middle and upper clamping blocks (4); , the upper surface of the tested soil sample (1) is arranged horizontally, and the upper surface of the tested soil sample (1) is the surface to be tested; Step 202, shear test, comprises the following steps: Step 2021, applying confining pressure to the soil sample: using the pressurizing device (2) to apply confining pressure to the tested soil sample (1), and _confining the pressure F exerted by the pressurizing device (2) on the tested soil sample (1) record; Step 2022, vertical loading: using the vertical loading device and applying vertical pressure to the tested soil sample (1) in step 201 through the middle and upper clamping blocks (4), so that the tested soil sample (1) Shear failure occurs, and the shear strength of the tested soil sample (1) is calculated under the state of applying confining pressure; After the shear failure occurs, the soil in the middle of the tested soil sample (1) moves down and a shear joint is formed between the soil in the middle and the soil on the left and right sides; During the vertical loading process in step 2022, the pressure device (2) is used to continuously apply confining pressure to the tested soil sample (1); Step 203, dripping solidified liquid: drip the pre-prepared solidified liquid into the inner upper part of the two shear joints in step 202, and solidify the soil body on the inner upper part of the shear joint through the solidified liquid, The solidified soil is the solidified soil in the shear joint; The curing liquid is formed by uniformly mixing epoxy resin, acetone, ethylenediamine and dibutyl phthalate according to the volume ratio of 100: (130-170): (6-8): (1.8-2.2); Step 204, flat cutting the bottom of the soil sample: cutting the bottom of the tested soil sample (1) flat along the bottom surface of the pressurizing device (2) with the sampling cutting tool; Step 205, supporting the soil sample: after the soil on the upper part of the inner side of the shear joint is solidified, use a supporting tool to support the tested soil sample (1) upward along the pressurizing device (2) until the two The solidified soil in the shear joints of the shear joints is all moved to the outside of the pressurizing device (2); Step 206, flat cutting of the top of the soil sample: cutting the top of the tested soil sample (1) flat along the top surface of the pressurizing device (2) with the sampling cutting tool; Step 207, taking out the soil sample in the shear joint: from the soil cut in step 206, take out the solidified soil in the shear joint as the soil sample in the shear joint; Step 208, subsequent processing of the soil sample in the shear joint: cutting, smoothing and polishing the surface to be tested of the soil sample in the shear joint described in step 207, to obtain the observation surface of the soil; Step 209, electron microscope scanning: Scanning the soil observation surface in step 208 with a scanning electron microscope, and obtaining an electron microscope scanning image of the soil observation surface. 8. The method according to claim 7, characterized in that: said pressurizing device (2) in step 2021 also includes front side connecting bolts (2-5) and rear side connecting bolts (2-6), said The front connecting bolts (2-5) and the rear connecting bolts (2-6) are arranged horizontally and in parallel; the front connecting bolts (2-5) and the rear connecting bolts (2-6 ) are respectively located on the front and rear sides of the tested soil sample (1), and the front side pressure block (2-3) and the rear side pressure block (2-4) are respectively located on the left side pressure block (2-1) and between the front and rear sides of the right press block (2-2); the left press block (2-1), the front press block (2-3) and the right press block (2- 2) Connected as a whole through the front side connecting bolts (2-5), the left pressure block (2-1), the rear side pressure block (2-4) and the right pressure block (2-2) Connected as a whole through the rear connecting bolts (2-6); The front connecting bolts (2-5) and the rear connecting bolts (2-6) are all arranged on the same water surface and both are located in the middle of the left pressure block (2-1); the front connecting Both the bolt (2-5) and the rear side connecting bolt (2-6) include a horizontal screw rod and the left and right two are respectively installed on the horizontal screw rod and pressurize the left side pressure block (2-1) and the right side respectively. block (2-2) to limit the limit nut; the two limit nuts are respectively located on the outside of the left pressure block (2-1) and the right pressure block (2-2); In step 2021, when the pressurizing device (2) is used to apply confining pressure to the tested soil sample (1), by adjusting the two bolts on the front side connecting bolt (2-5) and the rear side connecting bolt (2-6) respectively The above limit nut drives the left pressure block (2-1) and the right pressure block (2-2) to move horizontally inward synchronously, and then horizontally pushes the front pressure block (2-3) and the rear pressure block Blocks (2-4) move horizontally to the inside; When the solidified liquid is dripped in step 203, use a dropper to drop the solidified liquid to the inner upper part of the shear seam until the dripped solidified liquid completely covers the upper part of the shear seam; as described in step 203 The height of the solidified soil in the shear joint is 1 mm to 5 mm; In step 205, when the tested soil sample (1) is supported upward along the pressurizing device (2) with the support tool, the height of the support is not less than the height of the solidified soil in the shear joint described in step 203. 9. according to the method described in claim 7 or 8, it is characterized in that: the shear strength of the tested soil sample (1) calculated in step 202 is tested at the position of the surface to be tested described in step 201 The shear strength of the soil sample (1), the scanning electron microscope image of the soil observation surface obtained in step 209 is in the shear seam of the tested soil sample (1) at the position of the surface to be tested described in step 201 Electron microscope scanning image of soil; After the flat cutting of the top of the soil sample in step 206 is completed, the upper surface of the tested soil sample (1) is a plane, and at this time the upper surface of the tested soil sample (1) is the next described surface to be tested; After the electron microscope scanning is completed in step 209, it is necessary to perform a shear test and obtain an image of the soil microstructure on the next surface to be tested of the tested soil sample (1) according to the method described in step 2. 10. according to the described method of claim 9, it is characterized in that: after sampling in the step 1 is finished, also need according to the sampling depth of sampling ring cutter, to the soil sample (1) upper surface to be tested in described soil body to be tested shear The depth on the cutting strip is determined; The number of surfaces to be tested in the soil sample to be tested (1) described in step 1 is N, wherein N is a positive integer and N≥2; the N surfaces to be tested are arranged from top to bottom and the N Among the surfaces to be tested, the surface to be tested located at the top is the top surface to be tested, and the N-1 surfaces to be tested except the top surface to be tested among the N surfaces to be tested are all The lower surface to be tested; After the electron microscope scanning is completed in step 209, step 2 needs to be repeated N-1 times until the shear test of the N surfaces to be tested in the tested soil sample (1) and the image acquisition process of the soil microstructure are completed; Before any one of the lower surface to be tested in the tested soil sample (1) is subjected to the shear test and the acquisition of the soil microstructure image, it is necessary to obtain the upper surface of the tested soil sample (1) according to step 1. The depth on the shear zone of the soil to be tested, combined with the shear test on each surface to be tested above the lower surface to be tested and the use of a supporting tool in step 205 in the soil microstructure image acquisition process will be Determining the depth of the lower surface to be tested on the shear zone of the soil to be tested by the height of the top support of the test soil sample (1) along the pressurizing device (2); After the shear tests of the N surfaces to be tested in the tested soil sample (1) and the acquisition process of soil microstructure images are all completed, the images at N different depths on the shear zone of the soil to be tested are obtained. shear strength, and obtain electron microscope scanning images of the soil in the shear seam at N different depths on the shear zone of the soil to be tested.