Expansion hole test device and expansion hole test method

Abstract

The present invention discloses a hole expansion test device, which includes a steel base, an expander, and a water injection pump. A fixed groove is provided in the middle of the steel base, and a first water injection channel is provided at the bottom of the fixed groove. A sample is provided on the outer periphery of the expander, and the expander is located in the middle of the fixed groove. One end of the expander is detachably connected to the bottom of the fixed groove. The water outlet end of the water injection pump is connected to one end of the first water injection channel via a water injection pipe. The sample is cylindrical in structure, one end of the sample is located on the steel base, and a water injection port is provided at one end of the expander. The water injection port is detachably connected to the other end of the first water injection channel. The present invention also discloses a hole expansion test method. Compared with the prior art, the hole expansion test device of the present invention has a simple structure, is easy to operate, and has a low preparation cost. It can reflect the mechanical response law and deformation and failure characteristics of the sample under the action of hole expansion stress.

Description

Technical Field

[0001] The present invention relates to the field of geotechnical engineering, and in particular to an expansion hole test device and an expansion hole test method. Background Art

[0002] In the field of traditional geotechnical engineering, the deformation and strength characteristics of rock and soil are usually characterized by test parameters obtained from tests such as Brazilian splitting, uniaxial compression, triaxial compression, and direct shear. However, with the development of geotechnical engineering towards deep engineering and the application of technologies such as static blasting and hydraulic fracturing, the failure mechanism, mechanical response, and deformation and failure characteristics of rock and soil under radial stress have received more and more attention from scholars.

[0003] At present, radial expansion hole test instruments are often replaced by grouting plugs, hole sealers, etc. The test instruments are difficult to operate in the laboratory, the test process is not systematic, and the test measurement accuracy is low.

[0004] Therefore, how to provide a hole expansion test device that can achieve the technical effect of testing the mechanical response and deformation and failure characteristics of various rocks, mortars and other materials under radial stress is a technical problem that technical personnel in this field urgently need to solve. Summary of the Invention

[0005] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a hole expansion test device, which can achieve the technical effect of testing the mechanical response and deformation and failure characteristics of various rocks, mortars and other materials under radial stress.

[0006] To achieve the above-mentioned objectives, the present invention provides an expansion hole test device, which includes: a steel base, a fixed groove is provided in the middle of the steel base, the inner side wall of the fixed groove is a cylindrical structure, and a first water injection channel is provided at the bottom of the fixed groove; an expander, the outer side wall of the expander is a cylindrical structure, a sample is provided on the outer periphery of the expander, the expander is located in the middle of the fixed groove, and one end of the expander is detachably connected to the bottom of the fixed groove; a water injection pump, the water outlet end of the water injection pump is connected to one end of the first water injection channel through a water injection pipe, and the water inlet end of the water injection pump is connected to the water tank through a water supply pipe; wherein, the sample is a cylindrical structure, one end of the sample is located on the steel base, and a water injection port is provided at one end of the expander, and the water injection port is detachably connected to the other end of the first water injection channel.

[0007] In the first aspect, the expansion hole test device further includes a control system connected to the water injection pump.

[0008] In the first aspect, the expander includes: an expansion hole seat, which is located in the middle of the fixed groove, and one end of the expansion hole seat is detachably connected to the bottom of the fixed groove; a sliding rod, which is located in the center of the expansion hole seat, and one end of the sliding rod is fixedly connected to the other end of the expansion hole seat; an inner steel wire rubber lining, which is a cylindrical structure, and the inner steel wire rubber lining is sleeved on the outer periphery of the sliding rod, and one end of the inner steel wire rubber lining is sealed and detachably connected to the other end of the expansion hole seat; a moving piston, which is a cylindrical structure, and the moving piston is sleeved on the outer periphery of the sliding rod, and the moving piston is sealingly and movably connected to the sliding rod, and one end of the moving piston is sealed and detachably connected to the other end of the inner steel wire rubber lining; wherein, the water injection port is opened on the expansion hole seat; and the sample is sleeved on the outer periphery of the inner steel wire rubber lining.

[0009] In the first aspect, the expansion hole test device also includes a steel ring, which is arranged on the periphery of the steel wire lined rubber, the steel ring is located above the sample, and one end of the steel ring is in contact with and connected to the sample; the stiffness of the steel ring is the same as the stiffness of the sample; the maximum radial expansion hole pressure of the steel wire lined rubber is 20MPa.

[0010] In the first aspect, the inner diameter of the sample is not larger than the inner diameter of the fixing groove, and the inner diameter of the sample is larger than the outer diameter of the expansion hole seat; the outer diameter of the movable piston is the same as the outer diameter of the expansion hole seat; the inner diameter of the steel ring is the same as the inner diameter of the sample.

[0011] In the first aspect, the expansion hole test device also includes: a plurality of displacement sensors, which are evenly distributed on the outer wall of the sample; a plurality of acoustic emission probes, which are evenly distributed on the outer wall of the sample; a high-speed camera, which is located on the outside of the steel base, and the camera end of the high-speed camera is arranged opposite to the sample; an acoustic emission detector, which is connected to the plurality of acoustic emission probes; wherein, the plurality of displacement sensors, the high-speed cameras and the acoustic emission detectors are all connected to the control system.

[0012] In the first aspect, the expansion hole test device further includes a pressure gauge, which is disposed at one end of the water injection pipe close to the first water injection channel, and is connected to the control system.

[0013] The present invention also provides a hole expansion test method, which is used for the hole expansion test of the above-mentioned hole expansion test device, and the hole expansion test method includes: preparing a sample; sleeve the prepared sample on the periphery of the steel wire lined rubber, and then sleeve a steel ring on the top of the sample; arranging a displacement sensor on the outer wall of the sample, arranging an acoustic emission probe on the outer wall of the sample, and aiming the camera end of a high-speed camera at the sample; turning on the displacement sensor, the acoustic emission probe and the high-speed camera, and controlling a water injection pump through a control system to inject water into the steel wire lined rubber to perform a hole expansion test; recording the hole expansion pressure applied to the sample during the water injection process, the radial displacement of the outer wall of the sample, the acoustic emission data, and the rupture of the sample along the axial direction of the hole, obtaining the compressive strength of the sample under the action of the hole expansion, and obtaining the tensile strength of the sample through the compressive strength; analyzing the circumferential and radial rupture characteristics of the sample, the relationship between the compressive strength and the deformation state of the sample, understanding the cracking evolution process of the sample, and quantitatively analyzing the radial stiffness evolution law of the sample after rupture.

[0014] In the second aspect, the sample preparation specifically includes: drilling a cylindrical rock sample, polishing the inner and outer surfaces of the cylindrical rock sample, and then sleeve and fix the steel sleeve tightly against the outer wall of the cylindrical rock sample to obtain the sample, and the stiffness of the sample is the same as the environmental stiffness; or, using mortar casting to obtain a cylindrical mortar sample, polishing the inner and outer surfaces of the cylindrical mortar sample, and then sleeve and fix the steel sleeve tightly against the outer wall of the cylindrical mortar sample to obtain the sample, and the stiffness of the sample is the same as the environmental stiffness.

[0015] In the second aspect, the steel sleeve is a cylindrical structure, and the steel sleeve includes two semi-cylinders, and the two semi-cylinders are detachably connected by a plurality of bolts.

[0016] Beneficial effects:

[0017] An expansion hole test device of the present invention includes a steel base, an expander, a water injection pump, a control system, a displacement sensor, an acoustic emission probe, a high-speed camera, an acoustic emission detector, and a steel ring. The steel base is used to provide a fixed position for the expander. A fixing groove with a cylindrical structure of an inner wall layer is opened at the center position of the steel base. One end of the expander is located at the center position of the fixing groove, and one end of the expander is detachably connected to the steel base, so that the expander can be cleaned and replaced; the expander includes an expansion hole seat, a sliding rod, an inner steel wire rubber lining and a movable piston. The sliding rod is fixed at the center position of the expansion hole seat. The movable piston mounted on the sliding rod can slide up and down on the sliding rod. The two ends of the inner steel wire rubber lining are respectively and detachably connected to the expansion hole seat and the movable piston. The expansion hole seat, the lining steel wire rubber and the movable piston are formed in the periphery of the sliding rod. At the same time, the lining steel wire rubber is easy to disassemble so as to replace the lining steel wire rubber. The sample is sleeved on the periphery of the lining steel wire rubber. When water is flushed into the closed space, as the amount of water increases, the lining steel wire rubber expands outwards due to the water pressure, thereby squeezing the inner wall of the sample, so that the sample is subjected to the expansion hole pressure from the radial direction outward. The expansion hole pressure is obtained by monitoring the pressure of the water injection pump through the control system. At the moment the sample ruptures, the expansion hole pressure on the sample reaches the maximum value, and then the expansion hole pressure value decreases. After the expansion hole test is completed, the water injection pump is controlled by the control system to reversely absorb water to discharge the water inside the lining steel wire rubber. The maximum expansion hole pressure The force is the compressive strength of the sample, and the tensile strength of the sample can also be calculated through the compressive strength; at the same time, a pressure gauge is set on the water injection pipe. By comparing the monitoring value of the pressure gauge and the pressure monitoring value of the water injection pump by the control system, it can be judged whether there is water leakage inside the lining steel wire rubber; a number of displacement sensors are arranged on the outer wall of the sample. The displacement sensor can be any one of a probe-type displacement sensor and a chain-type displacement sensor. If the displacement sensor is a probe-type displacement sensor, the displacement probes of several probe-type displacement sensors are evenly arranged on the outer wall of the sample to monitor the radial displacement of the outer wall of the sample after the expansion hole test is carried out on the sample. If the displacement sensor is a chain-type displacement sensor, several chain displacement sensors are wound around the test The outer wall of the sample is set up around the periphery to test the circumferential displacement of the sample; the acoustic emission probe is used to measure the acoustic emission data of the sample in the expansion hole test to obtain the internal rupture of the sample; the high-speed camera is used to monitor the external rupture of the sample along the axial direction of the hole in the expansion hole test; by monitoring the changes in the expansion hole pressure, acoustic emission data, and the radial and circumferential deformation of the sample in the expansion hole test, the circumferential and radial rupture characteristics of the sample can be analyzed, the relationship between the compressive strength and the deformation state can be analyzed, the evolution process of the sample cracking can be understood, and the evolution law of the radial stiffness of the sample after rupture can be quantitatively analyzed; the steel ring is used to limit the position of the inner lining steel wire rubber in the expansion hole test to prevent the inner lining steel wire rubber from bulging at the top due to pressure after water injection;In addition, the expansion hole test device of the present invention has a simple structure, is easy to operate, and has a low production cost. It can reasonably, objectively, and accurately reflect the mechanical response law and deformation and failure characteristics of the sample under the action of expansion hole stress. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 The present invention is a schematic structural diagram of a hole expansion test device when a sample is not set and sensors are not arranged.

[0020] Figure 2 The present invention is a schematic structural diagram of a hole expansion test device used for a sample hole expansion test.

[0021] Reference numerals:

[0022] 1. Steel base;

[0023] 2. Expander; 21. Expansion hole seat; 22. Sliding rod; 23. Steel wire rubber lining; 24. Moving piston;

[0024] 3. Sample;

[0025] 4. Steel ring;

[0026] 5. Acoustic emission probe;

[0027] 6. Pressure gauge;

[0028] 7. Probe type displacement sensor; 71. Displacement probe; 72. Magnetic table base;

[0029] 101. Fixing groove; 102. First water injection channel; 103. Water injection pipe; 104. Water injection port. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the embodiments described are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this invention.

[0031] Example 1

[0032] like Figures 1-2As shown, this embodiment 1 provides an expansion hole test device, which includes: a steel base 1, a fixed groove 101 is provided in the middle of the steel base 1, the inner side wall of the fixed groove 101 is a cylindrical structure, and a first water injection channel 102 is provided at the bottom of the fixed groove 101; an expander 2, the outer side wall of the expander 2 is a cylindrical structure, and a sample 3 is provided on the outer periphery of the expander 2, the expander 2 is located in the middle of the fixed groove 101, and one end of the expander 2 is detachably connected to the bottom of the fixed groove 101; a water injection pump, the water outlet end of the water injection pump is connected to one end of the first water injection channel 102 through a water injection pipe 103, and the water inlet end of the water injection pump is connected to the water tank through a water supply pipe; wherein, the sample 3 is a cylindrical structure, one end of the sample 3 is located on the steel base 1, and a water injection port 104 is provided at one end of the expander 2, and the water injection port 104 is detachably connected to the other end of the first water injection channel 102.

[0033] An expansion hole test device of the present invention includes a steel base 1, an expander 2, a water injection pump, a control system, a displacement sensor, an acoustic emission probe, a high-speed camera, an acoustic emission detector, and a steel ring 4. The steel base 1 is used to provide a fixed position for the expander. A fixing groove 101 with a cylindrical structure of an inner wall layer is opened at the center position of the steel base 1. One end of the expander 2 is located at the center position of the fixing groove 101, and one end of the expander 2 is detachably connected to the steel base 1, so that the expander 2 can be cleaned and replaced; the expander 2 includes an expansion hole seat 21, a sliding rod 22, a steel wire rubber lining 23 and a movable piston 24. The sliding rod 22 is fixed at the center position of the expansion hole seat 21. The movable piston 24 sleeved on the sliding rod 22 can slide up and down on the sliding rod 22. The steel wire rubber lining The two ends of the wire rubber 23 are respectively connected to the expansion hole seat 21 and the movable piston 24 in a sealed and detachable manner, and a closed space consisting of the expansion hole seat 21, the lined wire rubber 23 and the movable piston 24 is formed on the periphery of the sliding rod 22. At the same time, it is convenient to disassemble the lined wire rubber 23, so as to replace the lined wire rubber 23; the sample 3 is sleeved on the periphery of the lined wire rubber 23. When water is flushed into the closed space, as the amount of water increases, the lined wire rubber 23 expands outward under the water pressure, thereby squeezing the inner side wall of the sample 3, so that the sample 3 is subjected to an expansion hole pressure from the radial direction outward. The expansion hole pressure is obtained by monitoring the pressure of the water injection pump through the control system. At the moment the sample 3 ruptures, the expansion hole pressure on the sample 3 reaches a maximum value, and then the expansion hole pressure value decreases, and the expansion hole test After the test is completed, the control system controls the water injection pump to reversely absorb water so that the water inside the lined steel wire rubber 23 is discharged; the maximum expansion hole pressure is the compressive strength of the sample 3, and the tensile strength of the sample 3 can also be calculated through the compressive strength; at the same time, a pressure gauge 6 is set on the water injection pipe 103, and by comparing the monitoring value of the pressure gauge 6 and the pressure monitoring value of the water injection pump of the control system, it can be judged whether there is water leakage inside the lined steel wire rubber 23; a number of displacement sensors are arranged on the outer wall of the sample 3, and the displacement sensor can be any one of a probe-type displacement sensor 7 and a chain-type displacement sensor. If the displacement sensor is a probe-type displacement sensor 7, the displacement probes 71 of the several probe-type displacement sensors 7 are evenly arranged on the outer wall of the sample 3 to monitor the sample 3. The radial displacement of the outer wall of the sample 3 after the hole expansion test. If the displacement sensor is a chain displacement sensor, several chain displacement sensors are arranged around the outer wall of the sample 3 to measure the circumferential displacement of the sample 3. The acoustic emission probe 5 is used to measure the acoustic emission data of the sample 3 during the hole expansion test to obtain the internal rupture of the sample 3. The high-speed camera is used to monitor the external rupture of the sample 3 along the axial direction of the hole during the hole expansion test. By monitoring the changes in the hole expansion pressure, the acoustic emission data, and the radial and circumferential deformation of the sample during the hole expansion test, the circumferential and radial rupture characteristics of the sample can be analyzed, the relationship between the compressive strength and the deformation state can be analyzed, the evolution process of the sample cracking can be understood, and the evolution law of the radial stiffness of the sample after rupture can be quantitatively analyzed.The steel ring 4 is used to limit the position of the inner steel wire rubber liner 23 during the expansion test, preventing it from protruding from the top due to pressure after water injection. Furthermore, the expansion test device of the present invention has a simple structure, is easy to operate, and has low production costs. It can reasonably, objectively, and accurately reflect the mechanical response and deformation and failure characteristics of the specimen 3 under the action of expansion stress.

[0034] In some possible implementations, the expansion hole testing device further includes a control system, and the control system is connected to the water injection pump.

[0035] Specifically, the control system is used to control the water injection pump to inject water into the inner steel wire rubber 23, or to control the water injection pump to reversely extract water from the inner steel wire rubber 23. In addition, the control system is also used to monitor the expansion hole pressure in the inner steel wire rubber 23 reflected by the water injection pump.

[0036] In some possible implementations, the expander 2 includes: an expansion hole seat 21, which is located in the middle of the fixed groove 101, and one end of the expansion hole seat 21 is detachably connected to the bottom of the fixed groove 101; a sliding rod 22, which is located in the center of the expansion hole seat 21, and one end of the sliding rod 22 is fixedly connected to the other end of the expansion hole seat 21; an inner lining steel wire rubber 23, which is a cylindrical structure, and the inner lining steel wire rubber 23 is sleeved on the outer periphery of the sliding rod 22, and one end of the inner lining steel wire rubber 23 is sealed and detachably connected to the other end of the expansion hole seat 21; a moving piston 24, which is a cylindrical structure, and the moving piston 24 is sleeved on the outer periphery of the sliding rod 22, and the moving piston 24 is sealed and movably connected to the sliding rod 22, and the moving piston One end of the plug 24 is sealed and detachably connected to the other end of the lined steel wire rubber 23; wherein, the water injection port 104 is opened on the expansion hole seat 21; the sample 3 is sleeved on the periphery of the lined steel wire rubber 23; the expansion hole test device also includes a steel ring 4, which is sleeved on the periphery of the lined steel wire rubber 23, the steel ring 4 is located above the sample 3, and one end of the steel ring 4 is in contact with the sample 3; the stiffness of the steel ring 4 is the same as that of the sample 3; the maximum radial expansion hole pressure of the lined steel wire rubber 23 is 20MPa; the inner diameter of the sample 3 is not greater than the inner diameter of the fixing groove 101, and the inner diameter of the sample 3 is greater than the outer diameter of the expansion hole seat 21; the outer diameter of the movable piston 24 is the same as the outer diameter of the expansion hole seat 21; the inner diameter of the steel ring 4 is the same as the inner diameter of the sample 3.

[0037] Specifically, the expansion hole seat 21 is detachably connected to the bottom of the fixed groove 101, so that the expander 2 can be removed and the lining steel wire rubber 23 can be replaced; the sliding rod 22 is located at the central axis of the lining steel wire rubber 23, so that the lining steel wire rubber 23 is stable in the center position; the movable piston 24 can move up and down on the sliding rod 22. When water is filled into the lining steel wire rubber 23, the movable piston 24 slides down, so that the lining steel wire rubber 23 is fixed in the space enclosed by the movable piston 24, the steel ring 4, the sample 3, and the fixed groove 101, so that the inner wall of the sample 3 is subjected to uniform radial expansion hole pressure; the steel ring 4 is used to limit the position of the lining steel wire rubber 23 during the expansion hole test to avoid the lining steel wire rubber 23 bulging at the top due to pressure after water injection, thereby affecting the force on the sample 3.

[0038] In some possible implementations, the expansion hole test device also includes: a number of displacement sensors, which are evenly distributed on the outer wall of the sample 3; a number of acoustic emission probes 5, which are evenly distributed on the outer wall of the sample 3; a high-speed camera, which is located on the outside of the steel base 1, and the camera end of the high-speed camera is arranged opposite to the sample 3; an acoustic emission detector, which is connected to the number of acoustic emission probes 5; wherein, the number of displacement sensors, the high-speed camera 6 and the acoustic emission detector are all connected to the control system.

[0039] Specifically, the displacement sensor can be any one of a probe-type displacement sensor 7 and a chain-type displacement sensor. If the displacement sensor is a probe-type displacement sensor 7, the displacement probes 71 of several probe-type displacement sensors 7 are evenly arranged on the outer wall of the sample 3 to monitor the radial displacement of the outer wall of the sample 3 after the expansion hole test. The displacement probes 71 are fixed to the steel base through a magnetic table base 72, so that the monitoring position of the probe-type displacement sensor 7 can be moved; if the displacement sensor is a chain-type displacement sensor, several chain-type displacement sensors are all arranged around the outer wall of the sample 3 for a week. The apparatus is configured to test the circumferential displacement of the sample 3; the acoustic emission probe 5 is used to measure the acoustic emission data of the sample 3 in the hole expansion test, so as to obtain the internal rupture condition of the sample 3; the high-speed camera is used to monitor the external rupture condition of the sample 3 along the axial direction of the hole in the hole expansion test; by monitoring the changes in the hole expansion pressure, the acoustic emission data, and the radial and circumferential deformation of the sample in the hole expansion test, the circumferential and radial rupture characteristics of the sample can be analyzed, the relationship between the compressive strength and the deformation state can be analyzed, the cracking evolution process of the sample can be understood, and the radial stiffness evolution law of the sample after rupture can be quantitatively analyzed.

[0040] In some possible implementations, the expansion hole test device further includes a pressure gauge 6 , which is disposed at one end of the water injection pipe 103 close to the first water injection channel 102 , and is connected to the control system.

[0041] Specifically, the pressure gauge 6 is used to monitor the expansion hole pressure inside the lined steel wire rubber 23. By comparing the monitoring value of the pressure gauge 6 with the pressure monitoring value of the water injection pump by the control system, it can be determined whether there is water leakage inside the lined steel wire rubber 23.

[0042] Example 2

[0043] like Figures 1-2 As shown, embodiment 2 of the present invention provides an expansion hole test method, which is used for an expansion hole test of an expansion hole test device of embodiment 1 above, and the expansion hole test method includes: preparing a sample; sleeve the prepared sample on the periphery of the lined steel wire rubber, and then sleeve a steel ring on the top of the sample; arrange a displacement sensor on the outer wall of the sample, arrange an acoustic emission probe on the outer wall of the sample, and aim the camera end of a high-speed camera at the sample; start the operation of the displacement sensor, the acoustic emission probe and the high-speed camera, and control the water injection pump to inject water into the lined steel wire rubber through a control system to perform an expansion hole test; record the expansion hole pressure on the sample during the water injection process, the radial displacement of the outer wall of the sample, the acoustic emission data, and the rupture of the sample along the axial direction of the hole, and obtain the compressive strength of the sample under the action of the expansion hole, and obtain the compressive strength through the compressive strength The tensile strength of the sample is obtained; the circumferential and radial fracture characteristics of the sample, the relationship between the compressive strength and the deformation state of the sample are analyzed, the cracking evolution process of the sample is understood, and the radial stiffness evolution law of the sample after fracture is quantitatively analyzed; the sample preparation specifically includes: drilling a cylindrical rock sample, polishing the inner and outer surfaces of the cylindrical rock sample, and then sleeved and fixed a steel sleeve on the outer wall of the cylindrical rock sample to obtain the sample, and the stiffness of the sample is the same as the environmental stiffness; or, using mortar casting to obtain a cylindrical mortar sample, polishing the inner and outer surfaces of the cylindrical mortar sample, and then sleeved and fixed a steel sleeve on the outer wall of the cylindrical mortar sample to obtain the sample, and the stiffness of the sample is the same as the environmental stiffness; the steel sleeve is a cylindrical structure, and the steel sleeve includes two semi-cylinders, and the two semi-cylinders are detachably connected by a plurality of bolts.

[0044] Specifically, the present invention provides a hole expansion test method, which places a sample in a hole expansion test device for a hole expansion test, monitors the hole expansion pressure on the sample, the radial displacement of the outer wall of the sample, the acoustic emission data, and the rupture of the sample along the axial direction of the hole, obtains the compressive strength of the sample under the action of the hole expansion, obtains the tensile strength of the sample through the compressive strength, analyzes the circumferential and radial rupture characteristics of the sample, and the relationship between the compressive strength and the deformation state of the sample, recognizes the cracking evolution process of the sample, and quantitatively analyzes the radial stiffness evolution law of the sample after rupture, so as to provide a basis for in-depth understanding of the failure mechanism, mechanical response and deformation failure characteristics of materials such as rock and soil, mortar mixtures under radial hole expansion stress. It is of great significance for research and application in the fields of energy extraction, transportation tunnels, slope protection, underground engineering, mining engineering, foundation anti-tilting, anti-floating and other engineering. In addition, the environmental stiffness is calculated by the elastic modulus and Poisson's ratio of the actual environmental rock, and then the environmental stiffness is simulated by setting a steel sleeve on the outer wall of the rock sample or mortar sample. The stiffness conditions of the rock sample-steel sleeve assembly and the mortar sample-steel sleeve assembly formed by putting the steel sleeve on the outer wall of the rock sample or mortar sample are equal to those of semi-infinite rock, which is used to analyze the mechanical response and failure characteristics of the sample under the action of radial expansion stress under environmental stiffness.

[0045] It should be noted that the expansion hole test method in the second embodiment is used for the expansion hole test of an expansion hole test device in the first embodiment above, so the performance principle of the expansion hole test device will not be described here in detail, and the part not described in detail can be referred to the first embodiment.

[0046] The above describes in detail the preferred embodiments of the present invention. It should be understood that those skilled in the art can make numerous modifications and variations based on the concepts of the present invention without inventive effort. Therefore, any technical solutions that can be derived by those skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A hole expansion test device, characterized in that: The expansion hole test device comprises: A steel base (1), wherein a fixing groove (101) is provided in the middle of the steel base (1), the inner side wall of the fixing groove (101) is cylindrical, and a first water injection channel (102) is provided at the bottom of the fixing groove (101); An expander (2), wherein the outer wall of the expander (2) is a cylindrical structure, a sample (3) is provided on the outer periphery of the expander (2), the expander (2) is located in the middle of the fixing groove (101), and one end of the expander (2) is detachably connected to the bottom of the fixing groove (101); A water injection pump, wherein the water outlet of the water injection pump is connected to one end of the first water injection channel (102) via a water injection pipe (103), and the water inlet of the water injection pump is connected to the water tank via a water delivery pipe; The sample (3) is cylindrical in structure, one end of the sample (3) is located on the steel base (1), one end of the expander (2) is provided with a water injection port (104), and the water injection port (104) is detachably connected to the other end of the first water injection channel (102); The expander (2) comprises: an expansion hole seat (21), the expansion hole seat (21) is located in the middle of the fixing groove (101), and one end of the expansion hole seat (21) is detachably connected to the bottom of the fixing groove (101); a sliding rod (22), the sliding rod (22) is located in the center of the expansion hole seat (21), and one end of the sliding rod (22) is fixedly connected to the other end of the expansion hole seat (21); and an inner lining steel wire rubber (23), the inner lining steel wire rubber (23) is a cylindrical structure, the inner lining steel wire rubber (23) is sleeved on the outer periphery of the sliding rod (22), and the inner lining steel wire rubber (23) is provided on the outer periphery of the sliding rod (22). One end of the wire rubber (23) is sealed and detachably connected to the other end of the expansion hole seat (21); a movable piston (24) is provided, the movable piston (24) is cylindrical in structure, the movable piston (24) is sleeved on the periphery of the sliding rod (22), the movable piston (24) is sealed and movably connected to the sliding rod (22), and one end of the movable piston (24) is sealed and detachably connected to the other end of the lined steel wire rubber (23); wherein the water injection port (104) is provided on the expansion hole seat (21); the sample (3) is sleeved on the periphery of the lined steel wire rubber (23).

2. The hole expansion test device according to claim 1, characterized in that: The expansion hole test device also includes a control system, which is connected to the water injection pump.

3. The hole expansion test device according to claim 2, characterized in that: The expansion hole test device further comprises a steel ring (4), the steel ring (4) being sleeved on the periphery of the steel wire rubber lining (23), the steel ring (4) being located above the sample (3), and one end of the steel ring (4) being in contact with and connected to the sample (3); the stiffness of the steel ring (4) being the same as that of the sample (3); and the maximum radial expansion hole pressure of the steel wire rubber lining (23) being 20 MPa.

4. The hole expansion test device according to claim 3, characterized in that: The inner diameter of the sample (3) is not greater than the inner diameter of the fixing groove (101), and the inner diameter of the sample (3) is greater than the outer diameter of the expansion hole seat (21); the outer diameter of the movable piston (24) is the same as the outer diameter of the expansion hole seat (21); and the inner diameter of the steel ring (4) is the same as the inner diameter of the sample (3).

5. The hole expansion test device according to claim 4, characterized in that: The expansion hole test device also includes: A plurality of displacement sensors, wherein the plurality of displacement sensors are evenly distributed on the outer side wall of the sample (3); A plurality of acoustic emission probes (5), wherein the plurality of acoustic emission probes (5) are evenly distributed on the outer wall of the sample (3); A high-speed camera, the high-speed camera being located outside the steel base (1), and the camera end of the high-speed camera being arranged opposite to the sample (3); an acoustic emission detector connected to a plurality of the acoustic emission probes; Among them, several of the displacement sensors, the high-speed cameras and the acoustic emission detectors are all connected to the control system.

6. The hole expansion test device according to claim 5, characterized in that: The expansion hole test device further comprises a pressure gauge (6), which is arranged at one end of the water injection pipe (103) close to the first water injection channel (102), and the pressure gauge (6) is connected to the control system.

7. A hole expansion test method, the hole expansion test method being used for the hole expansion test of the hole expansion test device according to claims 1 to 6, characterized in that: The expansion hole test method includes: Prepare specimens; The prepared sample is placed on the periphery of the steel wire rubber lining, and then a steel ring is placed on top of the sample; Arrange a displacement sensor on the outer wall of the sample, arrange an acoustic emission probe on the outer wall of the sample, and aim a high-speed camera at the sample; The displacement sensor, the acoustic emission probe, and the high-speed camera are turned on, and a water injection pump is controlled by a control system to inject water into the inner lining steel wire rubber to perform a hole expansion test; Recording the expansion pressure exerted on the sample during the water injection process, the radial displacement of the outer wall of the sample, the acoustic emission data, and the rupture of the sample along the axial direction of the hole to obtain the compressive strength of the sample under the action of the expansion, and obtaining the tensile strength of the sample based on the compressive strength; Analyze the circumferential and radial fracture characteristics of the sample, the relationship between the compressive strength and the deformation state of the sample, understand the cracking evolution process of the sample, and quantitatively analyze the radial stiffness evolution law of the sample after fracture.

8. A hole expansion test method according to claim 7, characterized in that: The sample preparation specifically includes: Drilling a cylindrical rock sample, polishing the inner and outer surfaces of the cylindrical rock sample to be smooth, and then fitting and fixing a steel sleeve tightly against the outer wall of the cylindrical rock sample to obtain the sample, wherein the stiffness of the sample is the same as the stiffness of the environment; or, A cylindrical mortar sample is obtained by casting mortar, and the inner and outer surfaces of the cylindrical mortar sample are polished smooth. Then, a steel sleeve is tightly fitted and fixed on the outer side wall of the cylindrical mortar sample to obtain the sample, and the stiffness of the sample is the same as the environmental stiffness.

9. A hole expansion test method according to claim 8, characterized in that: The steel sleeve is a cylindrical structure and includes two semi-cylinders, which are detachably connected by a plurality of bolts.

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