CN118292416B - Soil body complex stress state sensing feeler and testing method - Google Patents

Abstract

The invention discloses a soil body complex stress state sensing feeler-probe and a testing method, the feeler gauge consists of a multifunctional probe, a probe rod, a penetrating device, a hydraulic transmission device and a data acquisition and analysis system. The method is characterized in that: the multifunctional probe comprises a conical head, a friction sleeve, a wing rod, an auxiliary rod and a bidirectional hydraulic cylinder. One end of the wing rod is hinged to the head of the multifunctional probe, the other end of the wing rod is hinged to the auxiliary rod, the auxiliary rod is used for controlling the rotation, the unfolding and the retraction of the wing rod, and soil bodies are sheared under different angles. The invention realizes the perception of the complex stress state of the soil body by changing the angle of the wing rod, is particularly suitable for the horizontal stress loss of the stratum and the weakening test identification of the bearing performance of the soil body caused by the excavation unloading environment of the underground engineering, has the characteristics of simplicity, convenience, rapidness, strong functionality and the like, improves the in-situ test efficiency and the identification precision of the complex stress state of the underground engineering, and has wide application value.

Description

A soil complex stress state sensing probe and testing method

Technical Field

The invention belongs to the technical field of in-situ testing of geotechnical engineering investigations, and in particular relates to a digital soil complex stress state sensing probe.

Background Art

Compared with indoor tests, geotechnical in-situ testing technology has the characteristics of no sampling and little disturbance, and is an important method for obtaining the physical and mechanical parameters of geotechnical bodies. Commonly used in-situ test probes include static penetration tester (CPT), flat shovel dilatometer (DMT), lateral pressure tester (PMT), T-type and ball-type full-flow penetration tester, etc. In general, the development progress of new probes is slow and cannot meet the needs of complex engineering construction. The necessity of accelerating the development of new probes is becoming increasingly prominent.

Conventional test probes have their own applicable conditions and are limited to specific strata. For example, static penetration is suitable for clay, silt and sand, but not for super soft soil, and is not very sensitive to changes in lateral force; T-shaped and spherical penetration are suitable for super soft soil, but due to the large size of the probe, it is difficult to penetrate into clay and sand in normal plastic state, and can only give a single parameter and cannot fully interpret the engineering properties of the soil; flat shovel lateral expansion and lateral pressure tests have lateral loading characteristics and a high degree of recognition of the horizontal stress state of the soil, but there are disadvantages such as discontinuous testing and complex operation techniques.

In recent years, the development of urban underground space has been continuously strengthened. Due to the unloading of tunnels and foundation pits, the stress state of the strata has changed, especially the change of the horizontal stress state, which has led to frequent engineering accidents. Inaccurate identification of the stress state of the soil in the unloading environment is one of the important reasons for the occurrence of disasters, and conventional penetration instruments do not perform well in identifying the anisotropy of the stress state of the soil. The combined application of multiple in-situ testing technologies is costly, and a single hole cannot be used multiple times. Moreover, because different testing methods have different principles and precisions, the method of converting various parameters from various testing methods is not only inefficient, but also difficult to guarantee reliability. Therefore, in order to better meet the multifunctional testing needs of geotechnical engineering surveys, it is urgent to invent a soil complex stress state sensing penetration instrument.

Summary of the invention

The purpose of the present invention is to provide a soil complex stress state sensing probe to solve the defects of the existing in-situ testing probe mentioned in the background technology.

To achieve the above object, the present invention adopts the following technical solution:

A soil complex stress state sensing probe, comprising:

A multifunctional probe, the multifunctional probe comprises a cone head, a friction sleeve, a wing rod, an auxiliary rod and a bidirectional hydraulic cylinder. One end of the wing rod is hinged to the head of the multifunctional probe, and the other end is hinged to the auxiliary rod, which is controlled by the auxiliary rod to rotate, expand and retract, and is used to shear soil at different angles;

A probe rod, the probe rod is connected to the upper end of the multifunctional probe through a thread, and an oil pipe and a sensor cable are passed through the probe rod;

A penetration device, wherein the multifunctional probe and the probe rod are clamped and driven by the penetration device to penetrate the soil to perform in-situ testing;

A hydraulic transmission device, wherein the oil pipe connects the hydraulic transmission device and a bidirectional hydraulic cylinder inside the multifunctional probe;

The data acquisition and analysis system, the sensor cable transmits the signal collected by the sensor inside the multi-function probe back to the data acquisition and analysis system.

Furthermore, the bidirectional hydraulic cylinder is installed on the cavity wall of the tail of the multifunctional probe; the cylinder piston rod chamber is grooved on the tube wall, and a closed linear module is arranged at the groove. The inner side of the slide seat of the closed linear module is fixedly connected to the head of the cylinder piston rod, and the outer side of the slide seat of the closed linear module is hinged to the auxiliary rod, and the reciprocating motion of the piston rod drives the auxiliary rod to move, further controlling the deployment and retraction of the wing rod.

Furthermore, the hydraulic transmission device includes a power element and a control element. The power element includes an oil pump; the control element includes a flow valve, a pressure valve, and a directional valve.

Furthermore, the penetration device may be a drilling rig, a crawler vehicle, a jack or other back pressure device.

Furthermore, the multifunctional probe is provided with a pore water pressure sensor, a wing rod resistance sensor, a cone head pressure sensor, and a casing friction resistance sensor. In addition to being able to measure the pore water pressure, cone head resistance, and side wall friction resistance during continuous penetration into the soil, the multifunctional probe can also calculate the force of the wing rod during continuous penetration into the soil or rotary shearing of the soil at a specific depth based on the cylinder thrust and the pressure measured by the wing rod resistance sensor and the deployment angle of the wing rod.

Furthermore, the cone head is detachable and replaceable, and two types of options are provided: a conventional conical cone head and a pointed-mouth round-bottom cone head.

Furthermore, the wing rod is detachable and replaceable, providing 5 types of options: full-length rod, half-length rod, half-length rod with blade, ball rod, and flat shovel rod. On the basis of the full-length rod, half-length rod, and half-length rod with blade, 5 types of cross-sectional rods are further provided: cylindrical, reduced-diameter cylindrical, elliptical, rectangular, and diamond-shaped. Other types of wing rods can also be replaced. The size of the wing rod can be adjusted according to soil conditions.

Furthermore, the multifunctional probe may also adopt the following structural form: wing rods are installed on both sides, and grooves are opened on both sides of the rear end tube, and the wing rods on both sides are hinged to the cylinder piston rod to improve the structural strength and prevent the cylinder piston rod from being subjected to radial force.

Furthermore, according to the power and waterproof requirements, the hydraulic cylinder can be replaced by an electric cylinder, a pneumatic cylinder, or an electric hydraulic cylinder.

The present invention also proposes a testing method for the soil complex stress state sensing probe, which includes the following testing steps:

(1) Clean the site, bring in and position the penetration device, and adjust the support level;

(2) Pass the sensor cable and oil pipe on the multi-function probe through the probe rod and connect them to the data acquisition and analysis system and the hydraulic transmission device respectively. Connect the multi-function probe and the probe rod and install them on the penetration device. Set the test parameters and debug the system to make it operate normally. Adjust the initial deployment angle of the wing rod so that it can penetrate the soil at this angle later;

(3) Start the penetration device and start the penetration test. During the penetration process, real-time data on pore water pressure, cone head resistance, side wall friction, wing rod resistance, and cylinder thrust are collected. The collected data is processed and recorded by the data acquisition and analysis system and displayed in real-time in the form of a curve;

(4) Stop penetration at the depth where the pore pressure dissipation test is required, and record the dissipation process of the pore pressure over time in real time until the pore pressure approaches the hydrostatic pressure; stop penetration at the depth where the wing rod rotation shear test is required, rotate the wing rod to expand or retract it, and record the wing rod resistance and cylinder thrust at different wing rod expansion angles in real time;

(5) After the multi-function probe reaches the predetermined penetration depth, the test is stopped, the angle of the retracted wing rod is rotated, and the probe is retracted by lifting the rod under the drive of the penetration device.

Compared with the prior art, the present invention has the following beneficial effects: according to the stress measured by the cylinder thrust and the wing bar resistance sensor and in combination with the deployment angle of the wing bar, the force on the wing bar can be calculated, the in-situ characteristic parameters of the soil can be interpreted, and the complex stress state of the soil can be identified.

The wing rod and cone head have multiple combinations and can be assembled and replaced according to different formation properties and application scenarios. The cone and pointed round bottom cone head selection expands the application range of the instrument from soft soil to sandy soil, and the wing rods of different structural types improve the test accuracy of the instrument for special soils such as marine super soft soil.

The angle of the wing bar can be fixed in advance before the penetration of the probe according to the formation properties, and can be driven by oil pressure after reaching a specific depth to continuously rotate and shear the soil. The wing bar rotation shear test can effectively identify the horizontal stress state and rotational stress state of pile foundation horizontal bearing, foundation pit excavation unloading, tunnel side penetration, etc.

The present invention overcomes the defect that the existing in-situ test probe cannot independently and accurately identify the changes in the complex stress state of the soil. Through the penetration resistance of the wing rods at different angles and the mechanical effect of the wing rods rotating and shearing the soil at a specified depth, it realizes the rapid, accurate and continuous identification of the changes in the anisotropic complex stress state of the soil, greatly improving the efficiency and accuracy of in-situ testing of underground engineering.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the internal structure principle of the multifunctional probe of the present invention,

FIG2 is a schematic diagram of the overall structure of the soil complex stress state sensing probe according to the present invention.

FIG3 is a schematic diagram of an alternative replaceable cone head of the present invention,

FIG4 is a schematic diagram of an alternative type of replaceable wing rod of the present invention,

FIG5 is a schematic diagram of an alternative cross-sectional shape of a replaceable wing bar according to the present invention,

FIG6 is a schematic diagram of an alternative structural form of the multifunctional probe of the present invention,

FIG. 7 is a flow chart of a testing method of a soil complex stress state sensing probe according to the present invention.

In the figure: 1-cone head; 2-wing rod; 3-auxiliary rod; 4-friction casing; 5-bidirectional hydraulic cylinder; 6-sealed linear module; 7-pore water pressure sensor; 8-wing rod resistance sensor; 9-cone head pressure sensor; 10-casing friction resistance sensor; 11-oil pipe; 12-sensor cable; 13-multi-function probe; 14-probe rod; 15-penetration device; 16-hydraulic transmission device; 17-data acquisition and analysis system.

DETAILED DESCRIPTION

The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

As shown in Figure 1-2, a soil complex stress state sensing probe includes:

The multifunctional probe 13 includes a cone head 1, a wing rod 2, an auxiliary rod 3, a friction sleeve 4 and a bidirectional hydraulic cylinder 5. One end of the wing rod 2 is hinged to the head of the multifunctional probe 13, and the other end is hinged to the auxiliary rod 3. The auxiliary rod 3 controls the rotation, expansion and retraction, and is used to shear the soil at different angles;

A probe rod 14, wherein the probe rod 14 is connected to the upper end of the multifunctional probe 13 through a thread, and an oil pipe 11 and a sensor cable 12 are passed through the probe rod 14;

A penetration device 15, wherein the multifunctional probe 13 and the probe rod 14 are clamped and driven by the penetration device 15 to penetrate into the soil to perform in-situ testing;

A hydraulic transmission device 16, wherein the oil pipe 11 connects the hydraulic transmission device 16 and the bidirectional hydraulic cylinder 5 inside the multifunctional probe 13;

The sensor cable 12 transmits the signal collected by the sensor inside the multifunctional probe 13 back to the data collection and analysis system 17 .

As a preferred embodiment of the present invention, the bidirectional hydraulic oil cylinder 5 in the multifunctional probe 13 is installed on the cavity wall of the tail of the multifunctional probe 13 through the head flange to serve as a water seal; the oil cylinder piston rod chamber is grooved at the pipe wall, and a closed linear module 6 is arranged at the groove to serve as a mud seal to prevent water and soil contact from affecting the oil pipe 11 and the sensor cable 12. The inner side of the slide seat of the closed linear module 6 is fixedly connected to the head of the oil cylinder piston rod, and the outer side of the slide seat of the closed linear module 6 is hinged to the auxiliary rod 3, and the auxiliary rod 3 is driven to move through the reciprocating motion of the piston rod, and the deployment and retraction of the wing rod 2 are further controlled.

As a preferred embodiment of the present invention, the hydraulic transmission device 16 includes a power element and a control element. The power element includes an oil pump; the control element includes a flow valve, a pressure valve, and a directional valve.

As a preferred embodiment of the present invention, the penetration device 15 can be a drilling rig, a crawler vehicle, a jack or other back pressure devices.

As a preferred embodiment of the present invention, the multifunctional probe is provided with a pore water pressure sensor 7, a wing rod resistance sensor 8, a cone head pressure sensor 9, and a casing friction sensor 10. In addition to being able to measure the pore water pressure, cone head resistance, and side wall friction resistance during continuous penetration into the soil, the multifunctional probe 13 can also calculate the force of the wing rod 2 during continuous penetration into the soil or rotary shearing of the soil at a specific depth based on the cylinder thrust and the pressure measured by the wing rod resistance sensor 8 and the deployment angle of the wing rod 2.

As a preferred embodiment of the present invention, the cone head 1 is detachable and replaceable, and provides two types of options: a conical cone head and a pointed-mouth round-bottom cone head, as shown in FIG3 .

As a preferred embodiment of the present invention, the wing rod 2 is detachable and replaceable, and provides five types of selection: full-length rod, half-length rod, half-length rod with blade, ball rod, and flat shovel rod, as shown in Figure 4. On the basis of the full-length rod, half-length rod, and half-length rod with blade, five types of cross-sectional shapes of rods are further provided: cylindrical, reduced-diameter cylindrical, elliptical, rectangular, and diamond-shaped, and other types of wing rods can also be replaced. The embodiments of the five types of full-length rods with cross-sectional shapes are shown in Figure 5. According to the soil conditions, the size of the wing rod can be adjusted, from sand, silt to clay, and the size of the wing rod can be reduced in sequence when replaced.

As a preferred embodiment of the present invention, the multifunctional probe 13 may also adopt the structure shown in FIG. 7 , and its function and principle are the same as those of the structure shown in FIG. 1 , but wing rods are added on both sides, and grooves are opened on both sides of the rear end tube, and the wing rods on both sides are hinged to the cylinder piston rod to improve the structural strength and prevent the cylinder piston rod from being subjected to radial force.

According to the geological conditions of the survey site, taking into account the cylinder thrust and waterproof level requirements, the bidirectional hydraulic cylinder 5 can be replaced by an electric cylinder, a pneumatic cylinder or an electric hydraulic cylinder, and the hydraulic transmission device can be replaced by corresponding electric or pneumatic system components.

The present invention also proposes a testing method for the soil complex stress state sensing probe, as shown in FIG7 , comprising the following testing steps:

(1) Clean the site, move the penetration device 15 into the site, position it, and adjust the support level.

(2) Pass the oil pipe 11 and sensor cable 12 on the multifunctional probe 13 through the probe rod 14 and connect them to the hydraulic transmission device 16 and the data acquisition and analysis system 17 respectively. Connect the multifunctional probe 13 and the probe rod 14 and install them on the penetration device 15. Set the test parameters and debug the system to make it operate normally. Adjust the initial deployment angle of the wing bar 2 so that it can penetrate the soil at this angle later.

(3) Start the penetration device 15 and start the penetration test. During the penetration process, the pore water pressure, cone head resistance, side wall friction resistance, wing rod resistance, and cylinder thrust data are collected in real time. The collected data is processed and recorded by the data acquisition and analysis system 17 and displayed in real time in the form of a curve.

(4) Stop penetration at the depth where the wing rod rotation shear test is required, rotate to expand or retract the wing rod 2, and record the wing rod resistance and cylinder thrust at different expansion angles of the wing rod 2 in real time.

(5) After the multifunctional probe 13 penetrates to the predetermined depth, the test is stopped, the wing rod 2 is rotated to retract the angle, and the probe is retracted under the drive of the penetration device 15.

The soil complex stress state sensing probe and testing method of the present invention have the following beneficial effects:

The complex stress state sensing probe for soil of the present invention overcomes the defect that the existing in-situ testing probes cannot independently and accurately identify the changes in the complex stress state of soil. Through the penetration resistance of wing rods at different angles and the mechanical effect of wing rod rotation shearing soil at a specified depth, it realizes rapid, accurate and continuous identification of the changes in the anisotropic complex stress state of soil, greatly improving the efficiency and accuracy of in-situ testing of underground engineering and having wide application value.

Obviously, the above description is only a preferred embodiment of the present invention, rather than limiting the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims (6)

1. A soil complex stress state sensing probe, characterized by comprising: The multifunctional probe includes a cone head, a friction sleeve, a wing rod, an auxiliary rod and a bidirectional hydraulic cylinder. One end of the wing rod is hinged to the head of the multifunctional probe, and the other end is hinged to the auxiliary rod. The auxiliary rod controls the rotation, expansion and retraction, and is used to shear the soil at different angles. The probe rod is connected to the upper end of the multifunctional probe through a thread, and the probe rod is provided with an oil pipe and a sensor cable. The multifunctional probe and the probe rod are clamped and driven by the penetration device to penetrate the soil to perform in-situ testing. A hydraulic transmission device, wherein the oil pipe connects the hydraulic transmission device and a bidirectional hydraulic cylinder inside the multifunctional probe; A data acquisition and analysis system, wherein the sensor cable transmits the signal collected by the sensor inside the multifunctional probe back to the data acquisition and analysis system; The bidirectional hydraulic cylinder is installed on the cavity wall of the tail of the multifunctional probe, the cylinder piston rod chamber is grooved at the tube wall, a closed linear module is arranged at the groove, the inner side of the slide seat of the closed linear module is fixedly connected to the head of the cylinder piston rod, and the outer side of the slide seat of the closed linear module is hinged to the auxiliary rod, and the auxiliary rod is driven to move by the reciprocating motion of the piston rod to control the deployment and retraction of the wing rod; The hydraulic transmission device includes a power element and a control element, wherein the power element includes an oil pump; the control element includes a flow valve, a pressure valve, and a directional valve; The multifunctional probe is provided with one or more of a pore water pressure sensor, a wing rod resistance sensor, a cone head pressure sensor, and a casing friction resistance sensor. The multifunctional probe adopts the following structure: wing rods are installed on both sides, and grooves are opened on both sides of the rear end tube, and the wing rods on both sides are hinged to the cylinder piston rod. 2. The soil complex stress state sensing probe according to claim 1 is characterized in that the penetration device is set to be one of a drilling rig, a crawler vehicle, and a jack. 3. The soil complex stress state sensing probe according to claim 1 is characterized in that the cone head is configured as a detachable and replaceable structure, including two types of options: a conical cone head and a pointed round-bottom cone head. 4. The soil complex stress state sensing probe according to claim 1 is characterized in that the wing rod is configured as a detachable and replaceable structure, including five types of options: full-length rod, half-length rod, half-length rod with blade, ball rod, and flat shovel rod. 5. The soil complex stress state sensing probe according to claim 1 is characterized in that: The hydraulic cylinder can be replaced by one of an electric cylinder, a pneumatic cylinder, and an electric hydraulic cylinder. 6. A method for testing a soil complex stress state sensing probe, characterized in that the soil complex stress state sensing probe according to any one of claims 1 to 5 is used, and the testing method comprises the following testing steps: (1) Clean the site, bring in the penetration device, position it, and adjust the support level. (2) Pass the sensor cable and oil pipe on the multi-function probe through the probe rod and connect them to the data acquisition and analysis system and the hydraulic transmission device respectively. Connect the multi-function probe and the probe rod and install them on the penetration device. Set the test parameters and debug the system to make it operate normally. Adjust the initial deployment angle of the wing rod so that it can penetrate the soil at this angle later. (3) Start the penetration device and start the penetration test. During the penetration process, real-time data on pore water pressure, cone head resistance, side wall friction resistance, wing rod resistance, and cylinder thrust are collected. The collected data are processed and recorded by the data acquisition and analysis system and displayed in real-time in the form of curves. (4) Stop penetration at the depth where the wing rod rotation shear test is required, rotate the wing rod to expand or retract it, and record the wing rod resistance and cylinder thrust at different wing rod expansion angles in real time. (5) After the multi-function probe reaches the predetermined penetration depth, the test is stopped, the angle of the retracted wing rod is rotated, and the probe is retracted by lifting the rod under the drive of the penetration device.