CN110261235B - Fracture surrounding rock anchoring performance damage testing device and testing method - Google Patents

Abstract

The invention provides a test device and a test method for the damage of the anchorage performance of cracked surrounding rocks, and relates to the technical field of bolt support performance tests. A servo hydraulic cylinder is fixed on the frame. The servo hydraulic cylinder includes an upper servo hydraulic cylinder and a side servo hydraulic cylinder. The servo hydraulic cylinder pressurizes the damaged fracture specimen or the complete rock specimen. The connection frame and the loading frame are fixedly connected. The end of the connecting frame and the end of the annular oil cylinder are provided with anchor rod fixing fixtures. One end of the test anchor rod is fixed by the anchor rod fixing fixture, and the other end is set in the damaged crack specimen. The ground stress is simulated by the servo hydraulic cylinder, and the annular The oil cylinder pulls the anchor rod. The device and method can complete the simulation test of the influence of surrounding rock damage on the anchoring force of the bolt, test the damage evolution law of the anchoring performance of the surrounding rock with different cracks, and can also test the mechanical performance of the bolt (cable).

Description

Anchorage damage test device and test method for fracture surrounding rock

technical field

The invention relates to the technical field of bolt support performance testing, in particular to an anchorage performance damage testing device for cracked surrounding rocks, and a method for using the device for testing.

Background technique

The discontinuity of surrounding rock is a common problem faced in geotechnical engineering construction. In a specific geological environment, the natural rock mass is subjected to the action of geological stress, resulting in the formation of various through or non-through joint fissures inside the rock mass. This fissure structure affects the physical and mechanical properties and characteristics of the surrounding rock, and causes safety problems often encountered in mining, tunnels, and underground spaces. Numerous theoretical studies and engineering practices have shown that the instability and failure of surrounding rock in roadways are mostly related to the expansion and penetration of internal joints and fissures. The bolt anchoring technology can significantly improve the mechanical properties of the surrounding rock of the fracture, limit the expansion and penetration of the internal fracture of the surrounding rock, and enhance the integrity and stability of the surrounding rock. various fields of engineering.

For coal mine roadways, currently most of the roadways are anchored with bolts. However, due to the complex geomechanical environment where the surrounding rock of the fracture is located, and the many factors such as the process equipment involved in the anchoring project, the research on the anchorage control mechanism of the surrounding rock of the fracture lags far behind. In engineering practice, anchoring engineering design mostly relies on empirical and semi-experienced methods. First, the surrounding rock of the fracture is mostly discontinuous, and its mechanical parameters are significantly different from those of the complete rock specimen, and the mechanical properties of the rock mass are weakened, and the specific parameters are not easy to determine, which brings difficulties to numerical simulation and theoretical analysis; secondly , The detection of surrounding rock fissures at the site of the support project is complex and difficult, and it is difficult to carry out long-term monitoring by using ultrasonic surrounding rock fissure detectors or double-ended plugging borehole water injection methods. The characteristics and laws of the interaction with the anchor are not easy to spy. Finally, the current research on the mechanical properties of fractured rock mass is mainly based on experimental research. Scholars at home and abroad have carried out a lot of research on jointed rock mass in the form of single fracture, double fracture and multiple fractures, and have achieved a series of results; The test of anchoring force is mostly destructive pull-out test at this stage, and most of the tests do not consider the actual surrounding rock structure and ground stress and other environmental factors; the test equipment for the anchoring performance of surrounding rock can generally apply surface force to the rock specimen to simulate the ground. However, it is difficult to quantitatively study the influence of primary or secondary cracks in the surrounding rock on the anchoring force of bolts, and the actual situation of elastoplastic changes in rock mass under high stress state, and then failure occurs.

After the construction of anchoring drilling, the rock wall of the drilling is affected by drilling, stress redistribution and mining action will also produce cracks. Under the influence of secondary cracks and primary joint cracks, the anchoring performance of the surrounding rock will be affected to a certain extent. Among them, what is the influence degree of the surrounding rock fissures, how the anchoring surrounding rock fissures expand, and what is the bearing performance of the fissured rock mass. The solution of these problems requires scientific and reasonable experimental research. Therefore, based on the needs of the above research, on the basis of considering the effect of surrounding rock cracks on the damage of the anchoring performance of the bolt and the effect of the bolt on the anchoring control effect of the cracked rock mass, the anchoring performance testing device and the testing method of the anchoring performance of the bolt are further improved. is very necessary. The key to the experimental research is to reasonably simulate the large-scale fractured surrounding rock, rather than prefabricated fractured rock specimens. Two methods can be used. To generate cracks, the loading method can be used to simulate the in-situ stress and mining stress, so that the surrounding rock around the borehole enters the plastic zone. Therefore, it is necessary to further improve the test device and test method for the damage of cracked surrounding rock anchorage performance on the basis of considering the influence of surrounding rock damage cracks on the anchoring of bolts.

SUMMARY OF THE INVENTION

In order to realize the simulation test of the influence of surrounding rock damage on the anchoring force of the bolt, and to better study the anchoring performance of the bolt, the present invention provides a device and method for testing the damage of the anchorage performance of the surrounding rock with cracks. The specific technical scheme is as follows.

Anchorage damage test device for fracture surrounding rock, including servo hydraulic cylinder, connecting frame, loading frame, annular oil cylinder and anchor rod fixing fixture, the servo hydraulic cylinder is fixed on the loading frame, and the servo hydraulic cylinder includes the upper servo hydraulic cylinder and the side servo hydraulic cylinder ;The damaged crack specimen is placed in the loading frame, and the servo hydraulic cylinder pressurizes the damaged crack specimen; the connecting frame and the loading frame are fixedly connected, and the annular oil cylinder is arranged at the end of the connecting frame; the end of the annular oil cylinder is provided with anchor rod fixing fixture ; One end of the test anchor is fixed by the anchor fixing fixture, and the other side is set in the damaged crack specimen.

Preferably, one or more boreholes are arranged on the damaged crack specimen, and a static breaking agent is arranged in the borehole; the test bolt is fixed in the middle of the damaged crack specimen.

It is further preferred that the damage crack test piece is made by a test piece mold, and the test piece mold includes a plurality of mold plates, and the mold plates are fixed by nuts and insertion holes; fit.

It is also preferable that a blocking clip is provided on one side of the contact end face of the loading frame and the connecting frame, and the connecting frame and the loading frame are arranged on the fixed base; on the rod.

It is also preferred that the upper servo hydraulic cylinder is provided with at least two respectively for loading the damaged crack specimen, and two corresponding side servo hydraulic cylinders are respectively provided on both sides of the loading frame section where the upper servo hydraulic cylinder is located.

A test method for the damage test of the anchorage performance of the surrounding rock of a fracture, using the above-mentioned device for testing the damage of the anchorage performance of the surrounding rock of the fracture to carry out the test, and the steps include:

Step A _1. Make a simulated test piece of similar material or take a field rock to make a simulated test piece;

Step B _1. Delineate the crack direction and crack range of the simulated specimen, and drill the specimen;

Step C _1. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the static crushing agent into the drilled hole to make damage cracks;

Step D _1. Observing the position, direction and scope of the damaged cracks, grinding the surface of the specimen to obtain a damaged crack specimen, drilling an anchor hole on the damaged crack specimen, and combining the test bolt with the bolt anchoring agent. Put the bolt into the hole;

Step E _1. After the bolt anchoring agent is anchored, the damaged crack specimen is taken out from the specimen mold and placed in the loading frame, the end of the anchor rod is fixed by the anchor rod fixing fixture, and the damaged crack specimen is loaded by the servo hydraulic cylinder;

Step F ₁ . Pulling the bolt through the annular oil cylinder, recording the change of the pulling force of the bolt during the test, as well as the damage form, crack width and number of cracks of the damaged crack specimen.

A test method for testing the damage of cracked surrounding rock anchorage performance, using the above-mentioned test device for impacting the anchorage performance by the damage of surrounding rock cracks in the anchoring section of a bolt, the steps include:

Step A _2. Make a simulated test piece of similar material or take a field rock to make a simulated test piece;

Step B _2. Drilling a bolt hole on the simulated specimen, and putting the test bolt and the bolt anchoring agent into the bolt hole together;

Step _C2 . After the bolt anchoring agent is anchored, the crack direction and crack range of the simulated test piece are delineated, and the test piece is drilled;

Step D _2. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the static crushing agent into the drilled hole to make damage cracks;

Step E _2. Observing the position, direction and scope of the damage crack, after grinding the surface of the test piece to obtain the damage crack test piece, take out the damage crack test piece from the test piece mold and put it into the loading frame, and fix the anchor rod with the anchor rod fixing fixture The end of the damaged crack is loaded by the servo hydraulic cylinder;

Step F ₂ . Pulling the bolt through the annular oil cylinder, recording the change of the pulling force of the bolt during the test, as well as the damage form, crack width and number of cracks of the damaged crack specimen.

A test method for testing the damage of cracked surrounding rock anchorage performance, using the above-mentioned test device for impacting the anchorage performance by the damage of surrounding rock cracks in the anchoring section of a bolt, the steps include:

Step A3. _Make a simulated test piece of similar material or take a field rock to make a simulated test piece;

Step B _3. Drilling a bolt hole on the simulated specimen, and putting the test bolt and the bolt anchoring agent into the bolt hole together;

Step C3. After the bolt anchoring agent is anchored, the crack direction and crack range _of the simulated specimen are delineated, and the specimen is drilled;

Step D _3. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the time-delayed static crushing agent into the drilled hole;

Step E _3. Take out from the test piece mold, after grinding the surface of the test piece, put the simulated test piece into the loading frame, fix the end of the anchor rod with the anchor rod fixing fixture, and load the damaged crack test piece through the servo hydraulic cylinder ;

Step F ₃ . Pulling the bolt through the annular oil cylinder, delaying the action of the static crushing agent during the pulling process, simulating the crack expansion of the specimen within the delimited range to obtain a damaged crack specimen; recording the bolt pulling force during the test process Variations, as well as the damage pattern, crack width, and number of cracks in the damage-cracked specimen.

It is also preferred that the damaged crack specimen is covered with a rubber film on the surface before being placed in the loading frame; the diameter of the hole into which the static crushing agent is placed is less than or equal to 20 mm; the damaged crack specimen also includes a borehole side wall damage crack specimen. , after drilling, load the drilled specimen through the servo hydraulic cylinder, and the side wall of the drilled hole produces damage cracks to obtain the specimen with damaged cracks on the sidewall of the drilled hole.

It is further preferred that the damage crack specimen is made of similar materials, the similar material is concrete or gypsum, the damage crack is one or more, and the damage crack is perpendicular to the specimen or oblique to the specimen.

The beneficial effects of the present invention include:

(1) The damage test device for the anchorage performance of the surrounding rock of the fracture, loads the damaged fracture surrounding rock specimen through the servo hydraulic cylinder and the loading frame, thereby simulating the in-situ stress conditions of the surrounding rock anchored, and this method can also be used to increase the load to cause cracking The surrounding rock of the side wall of the drilling hole is obtained to obtain the surrounding rock specimens damaged by the cracks in the side wall area of the anchoring hole; the annular oil cylinder is used for loading, so as to simulate the force of the bolt along the direction of the bolt, and then the device can be used for different damage forms and different damage patterns. Anchorage pull-out test of fractured surrounding rock under the condition of damage degree. Ordinary bolt pull test generally does not consider surrounding rock damage and ground stress conditions. This device provides an innovative platform for indoor testing of bolt mechanical properties and experimental research on bolt anchoring performance.

(2) By making specimens of damaged cracks surrounding rock, and then simulating and studying the influence of damage cracks in the anchoring section on the anchoring performance during bolt anchoring, setting small holes and using static breakers can accurately manufacture appropriate damage crack specimens. The specimen mold further facilitates the production of damaged fracture specimens, and can also prevent large volume deformation of the rock specimen, which in turn affects the installation of subsequent specimens on the testing machine, and even the specimen mold can be used to simulate the fracture surrounding rock specimen. The setting of the blocking clip can effectively fix the specimen, and can also fix one end of the bolt during the tensile performance test of the ordinary bolt; the displacement protection device can prevent the bolt from excessively stretching, record the displacement, and Protect the test device.

(3) In this method, the pull-out test of the bolt is carried out after making the damaged crack specimen. On the basis of making full use of the structure of the device, the anchoring performance of the anchoring section of the bolt can be simulated by adjusting the loading of the servo hydraulic cylinder to simulate different in-situ stress conditions. By setting different damage cracks to test the anchorage performance, the influence of damage cracks on the anchorage force and anchorage bearing performance is studied, and the influence of the development process of cracks on the anchorage performance of the bolt is studied by the time-delayed static crushing agent. Changes of anchoring force, crack propagation and fracture characteristics of surrounding rock before and after anchoring were compared to study the control effect of bolt on surrounding rock cracks.

Description of drawings

Fig. 1 is a schematic diagram of the structure of the fracture surrounding rock anchorage damage testing device;

Fig. 2 is the front view of test apparatus;

Fig. 3 is the top view of the test apparatus;

Figure 4 is a schematic cross-sectional structural diagram of a loading frame segment provided with a rear servo hydraulic cylinder;

Figure 5 is a schematic structural diagram of a blocking clip;

Figure 6 is a schematic diagram of the structure of the test piece mold;

Fig. 7 is the test method flow chart in embodiment 1;

Fig. 8 is the test method flow chart in embodiment 2;

Fig. 9 is the test method flow chart in embodiment 3;

Figure 10 is a schematic diagram of the structure of the damaged crack specimen with the damage crack perpendicular to the specimen;

Figure 11 is a schematic diagram of the structure of the damaged crack specimen with the damage crack and the specimen obliquely intersecting;

Figure 12 is a schematic diagram of the structure of the damaged crack specimen with a single damage crack and the specimen obliquely intersecting;

Figure 13 is the pull-out force-displacement curve of the bolt end during the test.

In the figure: 1- servo hydraulic cylinder; 11- upper servo hydraulic cylinder; 12- side servo hydraulic cylinder; 13- rear servo hydraulic cylinder 2- connecting frame; 21- displacement protection device; 3- loading frame; 31- loading block plate; 4-ring oil cylinder; 5-anchor rod fixing fixture; 6-blocking clip; 7-base; 8-test anchor rod; 9-damage crack specimen; 91-die plate; 92-nut; 93-insertion hole ; 94 - Anchor hole.

Detailed ways

With reference to FIGS. 1 to 13 , the specific embodiments of the device and method for testing the damage of the anchorage performance of the fracture surrounding rock provided by the present invention are as follows.

In order to simulate the in-situ stress conditions of the anchored surrounding rock and the stress of the bolt along the direction of the bolt, the device can be used to carry out the pull-out test of the fractured surrounding rock under the conditions of different damage forms and different degrees of damage; The pull-out test generally does not consider the surrounding rock damage and in-situ stress conditions. The device loads the damaged fractured surrounding rock specimen through the servo hydraulic cylinder and the loading frame, which provides innovation for the indoor test of the mechanical properties of the bolt and the experimental research on the anchoring performance of the bolt. platform.

Example 1

As shown in Figures 1 to 3, the structure of the fracture surrounding rock anchorage damage test device specifically includes a servo hydraulic cylinder 1, a connecting frame 2, a loading frame 3, an annular oil cylinder 4 and an anchor rod fixing fixture 5. The damaged crack specimen 9 is loaded by the servo hydraulic cylinder 1 and the loading frame 3, thereby simulating the in-situ stress conditions of the anchoring section; the annular oil cylinder 4 is used for loading, so as to simulate the stress on the bolt along the direction of the bolt, and then through the device It can carry out pull-out test of anchoring section under different damage and fissure conditions, common pull-out test of anchor rod, pull-out test of non-damaged anchor section of anchor rod, etc., which provides a foundation for indoor test of anchor rod and research on anchoring performance of anchor rod.

The servo hydraulic cylinder 1 is fixed on the loading frame 3. The servo hydraulic cylinder 1 includes an upper servo hydraulic cylinder 11 and a side servo hydraulic cylinder 12. The upper servo hydraulic cylinder 11 is arranged on the top of the loading frame 3 to load downward, and the side servo hydraulic cylinder 12 corresponds to They are arranged on both sides of the upper servo hydraulic cylinder 11, and the corresponding set of servo hydraulic cylinders have the same loading range. The upper servo hydraulic cylinder 11 is provided with at least two respectively for loading the damaged fracture specimen, and two corresponding side servo hydraulic cylinders 12 are respectively provided on both sides of the loading frame section where the upper servo hydraulic cylinder 11 is located, wherein the length of the loading frame section is according to The anchoring length or length ratio of the bolt is determined, and the loading frame 3 can be divided into one or more than one loading frame segment. A damaged crack specimen 9 or an ordinary anchoring specimen is placed in the loading frame 3, and the servo hydraulic cylinder 1 pressurizes the damaged crack specimen to simulate the in-situ stress of the anchoring section of the bolt. The connecting frame 2 and the loading frame 3 are fixedly connected, the other end of the loading frame 3 is fixed by a baffle plate, and the annular oil cylinder 4 is arranged at the end of the connecting frame 2; Clamp 6 and blocking clamp 6 can better fix the specimen in the loading frame, and can also clamp the anchor rod for ordinary anchor rod pulling test; the connecting frame 2 and the loading frame 3 are set on the fixed base to ensure the stability of the device The connection frame 2 is provided with a displacement protection device 21, and the displacement protection device 21 is non-contact sleeved on the test anchor rod 8, which can measure the displacement of the anchor rod and prevent the damage of the test device due to the excessive tension of the anchor rod. An anchor rod fixing fixture 5 is provided at the end of the annular oil cylinder 4 , one end of the test anchor rod 8 is fixed by the anchor rod fixing fixture 5 , and the other end is set in the damaged crack specimen 9 .

The damaged crack specimen 9 used is provided with one or more drill holes, which are determined according to the range and direction of the cracks. Static crushing agents are provided in the drill holes to generate suitable cracks. The test anchor rod 8 is fixed in the anchor rod hole 94 in the middle of the damaged crack specimen, and is fixed by the anchor rod anchoring agent to better simulate the anchoring force of the anchor rod. The damaged crack test piece 9 is made by using a test piece mold. The test piece mold includes a plurality of mold plates 91. The mold plates 91 are fixed by nuts 92 and insertion holes 93. One of the mold plates 91 is provided with an anchor hole 94, which can be made according to needs. The size of the test piece determines the matching size of the nut and the insertion hole of the mold. In addition, the size of the damaged crack specimen made by the specimen mold is adapted to the size of the loading frame. The damaged crack specimen also includes the damaged crack specimen of the side wall of the drilled hole. After drilling, the drilled specimen is subjected to a servo hydraulic cylinder. After loading, damage cracks are generated on the side wall of the borehole to obtain the specimen with damage cracks on the sidewall of the borehole.

A test method for the damage test of fracture surrounding rock anchorage performance, as shown in Figure 7, utilizes the above-mentioned one kind of fracture surrounding rock anchorage performance damage test device. In this method, the damaged fractures are first made and then the bolts are anchored, and the damage after the damage is studied. When the bolt anchors the surrounding rock, the anchoring performance of the bolt includes:

Step A _1. Make a simulated test piece of similar material or take a field rock to make a simulated test piece. Specifically, according to the actual coal rock or rock formation mechanical parameters of the roadway, similar materials can be configured. The similar materials of the surrounding rock are generally concrete or gypsum, etc., or the on-site rock or similar stone can be directly used to process the similar material or real rock into the test. For the required size, the size of the test piece can be 50cm*50cm*100cm, and small holes can be reserved in advance when using similar materials to simulate the production of the test piece.

Step B _1. Delineate the crack direction and crack range of the simulated specimen, and drill the specimen. Specifically, according to the actual damage and fissure of the surrounding rock of the roadway or according to the test requirements, mark the direction and angle of the fissure with a pen on the processed rock simulation specimen, and determine the hole location and dosage of the filling crushing agent, among which the crushing hole The diameter of the drilled hole is 2cm, the depth of the drilled hole is 30cm, and then a small drilling rig is used to drill the hole.

Step C _1. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the static crushing agent into the drilled hole to make damage cracks.

Step D _1. Observing the position, direction and range of the damage crack, after grinding the surface of the test piece, to obtain the damage crack test piece, drilling the bolt hole on the damage crack test piece, grinding the surface of the test piece flat again, and then testing the test piece. The anchor rod and the anchor rod anchoring agent are put into the anchor rod hole together.

Step E _1. After the bolt anchoring agent is anchored, take out the damaged crack specimen from the specimen mold and put it into the loading frame, the anchor rod fixing fixture is to fix the end of the anchor rod, and the damaged crack specimen is loaded by the servo hydraulic cylinder, The loading force of each servo loading cylinder is determined according to the force of the bolt on site, and different loads can also be applied for multiple tests to compare the anchoring performance under different loads under the test conditions.

Step F1. Pull the bolt through the annular _oil cylinder, record the change of the bolt pulling force during the test, as shown in Figure 13, as well as the damage form, crack width and number of cracks of the damaged crack specimen, and the test can be repeated , under the condition that other conditions remain unchanged, different fracture forms are set to study the influence of different fracture forms on the anchoring section, and then the relationship between the development conditions of the fractures and the anchoring performance of the bolt is found.

In addition, the surface of the damaged fracture specimen can be covered with a rubber film before being placed in the loading frame, and the diameter of the hole into which the static crushing agent is placed should be less than or equal to 20 mm. And as shown in Figure 10 to Figure 12, the damage crack specimen has one or more damage cracks, and the damage crack is perpendicular to the specimen or oblique to the specimen, and the test plan can be changed as needed.

Example 2

As shown in FIGS. 1 to 3 , a fracture surrounding rock anchorage damage testing device, its structure specifically includes a servo hydraulic cylinder 1 , a connecting frame 2 , a loading frame 3 , an annular oil cylinder 4 and an anchor rod fixing fixture 5 . Among them, as shown in FIG. 4 , the servo hydraulic cylinder 1 is fixed on the loading frame 3 , and the servo hydraulic cylinder 1 includes an upper servo hydraulic cylinder 11 , a rear servo hydraulic cylinder 13 and a side servo hydraulic cylinder 12 , and the upper servo hydraulic cylinder 11 is arranged on the The top of the loading frame 3 is loaded downward, the side servo hydraulic cylinders 12 are correspondingly arranged on both sides of the upper servo hydraulic cylinder 11 , and the corresponding set of servo hydraulic cylinders have the same loading range. The rear servo hydraulic cylinder 13 can be loaded along the setting direction of the test bolt 8, so as to simulate the stress of the surrounding rock of the anchoring section in this direction. The blocking clip 6 set at the end of the loading frame 3 can prevent the test displacement of the piece in this direction. The upper servo hydraulic cylinder 11 is provided with one to load the damaged fracture specimen, and two corresponding side servo hydraulic cylinders 12 are respectively provided on both sides of the loading frame section where the upper servo hydraulic cylinder 11 is located, wherein the length of the loading frame section is determined according to the anchor rod. The anchoring length or length ratio is determined, and the loading frame 3 may be divided into only one loading frame segment.

A damaged crack specimen 9 or an ordinary anchoring specimen is placed in the loading frame 3, and the servo hydraulic cylinder 1 pressurizes the damaged crack specimen to simulate the in-situ stress of the anchoring section of the bolt. The connecting frame 2 and the loading frame 3 are fixedly connected, and the annular oil cylinder 4 is arranged at the end of the connecting frame 2; in addition, a blocking clip 6 is provided on the side of the contact end face of the loading frame 3 and the connecting frame 2, and the blocking clip 6 can be better fixed When loading the specimen in the frame, the anchor rod can also be clamped to perform the common anchor rod pull-out test; the connecting frame 2 and the loading frame 3 are set on the fixed base to ensure the stability of the device; the connecting frame 2 is provided with a displacement protection device 21. The displacement protection device 21 is non-contact sleeved on the test anchor rod 8, which can measure the displacement of the anchor rod and prevent the damage of the test device caused by the excessive tension of the anchor rod. An anchor rod fixing fixture 5 is provided at the end of the annular oil cylinder 4 , one end of the test anchor rod 8 is fixed by the anchor rod fixing fixture 5 , and the other end is set in the damaged crack specimen 9 .

The damaged crack specimen 9 used is provided with one or more drill holes, which are determined according to the range and direction of the cracks. Static crushing agents are provided in the drill holes to generate suitable cracks. The test anchor rod 8 is fixed in the anchor rod hole 94 in the middle of the damaged crack specimen, and is fixed by the anchor rod anchoring agent to better simulate the anchoring force of the anchor rod. The damaged crack test piece 9 is made by using a test piece mold. The test piece mold includes a plurality of mold plates 91. The mold plates 91 are fixed by nuts 92 and insertion holes 93. One of the mold plates 91 is provided with an anchor hole 94, which can be made according to needs. The size of the test piece determines the matching size of the nut and the insertion hole of the mold. The test piece mold is to prevent the large volume deformation of the rock test piece and affect the installation of the subsequent test piece on the testing machine. In addition, the size of the damage crack test piece made by the test piece mold is compatible with the size of the loading frame. By making damage crack specimens, the influence of damage cracks in the anchoring section on the anchoring performance during the bolt anchoring process can be simulated and studied. Small drill holes and static breakers can be used to accurately manufacture suitable damage crack specimens. The specimen mold is further developed. It is convenient for the fabrication of damaged crack specimens.

A test method for the damage test of the anchorage performance of the crack surrounding rock, as shown in Figure 8, in this embodiment, the anchor rod is first set in the simulated specimen, and then the damage crack is made, so as to simulate the setting of the anchor rod, when the secondary disturbance Etc. to make the anchoring section produce damage cracks on the anchoring performance of the bolt, using the above-mentioned cracked surrounding rock anchorage performance damage testing device, the steps include:

Step A _2. Make a simulated test piece of similar material or take a field rock to make a simulated test piece. Specifically, according to the actual coal rock or rock stratum mechanical parameters of the site roadway, similar materials are configured. Similar materials are generally concrete or gypsum and other materials, and the size of the simulated specimen is 50cm*50cm*100cm.

Step B ₂ . Drill a bolt hole on the simulated specimen, and put the test bolt together with the bolt anchoring agent into the bolt hole.

Step _C2 . After the bolt anchoring agent is anchored, the crack direction and crack range of the simulated specimen are delineated, and the specimen is drilled.

Step _D2 . Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the static crushing agent into the drilled hole to make damage cracks.

Step E _2. Observing the position, direction and scope of the damage crack, after grinding the surface of the test piece to obtain the damage crack test piece, take out the damage crack test piece from the test piece mold and put it into the loading frame, and fix the anchor rod with the anchor rod fixing fixture The end of the damaged crack is loaded by the servo hydraulic cylinder. The loading force of each servo loading cylinder is determined according to the force of the bolt on site, and different loads can also be applied for multiple tests to compare the anchoring performance under different loads under the test conditions.

Step F ₂ . Pull out the bolt through the annular oil cylinder, as shown in Figure 13, record the change of the pull-out force of the bolt during the test, as well as the damage form, crack width and number of cracks of the damaged crack specimen. The experiment can be repeated, and other conditions remain unchanged, different fracture forms are set to study the influence of different fracture forms on the anchoring section, and then the relationship between different fracture development conditions and the anchorage performance of the bolt can be found.

Among them, the surface of the damaged crack specimen is covered with a rubber film before being placed in the loading frame, which can prevent the specimen from being over-broken and facilitate the statistics of the test results; the diameter of the hole in which the static crushing agent is placed should be less than or equal to 20mm. And as shown in Fig. 10 to Fig. 12, there are one or more damage cracks, and the damage cracks are perpendicular to the specimen or oblique to the specimen.

Example 3

As shown in FIGS. 1 to 3 , a fracture surrounding rock anchorage damage testing device, its structure specifically includes a servo hydraulic cylinder 1 , a connecting frame 2 , a loading frame 3 , an annular oil cylinder 4 and an anchor rod fixing fixture 5 . The servo hydraulic cylinder 1 is fixed on the loading frame 3. The servo hydraulic cylinder 1 includes an upper servo hydraulic cylinder 11 and a side servo hydraulic cylinder 12. The upper servo hydraulic cylinder 11 is arranged on the top of the loading frame 3 to load downward, and the side servo hydraulic cylinder 12 corresponds to They are arranged on both sides of the upper servo hydraulic cylinder 11, and the corresponding set of servo hydraulic cylinders have the same loading range. There are at least two upper servo hydraulic cylinders 11, which independently load the damaged fracture specimen. Two corresponding side servo hydraulic cylinders 12 are respectively provided on both sides of the loading frame section where the upper servo hydraulic cylinder 11 is located.

The length of the loading frame segment is determined according to the anchoring length of the bolt or the length ratio, and the loading frame 3 can be divided into two or more loading frame segments. A damaged crack specimen 9 or an ordinary anchoring specimen is placed in the loading frame 3, and the servo hydraulic cylinder 1 pressurizes the damaged crack specimen to simulate the in-situ stress of the anchoring section of the bolt. The connection frame 2 and the loading frame 3 are fixedly connected, and the other end of the loading frame 3 is open, so the fabrication of control damage cracks can be observed in real time during the test. The annular oil cylinder 4 is arranged at the end of the connecting frame 2; in addition, a blocking clip 6 is arranged on the contact end face side of the loading frame 3 and the connecting frame 2. The blocking clip 6 can better fix the specimen in the loading frame, and can also clamp Tighten the anchor rod for ordinary anchor rod pulling test; the connecting frame 2 and the loading frame 3 are set on the fixed base to ensure the stability of the device; the connecting frame 2 is provided with a displacement protection device 21, and the non-contact sleeve of the displacement protection device 21 Set on the test bolt 8, it can measure the displacement of the bolt and prevent the damage of the test device caused by the excessive tension of the bolt. An anchor rod fixing fixture 5 is provided at the end of the annular oil cylinder 4 , one end of the test anchor rod 8 is fixed by the anchor rod fixing fixture 5 , and the other end is set in the damaged crack specimen 9 . Among them, the setting of the blocking clip 6 can effectively fix the test piece, and can also fix one end of the anchor rod in the common anchor rod pulling test; the displacement protection device 21 can prevent the anchor rod from excessively stretching, record the displacement, and protect the test. device.

The damaged crack specimen 9 is provided with one or more drill holes, which are determined according to the range and direction of the cracks, and a time-delayed static crushing agent is arranged in the drill holes to generate suitable cracks. The test anchor rod 8 is fixed in the anchor rod hole in the middle of the damaged crack specimen, and is fixed by the anchor rod anchoring agent to better simulate the anchoring force of the anchor rod. In addition, the size of the damage crack specimen made by the specimen mold is adapted to the size of the inside of the loading frame.

A test method for damage testing of fracture surrounding rock anchorage performance, as shown in Figure 9, in this embodiment, the damage cracks of the specimen are made during the bolt pulling test process, so that the development process of the damage cracks can be simulated. The influence of the rod anchorage performance, using the above-mentioned one kind of fracture surrounding rock anchorage performance damage testing device, the steps include:

Step A _3. Make a simulated test piece of similar material or take a field rock to make a simulated test piece. Specifically, according to the actual coal rock or rock stratum mechanical parameters of the site roadway, similar materials are configured. Similar materials are generally concrete or gypsum and other materials, and the size of the simulated specimen is 50cm*50cm*100cm.

Step B ₃ . Drill a hole for the bolt on the simulated specimen, and put the test bolt together with the bolt anchoring agent into the hole for the bolt.

Step C3. After the bolt anchoring agent is anchored, the crack direction and crack range _of the simulated specimen are delineated, and the specimen is drilled.

Step _D3 . Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the delayed static crushing agent into the drilled hole, wherein the delayed static crushing agent can delay the crushing test. Parts, you can also use a water-expandable static crushing agent to start cracking after water injection.

Step E _3. Take out the test piece from the test piece mold, after grinding the surface of the test piece, put the simulated test piece into the loading frame, fix the end of the bolt with the anchor rod fixing fixture, and use the servo hydraulic cylinder to damage the crack test piece. to load. The loading force of each servo loading cylinder is determined according to the force of the bolt on site, and different loads can also be applied for multiple tests to compare the anchoring performance under different loads under the test conditions.

Step F3. Pull the anchor rod through the annular oil cylinder, as shown in Figure ₁₃ , delay the action of the static crushing agent during the pulling process, and simulate the crack expansion of the specimen within the delimited range to obtain the damaged crack specimen; record the test process. The bolt pull-out force changes, as well as the damage form, crack width and number of cracks of the damaged crack specimen. The experiment can be repeated, and other conditions remain unchanged, different fracture forms are set to study the influence of different fracture forms on the anchoring section, and then the relationship between different fracture development conditions and the anchorage performance of the bolt can be found.

Among them, the damaged crack specimen is only covered with rubber film on the side surface before being placed in the loading frame; the diameter of the hole in which the static crushing agent is placed is less than or equal to 20 mm. And as shown in Fig. 10 to Fig. 12, there are one or more damage cracks, and the damage cracks are perpendicular to the specimen or oblique to the specimen.

Example 4

The test is carried out by using a fracture surrounding rock anchoring performance damage testing device in Example 3, and the method for performing the bolt pull-out test on the device is further described in this example.

Step A _4. Fix the end of the test anchor rod through the anchor rod fixing fixture, and fix the other side of the test anchor rod through the blocking clip structure.

Step B4 _. Pulling the anchor rod through the annular oil cylinder, the change of the pull-out force is shown in Figure 13, in this embodiment, the pull-out force of the anchor rod is specifically the pull-out force of the non-damaged anchor rod, and the anchor rod during the test is recorded. Rod pullout force changes.

Through this test, the bolt can be pulled out, and the ordinary bolt pull test can be used to compare and analyze the impact of the surrounding rock crack damage on the bolt anchorage.

The test methods in the above-mentioned Embodiments 1 to 4 include the pull-out test of the anchor rod after making the damaged crack specimen. On the basis of making full use of the structure of the device, the anchor can be adjusted to simulate different ground stress conditions by adjusting the loading of the servo hydraulic cylinder. The influence of the anchorage performance of the anchorage section of the rod is studied by setting different damage cracks to conduct the anchorage performance test to study the influence of the damage cracks on the anchorage force of the anchorage section, and the influence of the development process of the cracks on the anchorage performance of the anchor rod is studied by the time-delayed static breaker. The anchoring performance of the anchoring section before and after the simulated crack is compared to study the anchoring performance of the bolt. This method also has the advantages of flexible operation and good test repeatability.

Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the essential scope of the present invention should also belong to the present invention. the scope of protection of the invention.

Claims (6)

1. A test method for the damage test of the anchorage performance of the surrounding rock of the crack, using a device for testing the damage of the anchorage performance of the surrounding rock of the crack, including a servo hydraulic cylinder, a connecting frame, a loading frame, an annular oil cylinder and a bolt fixing fixture, the servo hydraulic The cylinder is fixed on the loading frame, and the servo hydraulic cylinder includes an upper servo hydraulic cylinder and a side servo hydraulic cylinder; the damaged crack specimen is placed in the loading frame, and the servo hydraulic cylinder pressurizes the damaged crack specimen; the connecting frame and the loading frame Fixed connection, the annular oil cylinder is arranged at the end of the connection frame; the end of the annular oil cylinder is provided with an anchor rod fixing fixture; one end of the test anchor rod is fixed by the anchor rod fixing fixture, and the other side is set in the damaged crack specimen; The damaged crack specimen is provided with one or more drill holes, and a time-delayed static crushing agent is arranged in the drill hole; the test bolt is fixed in the middle of the damaged crack specimen; A blocking clip is arranged on one side of the contact end face, and the connection frame and the loading frame are arranged on the fixed base; a displacement protection device is arranged on the connection frame, and the displacement protection device is sleeved on the anchor rod in a non-contact manner; it is characterized in that the steps include: : Step A _2. Make a simulated test piece of similar material or take a field rock to make a simulated test piece; Step B _2. Drilling a bolt hole on the simulated specimen, and putting the test bolt and the bolt anchoring agent into the bolt hole together; Step _C2 . After the bolt anchoring agent is anchored, the crack direction and crack range of the simulated test piece are delineated, and the test piece is drilled; Step D _2. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the time-delayed static crushing agent into the drilled hole to make damage cracks; Step E _2. Observing the position, direction and scope of the damage crack, after grinding the surface of the test piece to obtain the damage crack test piece, take out the damage crack test piece from the test piece mold and put it into the loading frame, and fix the anchor rod with the anchor rod fixing fixture The end of the damaged crack is loaded by the servo hydraulic cylinder; Step F ₂ . Pulling the bolt through the annular oil cylinder, recording the change of the pulling force of the bolt during the test, as well as the damage form, crack width and number of cracks of the damaged crack specimen. 2. A test method for damage testing of fracture surrounding rock anchorage performance, using a device for testing fracture surrounding rock anchorage performance damage, comprising a servo hydraulic cylinder, a connecting frame, a loading frame, an annular oil cylinder and an anchor rod fixing fixture, the servo hydraulic The cylinder is fixed on the loading frame, and the servo hydraulic cylinder includes an upper servo hydraulic cylinder and a side servo hydraulic cylinder; the damaged crack specimen is placed in the loading frame, and the servo hydraulic cylinder pressurizes the damaged crack specimen; the connecting frame and the loading frame Fixed connection, the annular oil cylinder is arranged at the end of the connection frame; the end of the annular oil cylinder is provided with an anchor rod fixing fixture; one end of the test anchor rod is fixed by the anchor rod fixing fixture, and the other side is set in the damaged crack specimen; The damaged crack specimen is provided with one or more drill holes, and a time-delayed static crushing agent is arranged in the drill hole; the test bolt is fixed in the middle of the damaged crack specimen; A blocking clip is arranged on one side of the contact end face, and the connection frame and the loading frame are arranged on the fixed base; a displacement protection device is arranged on the connection frame, and the displacement protection device is sleeved on the anchor rod in a non-contact manner; it is characterized in that the steps include: : Step A3. _Make a simulated test piece of similar material or take a field rock to make a simulated test piece; Step B _3. Drilling a bolt hole on the simulated specimen, and putting the test bolt and the bolt anchoring agent into the bolt hole together; Step C3. After the bolt anchoring agent is anchored, the crack direction and crack range _of the simulated specimen are delineated, and the specimen is drilled; Step D _3. Put the drilled simulated test piece into the test piece mold, fasten the test piece mold with nuts, and put the time-delayed static crushing agent into the drilled hole; Step E _3. Take out from the test piece mold, after grinding the surface of the test piece, put the simulated test piece into the loading frame, fix the end of the anchor rod with the anchor rod fixing fixture, and load the damaged crack test piece through the servo hydraulic cylinder ; Step F ₃ . Pulling the bolt through the annular oil cylinder, delaying the action of the static crushing agent during the pulling process, simulating the crack expansion of the specimen within the delimited range to obtain a damaged crack specimen; recording the bolt pulling force during the test process Variations, as well as the damage pattern, crack width, and number of cracks in the damage-cracked specimen. 3. the test method of a kind of crack surrounding rock anchorage damage test according to any one of claims 1-2, it is characterized in that, described damage crack test piece is made by test piece mold, and test piece mold comprises a plurality of molds The plate and the die plate are fixed by nuts and insertion holes; the size of the damaged crack test piece made by the test piece mold is adapted to the size of the inside of the loading frame. 4. The test method for the damage test of the anchorage performance of a crack surrounding rock according to any one of claims 1-2, wherein the upper servo hydraulic cylinder is provided with at least 2 to load the damaged crack specimen respectively, Two corresponding side servo hydraulic cylinders are respectively provided on both sides of the loading frame section where the upper servo hydraulic cylinder is located. 5. The test method for the damage test of the anchorage performance of a crack surrounding rock according to claim 2, wherein the damaged crack specimen is coated with a rubber film on the surface before being put into the loading frame; the time-delay static The diameter of the hole into which the crushing agent is placed is less than or equal to 20mm; the damaged crack specimen also includes the side wall of the drilled hole. Cracks were obtained from the borehole wall damage crack specimens. 6. the test method of a kind of crack surrounding rock anchorage damage test according to claim 5, is characterized in that, described damage crack test piece is made from similar material, and similar material is concrete or gypsum, described damage crack One or more damage cracks are perpendicular to the specimen or oblique to the specimen.

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