Indoor ground stress test equipment and method based on optical strain measurement

Abstract

The invention provides an indoor crustal stress test device and method based on optical strain measurement, the test device comprises a stress simulation device, the stress simulation device can perform real three-dimensional crustal stress environment simulation on a test rock mass as far as possible; the drilling releasing device is provided with a hollow drill bit used for drilling the optical strain measurer installed in the test rock mass, and the drilling hole and the hollow drill bit are coaxially arranged. Thus, according to the method, pressure is applied to the test rock mass from multiple directions through the multiple hydraulic loading columns, the real three-dimensional crustal stress environment can be more accurately simulated, speckle image changes in the speckle coating can be continuously recorded in real time through the optical strain measurer, and hole wall strain data are obtained; and converting the strain data into stress by applying an elastic theoretical formula, and accurately calculating the stress state of the experimental rock mass.

Description

Technical Field

[0001] The present invention relates to the technical field of rock mechanics testing equipment, and in particular to indoor ground stress testing equipment and method based on optical strain measurement. Background Art

[0002] Shallow mineral resources in my country are now being mined, and the country is moving towards deep resource mining. Deep engineering projects face a more complex and variable geostress environment than shallow ones. Dynamic hazards caused by geostress pose a serious threat to the safety of life and property of mining enterprises. Therefore, geostress measurement has become an important research topic in geotechnical engineering and mining. With the continuous development of geostress measurement technology, the stress relief method is currently a common measurement method, which can obtain relatively accurate geostress values. However, due to the inherent structural and principle limitations of the hollow inclusion strain gauges used in the test process, the obtained geostress results still contain some errors. Furthermore, during the tests, the stress applied to the test rock mass is mostly biaxial loading, simulating a two-dimensional stress environment. Drilling and stress relief cannot continuously simulate the true three-dimensional geostress environment. This undoubtedly leads to errors in the obtained geostress values. Such errors may affect the safety of engineering design and construction, as well as the stability of geotechnical engineering. Therefore, it is urgent to design a test device to address the shortcomings of current research. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to propose an indoor ground stress test device and method based on optical strain measurement, which is used to improve the accuracy of relevant data obtained during the test process, so as to at least partially solve the problems in the related art.

[0004] Based on the above objectives, the present invention provides an indoor ground stress test device based on optical strain measurement, comprising:

[0005] A stress simulation device includes a support platform and a reaction force assembly mounted on the support platform, wherein the support platform is provided with a placement position for placing a test rock mass, the test rock mass is provided with a mounting hole for mounting an optical strain gauge, the reaction force assembly is provided with openings for passing a hydraulic loading column at both ends thereof, which are arranged opposite to each other in a first direction, the reaction force assembly is provided with the opening for passing the hydraulic loading column at one end thereof, and the reaction force assembly is provided with a drill hole and the opening for passing the hydraulic loading column at both ends thereof, which are arranged opposite to each other in a second direction.

[0006] The release drilling device has a hollow drill bit for drilling the optical strain gauge installed in the installation hole, and the installation hole, the drilling hole and the hollow drill bit are coaxially arranged.

[0007] Optionally, the reaction force assembly includes a reaction force frame and a reaction force plate;

[0008] One end of the reaction frame is connected to the upper surface of the supporting platform, and the other end is connected to the reaction plate. The end of the reaction plate facing away from the reaction frame is connected to the supporting platform. The drilling hole is provided on the reaction plate, and the opening is provided on the end surface of the reaction frame facing away from the drilling hole.

[0009] Optionally, the reaction frame includes a fixed plate provided with the opening and a connecting beam for connecting the fixed plate and the reaction plate, the supporting platform is provided with a first plug-in slot for the fixed plate to be plugged in and a second plug-in slot for the reaction plate to be plugged in, the supporting platform is provided with a first threaded hole and a second threaded hole at two ends opposite to each other along the second direction, the fixed plate is provided with a first through hole corresponding to the first threaded hole, and the reaction plate is provided with a second through hole corresponding to the second threaded hole.

[0010] Optionally, the connecting beam includes a connecting rod and mounting members fixedly connected to both ends of the connecting rod;

[0011] The mounting member is provided with a clamping groove and a first through-hole for the screw to pass through, and the fixing plate and the reaction plate are both provided with a second through-hole corresponding to the first through-hole;

[0012] There are two connecting beams, and the two connecting beams are arranged opposite to each other along a first direction and are both arranged between the fixing plate and the reaction plate.

[0013] Optionally, the placement position is constructed as an open groove sunken into the upper surface of the supporting platform;

[0014] The two ends of the open groove that are opposite to each other along the second direction are respectively a channel opening and a positioning side wall surface.

[0015] Optionally, the invention further comprises a first force equalizing plate, wherein the number of the first force equalizing plates is two, and the two first force equalizing plates are respectively arranged at two ends of the open groove that are opposite to each other along the first direction;

[0016] A support plate is fixedly connected to one end of the first force equalizing plate close to the open groove, and receiving grooves for receiving the support plate are provided on two side walls of the open groove opposite to each other along the first direction;

[0017] A second force equalizing plate is further provided between the positioning side wall surface and the test rock mass, and the third force equalizing plate is placed on the upper surface of the test rock mass.

[0018] Optionally, a mobile component is also included;

[0019] The moving assembly includes a slide and a base, the slide is slidably connected to the base, and the release drilling device is installed on the upper surface of the slide;

[0020] The release drilling device includes a mounting frame, a drive motor, a first transmission assembly, a drive rod, a second transmission assembly, a drive rod, a reducer, a core sleeve and the hollow drill bit;

[0021] The output shaft of the drive motor is connected to the drive rod via the first transmission assembly, and the drive rod is connected to the transmission rod via the second transmission assembly. The end of the transmission rod facing away from the second transmission assembly is connected to the reducer, and the reducer is used to connect to the core sleeve. The end of the core sleeve facing away from the reducer is connected to the hollow drill bit.

[0022] The mounting frame is provided with a bearing seat for fixing the drive rod and the transmission rod. The mounting frame is also fixedly connected with an extension sleeve for supporting the core sleeve. A ring sleeve is provided on the inner wall surface of the extension sleeve. The core sleeve passes through the ring sleeve and a bearing is provided at the connection between the core sleeve and the ring sleeve.

[0023] Optionally, the first transmission assembly includes a first pulley connected to the output shaft of the drive motor and a second pulley installed on the drive rod, the first pulley and the second pulley are connected by a belt, and the second transmission assembly is constructed as a CVT continuously variable transmission mechanism.

[0024] Optionally, the optical strain meter includes a mounting frame, a shooting module and a lighting device, the shooting module and the lighting device are both mounted on the mounting frame, there are multiple shooting modules, and the multiple shooting modules are arranged at intervals along the length direction of the mounting frame, the shooting module includes a first mounting plate, a second mounting plate and a miniature camera, the first mounting plate and the second mounting plate are partially overlapped and fixedly connected, and there is an angle between the first mounting plate and the second mounting plate, the miniature camera is installed at both ends of the first mounting plate along its own length, and the miniature camera is installed at both ends of the second mounting plate along its own length, the mounting frame has multiple mounting surfaces, and one shooting module is installed on each mounting surface.

[0025] Based on the same inventive concept, the present application also provides an indoor ground stress test method based on optical strain measurement, which is applicable to any of the indoor ground stress test devices based on optical strain measurement described above, comprising:

[0026] Applying a speckle liquid to the inner wall surface of the mounting hole to form a speckle coating;

[0027] The optical strain gauge is mounted through the mounting hole, so that the optical strain gauge continuously captures and records images of the speckles in the speckle coating and an external image data processing computer continuously receives the acquired images;

[0028] The hydraulic loading column applies a preset stress to the test rock mass according to a preset stress value, thereby simulating the ground stress that the rock mass is subjected to in an actual scenario;

[0029] Relieving stress on the test rock mass by using the hollow drill bit, and then processing the recorded image by using the image data processing computer to obtain strain data;

[0030] The strain data is converted into a stress value according to an elasticity theory formula, the stress value is compared with the preset stress value, and the stress relief effect is evaluated based on the comparison result.

[0031] Through the above-mentioned technical solution, multiple hydraulic loading rods extend from multiple directions through openings in the reaction force assembly into the interior of the reaction force assembly, thereby contacting the test rock mass. This simulates a realistic three-dimensional geostress environment as closely as possible, ensuring that the data measured by the optical strain gauge installed in the test rock mass is closer to real data. Specifically, the optical strain gauge is installed in the test rock mass to ensure that it can continuously capture and record speckles in the speckle coating applied to the borehole wall, thereby obtaining corresponding borehole wall strain data. The strain data is converted into stress using elastic theory formulas, and the obtained stress is compared with the pre-applied stress to evaluate the stress relief effect. Simultaneously, this equipment can realistically simulate the stress relief technology used in on-site geostress testing in the laboratory, improving the accuracy of the optical strain gauge. The laboratory simulation results can provide a more accurate basis for on-site geotechnical engineering design, helping personnel to assess and predict risks caused by geostress changes, thereby improving the safety of construction workers.

[0032] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0034] Figure 1is a schematic structural diagram of an in-situ rock stress relief simulation test equipment provided in an exemplary embodiment of the present disclosure;

[0035] Figure 2 is a schematic front view of the structure of a stress simulation device provided in an exemplary embodiment of the present disclosure, wherein the connecting beam is not shown;

[0036] Figure 3 is a schematic side view of the structure of a stress simulation device provided in an exemplary embodiment of the present disclosure, wherein the connecting beam is not shown;

[0037] Figure 4 is a schematic structural diagram of a reaction force assembly and a supporting platform provided in an exemplary embodiment of the present disclosure;

[0038] Figure 5 1 is a schematic structural diagram of a supporting platform provided in an exemplary embodiment of the present disclosure and equipped with a fixing plate and a reaction plate;

[0039] Figure 6 is a structural schematic diagram of one angle of the supporting platform provided in an exemplary embodiment of the present disclosure;

[0040] Figure 7 is a structural schematic diagram of a carrying platform provided in an exemplary embodiment of the present disclosure and equipped with a first force equalizing plate;

[0041] Figure 8 is a schematic structural diagram of a first force equalizing plate provided in an exemplary embodiment of the present disclosure;

[0042] Figure 9 is a schematic structural diagram of a connecting beam provided in an exemplary embodiment of the present disclosure;

[0043] Figure 10 is a structural schematic diagram of a supporting platform provided in an exemplary embodiment of the present disclosure from another angle;

[0044] Figure 11 is a schematic structural diagram of a fixing plate provided in an exemplary embodiment of the present disclosure;

[0045] Figure 12 is a schematic structural diagram of a reaction plate provided in an exemplary embodiment of the present disclosure;

[0046] Figure 13 is a schematic structural diagram of an optical strain gauge provided in an exemplary embodiment of the present disclosure;

[0047] Figure 14 is a schematic structural diagram of a mounting bracket provided in an exemplary embodiment of the present disclosure;

[0048] Figure 153 is a flow chart of an indoor ground stress test method based on optical strain measurement provided in an exemplary embodiment of the present disclosure.

[0049] Description of Reference Numerals

[0050] 1-carrying platform; 101-first plug-in slot; 102-second plug-in slot; 103-first threaded hole; 104-second threaded hole; 105-open slot; 1051-channel opening; 1052-positioning side wall; 1053-storage slot; 2-reaction frame; 201-fixing plate; 2011-first through hole; 202-connecting beam; 2021-connecting rod; 2022-mounting piece; 20221-clamping slot; 20222-first through hole; 3-reaction plate; 301-drilling hole; 302-second through hole; 4-drilling device release; 401-mounting frame; 402-drive motor; 403-first transmission group Components; 4031-first pulley; 4032-second pulley; 404-driving rod; 405-second transmission assembly; 406-transmission rod; 407-reducing joint; 408-core sleeve; 409-hollow drill bit; 410-extension sleeve; 411-annular sleeve; 5-second perforation; 6-first force equalizing plate; 601-support plate; 7-second force equalizing plate; 8-third force equalizing plate; 9-moving assembly; 901-slide; 902-base; 10-test rock mass; 11-hydraulic loading column; 12-optical strain gauge; 1201-first mounting plate; 1202-second mounting plate; 1203-micro camera. DETAILED DESCRIPTION

[0051] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0052] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0053] Non-contact digital imaging (DIC) technology is a method for measuring material strain data. It analyzes deformation by comparing pixel displacements between two or more images. It is widely used in performance testing of rock, metal, and various organic materials. It not only requires low measurement conditions but also offers advantages such as simple data acquisition, non-contact operation, high measurement accuracy, and full-field measurement. Its non-contact nature protects data from many external influences, resulting in more accurate results.

[0054] In underground engineering, the borehole wall stress relief method is a commonly used technique for measuring in-situ stress and is currently a relatively accurate method for calculating in-situ stress data. The main principle is to completely or partially separate the rock sample from the surrounding rock mass by casing the borehole wall, while simultaneously monitoring the strain or displacement response of the relieved area. The in-situ in-situ stress is then determined based on the rock's constitutive relationship (the relationship between the relieved strain or displacement and the far-field stress of the surrounding rock). However, due to the inherent structural and principle limitations of traditional hollow-enclosed strain gauges, the in-situ stress results still contain some errors.

[0055] Based on this, in the specific embodiment provided in the present disclosure, an indoor ground stress test equipment based on optical strain measurement is provided, referring to Figures 1 to 15As shown, the indoor ground stress test equipment based on optical strain measurement includes: a stress simulation device and a drilling release device 4, wherein the stress simulation device can perform a more realistic three-dimensional ground stress environment simulation on the test rock mass 10, that is, the stress simulation device includes a bearing platform 1 and a reaction force component installed on the bearing platform 1, the bearing platform 1 is provided with a placement position for placing the test rock mass 10, both ends of the reaction force component opposite to each other along the first direction are provided with openings for the hydraulic loading column 11 to pass through, the two hydraulic loading columns 11 extend from the opposite sides of the first direction through the openings to the inside of the reaction force component and apply pressure to the test rock mass 10; an opening for the hydraulic loading column 11 to pass through is provided at the end of the reaction force component away from the placement position, that is, a hydraulic loading column 11 is provided above the placement position, and the hydraulic loading column 11 extends through the opening to the inside of the reaction force component and applies pressure to the test rock mass 10. The test rock mass 10 is exerted with pressure from above the reaction force component toward the placement position, and the placement position at this time will give the test rock mass 10 an upward reaction force; the two ends of the reaction force component that are relatively arranged along the second direction are respectively provided with a drilling hole 301 and an opening for the hydraulic loading column 11 to pass through, that is, the end of the reaction force component facing the release drilling device 4 should be provided with a drilling hole 301 for the hollow drill bit 409 to extend to the inside of the reaction force component, thereby ensuring that the hollow drill bit 409 can drill out the optical strain gauge 12 installed in the test rock mass 10. Therefore, the end of the reaction force component with the drilling hole 301 cannot be provided with the hydraulic loading column 11 for exerting pressure on the test rock mass 10, and a travel path needs to be reserved for the movement of the hollow drill bit 409. At the same time, an opening for the hydraulic loading column 11 to pass through can be provided at the end of the reaction force component away from the drilling hole 301, Figure 1 The hydraulic loading column 11 can be understood as applying pressure to the test rock mass 10 from the back thereof. At the same time, when the hydraulic loading column 11 located at the back of the test rock mass 10 applies pressure to it, the reaction force component can give the test rock mass 10 an opposite force. Based on this, reference Figure 1 and Figure 2 As shown, four hydraulic loading columns 11 apply pressure to the test rock mass 10 from above, to the left, to the right, and to the rear, respectively. A reaction force is also applied to the test rock mass 10 via the support platform 1 and the reaction force assembly, achieving a more realistic simulation of a three-dimensional geostress environment. This improves the accuracy of the measured data, minimizes data errors, and provides a more accurate basis for geotechnical engineering design. Simultaneously, the relief drilling device 4 includes a hollow drill bit 409 for drilling the optical strain gauge 12 installed in the test rock mass 10. Specifically, the optical strain gauge 12 is installed in the test rock mass 10 to continuously capture and record speckles in the speckle coating applied to the borehole wall, thereby acquiring corresponding borehole wall strain data. The strain data is converted into stress using elasticity theory formulas, and the obtained stress is compared with the pre-applied stress to evaluate the stress relief effect.

[0056] Through the above-described technical solution, multiple hydraulic loading columns 11 extend from multiple directions through openings in the reaction force assembly into the interior of the reaction force assembly, thereby contacting the test rock mass 10. This simulates a realistic three-dimensional geostress environment as closely as possible, ensuring that the data measured by the optical strain gauge 12 installed in the test rock mass 10 is closer to real data. Specifically, the optical strain gauge 12 is installed in the test rock mass 10 to ensure that it can continuously capture and record speckles in the speckle coating applied to the borehole wall, thereby acquiring corresponding strain data. The strain data is converted into stress using elastic theory formulas, and the obtained stress is compared with the pre-applied stress to evaluate the stress relief effect. Furthermore, this equipment can realistically simulate the stress relief technology used in on-site geostress testing in the laboratory, improving the accuracy of the optical strain gauge 12. The laboratory simulation results can provide a more accurate basis for on-site geotechnical engineering design, helping personnel to assess and predict risks caused by geostress changes, thereby improving the safety of construction workers.

[0057] Exemplarily, the first direction may be understood as the length direction of the carrying platform 1 , and the second direction may be understood as the width direction of the carrying platform 1 .

[0058] In some embodiments, reference Figures 4 to 10 As shown, the reaction force assembly includes a reaction frame 2 and a reaction plate 3, wherein one end of the reaction frame 2 is connected to the upper surface of the bearing platform 1, and the other end is connected to the reaction plate 3, and the end of the reaction plate 3 facing away from the reaction frame 2 is connected to the bearing platform 1, and a drilling hole 301 is provided on the reaction plate 3, and an opening is provided on the end surface of the reaction frame 2 facing away from the drilling hole 301, that is, when the hydraulic loading column 11 located on the back of the test rock mass 10 applies pressure to the test rock mass 10, the hydraulic loading column 11 extends to the inner side of the reaction frame 2 through the opening provided on the reaction frame 2 and then abuts against the test rock mass 10, thereby causing the reaction plate 3 and the test rock mass 10 to abut against each other and apply a reaction force thereto.

[0059] In some embodiments, reference Figures 4 to 10 As shown, the reaction frame 2 includes two parts, namely a fixed plate 201 with an opening and a connecting beam 202 for connecting the fixed plate 201 and the reaction plate 3. The fixed plate 201 and the connecting beam 202 are detachably connected, which is convenient for personnel to classify and store the fixed plate 201 and the connecting beam 202. When no measurement operation is required, the reaction frame 2 can be removed from the supporting platform 1 and the fixed plate 201 and the connecting beam 202 can be separated. This can significantly save storage space, especially when laboratory space is limited.

[0060] In some embodiments, reference Figures 4 to 10As shown, the supporting platform 1 is provided with a first plug-in slot 101 for the fixed plate 201 to be plugged in and a second plug-in slot 102 for the reaction plate 3 to be plugged in. The fixed plate 201 and the reaction plate 3 are installed on the supporting platform 1 by plugging. In order to ensure that the fixed plate 201 and the reaction plate 3 can be firmly installed on the supporting platform 1, a first threaded hole 103 and a second threaded hole 104 are respectively provided at the two ends of the supporting platform 1 that are opposite to each other along the second direction. A first through hole 2011 corresponding to the first threaded hole 103 is provided on the fixed plate 201, and a second through hole 2011 corresponding to the first threaded hole 103 is provided on the reaction plate 3. The second through hole 302 corresponding to the second threaded hole 104, that is, when the fixing plate 201 is inserted into the first insertion slot 101, the first through hole 2011 provided on the fixing plate 201 is coaxial with the first threaded hole 103, and at this time it is fixed by bolts so that the fixing plate 201 is firmly connected to the supporting platform 1; when the reaction plate 3 is inserted into the second insertion slot 102, the second through hole 302 provided on the reaction plate 3 is coaxial with the second threaded hole 104, and at this time it is fixed by bolts so that the reaction plate 3 is firmly connected to the supporting platform 1.

[0061] In some embodiments not shown in the figures, the connecting beam 202 includes a connecting column, the outer wall surface of which is provided with an external thread for threaded connection of a nut, the connecting column is arranged between the fixed plate 201 and the reaction plate 3, and the fixed plate 201 and the reaction plate 3 are provided with a through hole for the connecting column to pass through, and each connecting column is connected to four nuts, two nuts in a group, for clamping and fixing the fixed plate 201 and the reaction plate 3. At the same time, in order to ensure the stable connection of the nut, a washer can be provided on the connecting column, and each nut corresponds to at least one washer.

[0062] In some embodiments, reference Figures 4 to 12 As shown, the connecting beam 202 includes a connecting rod 2021 and mounting members 2022 fixedly connected to both ends of the connecting rod 2021. The mounting member 2022 is provided with a snap-in groove 20221 and a first through-hole 20222 for the screw to pass through. The fixed plate 201 and the reaction plate 3 are both provided with a second through-hole 5 corresponding to the first through-hole 20222. That is, during installation, the two mounting members 2022 located at both ends of the connecting rod 2021 should be aligned with the fixed plate 201 and the reaction plate 3 respectively, so that the snap-in groove 20221 on the mounting member 2022 can be plugged into the fixed plate 201 and the reaction plate 3. After the plugging is completed, the second through-hole 5 on the fixed plate 201 and the second through-hole 5 on the reaction plate 3 are respectively coaxial with the first through-hole 20222 of the corresponding mounting member 2022, and then are passed through by a screw and fixedly connected with the help of a nut.

[0063] In some embodiments, the snap-in groove 20221 can effectively increase the contact area between the mounting member 2022 and the fixed plate 201 and the reaction plate 3, thereby effectively increasing the connection strength between the connecting beam 202 and the fixed plate 201 and the reaction plate 3, so that the reaction plate 3 can better give a reaction force to the test rock mass 10, ensuring that a more realistic three-dimensional ground stress environment simulation can be given to the test rock mass 10.

[0064] In some embodiments, there are two connecting beams 202, the two connecting beams 202 are arranged opposite to each other along the first direction and the two connecting beams 202 are both arranged between the fixed plate 201 and the reaction plate 3, the fixed plate 201, the reaction plate 3 and the two connecting beams 202 together form an opening, so that the hydraulic loading column 11 located above the test rock mass 10 can extend from the opening to the inside of the reaction assembly and thereby apply pressure to the test rock mass 10.

[0065] In some embodiments, reference Figure 6 and Figure 10 As shown, the placement structure is an open groove 105 sunken into the upper surface of the supporting platform 1, wherein the two ends of the open groove 105 opposite to each other along the second direction are a passage opening 1051 and a positioning side wall surface 1052. The setting of the passage opening 1051 makes it convenient for personnel to transport the test rock mass 10 into the open groove 105. In order to ensure that the test rock mass 10 can be better pressurized by multiple hydraulic loading columns 11, the test rock mass 10 placed on the upper surface of the open groove 105 needs to be in a suitable position. In order to improve the work efficiency and placement accuracy when placing the test rock mass 10, the positioning side wall surface 1052 is used to position the test rock mass 10, that is, during the transportation of the test rock mass 10, the test rock mass 10 can be directly abutted against the positioning side wall surface 1052, and in order to further improve the placement accuracy, two marking lines can be marked on the positioning side wall surface 1052 according to the size of the test rock mass 10 itself. When placing, the test rock mass 10 should be between the two marking lines.

[0066] In some embodiments, reference Figure 7 and Figure 8 As shown, in order to enable the hydraulic loading column 11 to apply pressure to the test rock mass 10 more evenly, it can be implemented through the first force equalizing plate 6, that is, the number of the first force equalizing plates 6 is two, and the two first force equalizing plates 6 are respectively arranged at the two ends of the open groove 105 opposite to each other along the first direction. The two hydraulic loading columns 11 located on the test rock mass 10 and opposite to each other along the first direction respectively abut the test rock mass 10 through the first force equalizing plates 6 corresponding thereto. The first force equalizing plates 6 can evenly transfer the force applied by the hydraulic loading column 11 to the entire contact surface of the test rock mass 10, thereby avoiding local stress concentration.

[0067] In some embodiments, reference Figure 7 and Figure 8 As shown, the first force equalizing plate 6 can effectively and evenly transfer the force applied by the hydraulic loading column 11 to the entire contact surface of the test rock mass 10, thereby improving the accuracy of the data tested by the optical strain gauge 12 and making the test results more reliable. At the same time, the first force equalizing plate 6 can also protect the test rock mass 10 from direct high-pressure impact and reduce rock damage caused by uneven pressure. Therefore, before performing a three-dimensional ground stress environment simulation through the hydraulic loading column 11, the first force equalizing plate 6 needs to be in a suitable position to ensure that it can evenly transfer the force applied by the hydraulic loading column 11 to the entire contact surface of the test rock mass 10 to avoid affecting the accuracy of the test results. Based on this In order to save manpower and improve operational safety, a support plate 601 is fixedly connected to one end of the first force equalizing plate 6 close to the open groove 105. The angle between the support plate 601 and the connection part of the first force equalizing plate 6 is 90°. The support plate 601 can make the first force equalizing plate 6 stand upright on the upper surface of the open groove 105. Before the hydraulic loading column 11 applies pressure to the test rock mass 10, the position of the first force equalizing plate 6 can be adjusted by adjusting the placement of the support plate 601. The correct placement can ensure that the pressure applied to the test rock mass 10 is evenly distributed, making the measured data more reliable, facilitating subsequent data interpretation and analysis, and improving the accuracy of the test results.

[0068] In some embodiments, reference Figures 6 to 8 As shown, the open groove 105 has receiving grooves 1053 for receiving the support plate 601 on both side walls that are arranged opposite to each other along the first direction. That is, before performing three-dimensional ground stress environment simulation through the hydraulic loading column 11, the first force equalizing plate 6 can be arranged on the upper surface of the open groove 105. In order to ensure that the first force equalizing plate 6 can be stably placed in the open groove 105, the support plate 601 fixedly connected to the first force equalizing plate 6 can be inserted into the receiving groove 1053, and the support plate 601 is limited by the receiving groove 1053, so that the first force equalizing plate 6 is in an upright state and placed on the upper surface of the open groove 105.

[0069] In some embodiments, reference Figure 2 and Figure 3 As shown, in the present application, a second force equalizing plate 7 and a third force equalizing plate 8 are further provided, wherein the second force equalizing plate 7 is arranged between the positioning side wall surface 1052 and the test rock mass 10, and the second force equalizing plate 7 corresponds to the hydraulic loading column 11 located on the back of the test rock mass 10. The second force equalizing plate 7 enables the hydraulic loading column 11 located on the back of the test rock mass 10 to apply pressure to the test rock mass 10 more evenly; the third force equalizing plate 8 is placed on the upper surface of the test rock mass 10, and thus corresponds to the hydraulic loading column 11 located above the test rock mass 10. The third force equalizing plate 8 enables the hydraulic loading column 11 located above the test rock mass 10 to apply pressure to the test rock mass 10 more evenly.

[0070] In some embodiments, reference Figure 1 As shown, it also includes a moving component 9, wherein the moving component 9 includes a slide 901 and a base 902, the slide 901 is slidably connected to the base 902, and a release drilling device 4 is installed on the upper surface of the slide 901, that is, the slide 901 can drive the release drilling device 4 to move along the length direction of the base 902, so that the hollow drill bit 409 can extend through the drilling hole 301 to the inside of the reaction force component and then contact the test rock mass 10, thereby drilling out the optical strain gauge 12 installed in the test rock mass 10.

[0071] In some embodiments not shown in the figures, a slide rail is fixedly connected to the base 902, a slider matching the slide rail is provided at the bottom of the slide 901, and a driving device for driving the base 902 to move is installed on the base 902. The driving device can be a cylinder or a hydraulic cylinder, and the output end of the driving device is connected to the slide 901.

[0072] In some embodiments not shown in the figures, the slide 901 and the base 902 can be a ball screw slide 901, that is, two support shaft seats are installed on the base 902, and the screw shaft is installed between the support shaft seats. One end of the screw shaft is connected to the output shaft of the motor through a coupling, and a screw nut is installed on the screw shaft. The slide 901 and the screw nut are detachably connected. A guide rail is also provided on the base 902, and a guide rail block matching the guide rail is provided on the lower surface of the slide 901. The screw shaft is driven by the driving motor 402 to rotate, so that the screw nut moves linearly along the length direction of the screw shaft. By controlling the forward and reverse rotation of the motor output shaft, the screw nut can be reciprocated along the length direction of the screw shaft. When moving, the screw nut can synchronously drive the slide 901 to move, thereby releasing the movement of the drilling device 4, thereby drilling out the optical strain gauge 12 installed in the test rock mass 10.

[0073] In some embodiments, reference Figure 1As shown, the release drilling device 4 includes a mounting frame 401, a drive motor 402, a first transmission assembly 403, a drive rod 404, a second transmission assembly 405, a drive rod 406, a reducer 407, a core sleeve 408 and a hollow drill bit 409, wherein the output shaft of the drive motor 402 is connected to the drive rod 404 via the first transmission assembly 403, the drive rod 404 and the drive rod 406 are connected via the second transmission assembly 405, the end of the drive rod 406 away from the second transmission assembly 405 is connected to the reducer 407, the reducer 407 is used to connect the core sleeve 408, and the end of the core sleeve 408 away from the reducer 407 is connected to the hollow drill bit 409, that is, the output shaft of the drive motor 402 is connected to the core sleeve 408 via the transmission of the first transmission assembly 403. The drive rod 404 can be rotated. When the drive rod 404 rotates, the drive rod 404 can rotate the transmission rod 406 through the second transmission assembly 405. One end of the transmission rod is connected to the core sleeve 408 and the hollow drill bit 409 via the reducer 407. Therefore, the transmission rod 406 can drive the core sleeve 408 and the hollow drill bit 409 to rotate. When it is necessary to remove the optical strain gauge 12 installed in the test rock mass 10, the moving assembly 9 can be activated, so that the slide 901 drives the entire release drilling device 4 to move, allowing the hollow drill bit 409 to contact the test rock mass 10 through the drilling hole 301 and begin the drilling operation. The removed optical strain gauge 12 and the portion of rock mass wrapped around the optical strain gauge 12 are located within the core sleeve 408.

[0074] In some embodiments, reference Figure 1 As shown, in order to enable the driving rod 404 and the transmission rod 406 to rotate stably, a bearing seat for fixing the driving rod 404 and the transmission rod 406 can be provided on the mounting frame 401. At the same time, in order to enable the core sleeve 408 to rotate stably, an extension sleeve 410 for supporting the core sleeve 408 is also fixed to the mounting frame 401. A ring sleeve 411 is provided on the inner wall surface of the extension sleeve 410. The core sleeve 408 is passed through the ring sleeve 411 and a bearing is provided at the connection between the core sleeve 408 and the ring sleeve 411, that is, the extension sleeve 410 and the ring sleeve 411 support the core sleeve 408. The bearing provided at the connection between the core sleeve 408 and the ring sleeve 411 can reduce the friction between the sleeve and the core sleeve 408, so that the core sleeve 408 can rotate more smoothly.

[0075] In some embodiments, reference Figure 1 As shown, the first transmission assembly 403 includes a first pulley 4031 connected to the output shaft of the driving motor 402 and a second pulley 4032 installed on the driving rod 404, and the first pulley 4031 and the second pulley 4032 are connected by a belt.

[0076] In some embodiments not shown, the first transmission assembly 403 includes a first sprocket connected to the output shaft of the driving motor 402 and a second sprocket mounted on the driving rod 404 , and the first sprocket and the second sprocket are connected by a chain.

[0077] Similarly, the second transmission component 405 can also be belt driven or chain driven.

[0078] In some embodiments, reference Figure 1 As shown, the second transmission assembly 405 is constructed as a CVT continuously variable transmission mechanism. That is, when the downhole ground stress test is truly reproduced in the laboratory, many factors such as the drilling speed of the hollow drill bit 409 when drilling the optical strain gauge 12 and the rotation speed of the hollow drill bit 409 may cause the measured relevant values ​​to have errors compared with the actual values. In order to reduce the error value, the CVT continuously variable transmission mechanism can be used to overcome the problem of the hollow drill bit 409 rotating speed being reduced due to resistance when the hollow drill bit 409 contacts the test rock mass 10, thereby ensuring that the entire drilling process is as stable as possible. Both the driving rod 404 and the transmission rod 406 are provided with a reducing gear, and the two reducing gears are connected by a steel belt transmission. At the same time, a hydraulic component can be installed on the upper surface of the slide 901 (the hydraulic component includes a hydraulic pump, a hydraulic cylinder and a control valve, wherein the hydraulic pump provides hydraulic power to deliver hydraulic oil to the hydraulic cylinder of the reducing gear; the hydraulic cylinder is connected to the reducing gear, and the pressure of the hydraulic oil is used to push or pull the gear, thereby changing its diameter; the control valve is used to adjust the flow direction and pressure of the hydraulic oil to accurately control the diameter change of the reducing gear.) to facilitate the control and adjustment of the reducing gear.

[0079] In some embodiments, when drilling the optical strain gauge 12 through the hollow drill bit 409, a water spray cooling device may be provided to prevent the surrounding rock from being fractured due to excessively high temperatures during drilling, wherein the water spray pipe of the water spray cooling device is aimed at the drilling site, thereby reducing the temperature during drilling.

[0080] Instructions for use of the equipment: Before the test, the test rock mass 10 needs to be placed on the upper surface of the open groove 105 and the first equalizing plate 6, the second equalizing plate 7 and the third equalizing plate 8 need to be placed in appropriate positions in turn, and then the reaction assembly needs to be installed, that is, the fixed plate 201 and the reaction plate 3 are respectively inserted into the first plug-in slot 101 and the second plug-in slot 102, and then the fixed plate 201 and the reaction plate 3 are fixed by bolts, and then the connecting beam 202 is installed between the fixed plate 201 and the reaction plate 3. The fixed plate 201 and the reaction plate 3 partially overlap with the mounting piece 2022 through the clamping slot 20221 to increase the connection strength; before drilling, it is necessary to ensure that the hollow drill bit 409 can contact the test rock mass 10 through the drilling hole 301 on the reaction plate 3, and then drill the optical strain meter 12 installed inside it.

[0081] For description of the optical strain gauge 12: Figure 13 and Figure 14 As shown, the optical strain gauge 12 includes a mounting frame, a camera module, and an illumination device. The illumination device is used to fill light inside the mounting hole, so that the camera module can clearly and continuously capture and record the speckle in the speckle coating applied on the hole wall of the mounting hole. The camera module and the illumination device are both mounted on the mounting frame. Exemplarily, there are multiple camera modules, which are arranged at intervals along the length of the mounting frame. The camera module includes a first mounting plate 1201, a second mounting plate 1202, and a micro camera 1203. The first mounting plate 1201 and the second mounting plate 1202 are connected to each other. The mounting plates 1202 are partially overlapped and fixedly connected, and there is an angle between the first mounting plate 1201 and the second mounting plate 1202. The first mounting plate 1201 is mounted with a micro camera 1203 at both ends along its length, and the second mounting plate 1202 is mounted with a micro camera 1203 at both ends along its length. The mounting frame has multiple mounting surfaces, and each mounting surface is mounted with a shooting module. For ease of understanding, the outer contour of the mounting frame is an equilateral triangle. Each group of shooting modules has four micro cameras 1203, and the focus of the four micro cameras 1203 in each group will be concentrated on one point, that is, reference Figure 13 As shown, there are three focal points A, B, and C, and each group of shooting modules corresponds to one focal point.

[0082] Exemplarily, the image data processing computer includes a DIC image data processing computer, wherein the DIC image data processing computer has built-in three-dimensional DIC image processing software and ground stress calculation software. The three-dimensional DIC image processing software can reconstruct the collected surface images into a three-dimensional strain data model.

[0083] The optical strain gauge 12 also includes a glass cover, a power supply unit, a connector, a data storage and transmission unit, and a remote control unit. The glass cover is used for protection and is located outside the mounting frame. Multiple lighting devices can be provided according to actual needs, and multiple lighting devices are arranged at intervals on the mounting frame. The angle between the first mounting plate 1201 and the second mounting plate 1202 is 45 degrees. The power supply unit can provide power support for the micro camera 1203 and the illumination light source in the DIC image data collector to maintain stable operation of the system. Its data storage and transmission unit can transmit the DIC image data recorded by the micro camera 1203 to the DIC image data processing computer. Its storage function can also prevent image loss caused by poor signal in the mounting hole. By storing images, it is convenient for later inspection. The remote control unit uses wireless transmission technology to adjust the brightness of the internal illumination light source and perform camera zoom operations.

[0084] For example, taking the micro camera 1203 installed on the first mounting plate 1201 as an example, the two micro cameras 1203 on the first mounting plate 1201 are symmetrically arranged and the lens angle of the micro camera 1203 has an angle of 15° with the central axis of the micro camera 1203 body. The same is true for the micro camera 1203 on the second mounting plate 1202, so that the focus of each group of four micro cameras 1203 will be concentrated on one point.

[0085] Exemplarily, the image data captured by the micro camera 1203 are transmitted via Bluetooth transmission technology to a DIC image data processing computer terminal for real-time observation and remote control via Bluetooth.

[0086] The principle of 3D DIC full-field strain measurement is to create randomly distributed, high-contrast speckles on the surface of the measured area. By capturing the movement of speckle features at the pixel level and using optimized 3D digital image correlation algorithms, a method for measuring morphology, displacement, and strain data in the full field of view of the three-dimensional space is provided for the experiment. This method is generally divided into four steps: speckle creation, system calibration, strain measurement, and image analysis. To obtain strain on a curved surface, dual micro-cameras 1203 (two micro-cameras 1203 on the first mounting plate 1201 or the second mounting plate 1202 are positioned at an angle of 15° to the central axis of the micro-camera 1203 body) are used to monitor the measured area. Algorithmic corrections are then used to perform a three-dimensional reconstruction of the surface strain. This technique can obtain horizontal and vertical strains on the curved surface. Because geostress has maximum, intermediate, and minimum principal stresses at different azimuth angles, strains in two additional directions are required to obtain strains in four different directions. By setting the positional relationship of the micro-cameras 1203, the two micro-cameras 1203 are arranged symmetrically. Using the micro-cameras 1203 at different angles in the camera holder, the coordinates of the same point can be indirectly converted, thereby obtaining two strains at an angle of 45° to the horizontal and vertical strains. Therefore, four sets of strain data in different directions can be obtained at a single measurement point (focus A, focus B, or focus C). Another advantage of non-contact three-dimensional strain optical measurement technology is that it can measure the full-field strain on the entire surface, rather than being limited to a single measurement point, which can obtain more data calculations and thus reduce calculation errors. Figure 13 As shown, the present invention divides the entire measurement space into three strain regions along the axial and circumferential directions in the measurement area, and takes a point in each of the three regions as a measurement point (focus A, focus B, or focus C). Among them, focus A, focus B, and focus C are spaced apart along the depth direction of the mounting hole, thereby forming three strain regions. After the DIC image is post-processed by the DIC image data processing computer, a total of 12 sets of strain data are obtained. Finally, the ground stress data is obtained by the formula built into the ground stress calculation software in the DIC image data processing computer.

[0087] Based on the same inventive concept, Figure 15 As shown, the present application also provides an indoor ground stress test method based on optical strain measurement, which is applicable to any of the above-mentioned indoor ground stress test equipment based on optical strain measurement, comprising the following steps:

[0088] Step 101 : spray-coating the mounting hole on the test rock mass 10 for mounting the optical strain gauge 12 , so that the mounting hole is covered with a layer of speckle coating. The speckle on the speckle coating is used for the micro camera 1203 to capture its speckle characteristics.

[0089] Step 102: After the spraying is completed and the coating is dry, the optical strain gauge 12 is installed in the mounting hole, so that the optical strain gauge continuously captures and records the speckle in the speckle coating and the external image data processing computer continuously receives the acquired image.

[0090] Step 103: Apply a preset ground stress to the test rock mass 10 using the aforementioned indoor ground stress test equipment based on optical strain measurement. At this point, the micro camera 1203 is required to capture speckle patterns and capture speckle features (recording speckle strain images before stress release, with three measurement points recorded separately by three sets of camera modules). Then, the optical strain gauge 12 is de-stressed by releasing the drilling device 4. During the de-stressing process, the micro camera 1203 also records speckle features in real time. The image data recorded by the micro camera 1203 is transmitted to a DIC image data processing computer via a data storage and transmission unit. The recorded images are then processed by the DIC image data processing computer. The DIC images of the three groups of measurement points before stress release are converted into initial strain data by the DIC image data processing computer. ; Convert the DIC image after stress relief is completed into the final relief strain data. Specifically, taking one group of shooting modules as an example, the DIC images recorded by the two micro cameras 1203 installed on the first mounting plate 1201 will obtain a horizontal strain and a vertical strain after being processed by the DIC image data processing computer. For ease of understanding, the horizontal strain and the vertical strain are defined as the first direction strain and the second direction strain. Since there is a 45° angle between the first mounting plate 1201 and the second mounting plate 1202, the DIC images recorded by the two micro cameras 1203 installed on the second mounting plate 1202 will obtain the third direction strain and the fourth direction strain after being processed by the DIC image data processing computer. Similarly, strain data in 12 directions are obtained at the three measuring points (focus A, focus B, and focus C).

[0091] In some embodiments, mechanical parameter measurements are performed, the test rock mass 10 is processed and subjected to basic mechanical tests to obtain the elastic modulus and Poisson's ratio of the test rock mass 10 .

[0092] Step 104 : Convert the strain data in the 12 directions into stress values ​​according to elasticity theory formulas, compare the stress values ​​with preset stress values, and evaluate the stress relief effect based on the comparison results.

[0093] The specific formula is as follows:

[0094] E[Δε1Δε2Δε3Δε 4··· Δε 12 ] T =M×[σ' x σ' y σ' z τ xy τ yz τ zx ] T

[0095]

[0096] Where E is the elastic modulus of the rock sample; the matrix M is the coefficient matrix for solving the stress components according to the strain data directions obtained by different optical strain measurement devices; v is the Poisson's ratio of the rock sample;

[0097] For example, for the monitoring angles of the three groups of shooting modules, for ease of understanding, the positive direction of the horizontal Y-axis is set to 0°. At this time, the monitoring angles of the three groups of shooting modules are 90°, -30° and -150° respectively.

[0098] The preset stress value is the stress applied by the hydraulic loading column 11, refer to Figures 2 to 4 As shown, for ease of understanding, three-axis coordinates are established, including X, Y, and Z directions, where the Z direction (maximum principal stress direction) is perpendicular to the carrier platform, the Y direction (intermediate principal stress direction) is along the length of the carrier platform 1, and the X direction (minimum principal stress direction) is along the mounting hole direction. Based on this, σ x , σ y , σ z That is, the minimum principal stress, the intermediate principal stress and the maximum principal stress; σ x , σ y , σ z are the preset stress values ​​in three directions.

[0099] ε n is the initial strain before release, ε' n is the final strain after release, Δε n =ε' n -ε n Based on this, the initial strain data in the above 12 directions are ε1, ε2, ε3, ε4, ε5, ε6, ε7, ε8, ε9, ε10 , ε 11 , ε 12 The final strain relief data in the above 12 directions are ε'1, ε'2, ε'3, ε'4, ε'5, ε'6, ε'7, ε'8, ε'9, ε' 10 、ε' 11 、ε' 12 , taking ε1 as an example, Δε1=ε'1-ε1;

[0100] The six stress components are σ' x ,σ' y ,σ' z , τ xy , τ yz , τ zx， Among them, τ xy represents the shear stress acting on the x-plane and along the y-direction, τ yz represents the shear stress acting on the y surface and along the z direction, τ zx represents the shear stress acting on the z-plane and along the x-direction, where σ' x ,σ' y ,σ' z The strain data is obtained by the optical strain gauge 12 and then solved by combining with the elasticity theory formula.

[0101] Step 105: Process the recorded image using a DIC image data processing computer, convert the image into real-time strain data during the stress relief process, and plot the real-time strain data into a strain-relief footage curve. By observing the fitting of the strain-relief footage curve, if the data curves in more than 10 of the twelve directions are relatively smooth, the stress relief effect is excellent; if the data curves in more than 8 directions are relatively smooth, the stress relief effect is good; if the data curves in more than 6 directions are relatively smooth, the stress relief effect is moderate; and if the data curves in less than 6 directions are relatively smooth, the stress relief effect is poor.

[0102] In addition to observing the data curve, the extracted core can also be checked for breakage. During the coring process, if the hollow drill bit has a small aperture or the drill bit has been drilled for a long time, there is a high probability that the core will break during the contact process. Therefore, if this does not happen, the coring process is considered to be effective; otherwise, the coring effect is poor.

[0103] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present disclosure (including the claims) is limited to these examples. Within the scope of the present invention, the above embodiments or technical features in different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0104] The embodiments of the present invention are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An indoor ground stress test equipment based on optical strain measurement, characterized in that: include: A stress simulation device comprises a bearing platform (1) and a reaction force component mounted on the bearing platform (1), wherein the bearing platform (1) is provided with a placement position for placing a test rock mass (10), the test rock mass (10) is provided with a mounting hole for mounting an optical strain gauge (12), both ends of the reaction force component arranged opposite to each other in a first direction are provided with openings for a hydraulic loading column (11) to pass through, an end of the reaction force component away from the placement position is provided with the opening for the hydraulic loading column (11) to pass through, and both ends of the reaction force component arranged opposite to each other in a second direction are provided with a drilling hole (301) and the opening for the hydraulic loading column (11) to pass through. The release drilling device (4) has a hollow drill bit (409) for drilling the optical strain gauge (12) installed in the installation hole, and the installation hole, the drilling hole (301) and the hollow drill bit (409) are coaxially arranged.

2. The indoor ground stress test equipment based on optical strain measurement according to claim 1, characterized in that: The reaction force assembly comprises a reaction force frame (2) and a reaction force plate (3); One end of the reaction frame (2) is connected to the upper surface of the bearing platform (1), and the other end is connected to the reaction plate (3); the end of the reaction plate (3) facing away from the reaction frame (2) is connected to the bearing platform (1); the reaction plate (3) is provided with the drilling hole (301); and the end surface of the reaction frame (2) facing away from the drilling hole (301) is provided with the opening.

3. The indoor ground stress test equipment based on optical strain measurement according to claim 2, characterized in that: The reaction frame (2) comprises a fixing plate (201) provided with the opening and a connecting beam (202) for connecting the fixing plate (201) and the reaction plate (3); the bearing platform (1) is provided with a first plug-in slot (101) for plugging the fixing plate (201) and a second plug-in slot (102) for plugging the reaction plate (3); two ends of the bearing platform (1) arranged opposite to each other along the second direction are respectively provided with a first threaded hole (103) and a second threaded hole (104); the fixing plate (201) is provided with a first through hole (2011) corresponding to the first threaded hole (103); and the reaction plate (3) is provided with a second through hole (302) corresponding to the second threaded hole (104).

4. The indoor ground stress test equipment based on optical strain measurement according to claim 3 is characterized in that: The connecting beam (202) comprises a connecting rod (2021) and mounting parts (2022) fixedly connected to both ends of the connecting rod (2021); The mounting member (2022) is provided with a snap-fitting groove (20221) and a first through hole (20222) for the screw to pass through, and the fixing plate (201) and the reaction plate (3) are both provided with a second through hole (5) corresponding to the first through hole (20222); The number of the connecting beams (202) is two, the two connecting beams (202) are arranged opposite to each other along a first direction, and the two connecting beams (202) are both arranged between the fixing plate (201) and the reaction plate (3).

5. The indoor ground stress test equipment based on optical strain measurement according to claim 1, characterized in that: The placement position is structured as an open groove (105) sunken into the upper surface of the support platform (1); Two ends of the open groove (105) that are arranged opposite to each other along the second direction are respectively a channel opening (1051) and a positioning side wall surface (1052).

6. The indoor ground stress test equipment based on optical strain measurement according to claim 5, characterized in that: It also includes a first force equalizing plate (6), the number of the first force equalizing plates (6) is two, and the two first force equalizing plates (6) are respectively arranged at two ends of the open groove (105) that are arranged opposite to each other along the first direction; A support plate (601) is fixedly connected to one end of the first force equalizing plate (6) close to the open groove (105), and receiving grooves (1053) for receiving the support plate (601) are provided on two side walls of the open groove (105) arranged opposite to each other along the first direction; A second force equalizing plate (7) is also provided between the positioning side wall surface (1052) and the test rock mass (10), and a third force equalizing plate (8) is placed on the upper surface of the test rock mass (10).

7. The indoor ground stress test equipment based on optical strain measurement according to claim 1, characterized in that: Also includes a moving component (9); The moving assembly (9) comprises a slide (901) and a base (902), the slide (901) being slidably connected to the base (902), and the release drilling device (4) is mounted on the upper surface of the slide (901); The release drilling device (4) comprises a mounting frame (401), a drive motor (402), a first transmission assembly (403), a drive rod (404), a second transmission assembly (405), a transmission rod (406), a reducer (407), a core sleeve (408) and the hollow drill bit (409); The output shaft of the driving motor (402) is connected to the driving rod (404) via the first transmission assembly (403), the driving rod (404) is connected to the transmission rod (406) via the second transmission assembly (405), the end of the transmission rod (406) away from the second transmission assembly (405) is connected to the reducer (407), the reducer (407) is used to connect to the core sleeve (408), and the end of the core sleeve (408) away from the reducer (407) is connected to the hollow drill bit (409); The mounting frame (401) is provided with a bearing seat for fixing the driving rod (404) and the transmission rod (406); the mounting frame (401) is also fixedly connected with an extension sleeve (410) for supporting the core sleeve (408); a ring sleeve (411) is provided on the inner wall surface of the extension sleeve (410); the core sleeve (408) is penetrated by the ring sleeve (411), and a bearing is provided at the connection portion between the core sleeve (408) and the ring sleeve (411).

8. The indoor ground stress test equipment based on optical strain measurement according to claim 7, characterized in that: The first transmission assembly (403) includes a first pulley (4031) connected to the output shaft of the driving motor (402) and a second pulley (4032) installed on the driving rod (404), the first pulley (4031) and the second pulley (4032) are connected by a belt, and the second transmission assembly (405) is constructed as a CVT continuously variable transmission mechanism.

9. The indoor ground stress test equipment based on optical strain measurement according to claim 1, characterized in that: The optical strain gauge (12) comprises a mounting frame, a photographing module and an illumination device, wherein the photographing module and the illumination device are both mounted on the mounting frame, the number of the photographing modules is multiple, and the multiple photographing modules are arranged at intervals along the length direction of the mounting frame, the photographing module comprises a first mounting plate (1201), a second mounting plate (1202) and a micro camera (1203), the first mounting plate (1201) and the second mounting plate (1202) are partially overlapped and fixedly connected, and an angle is formed between the first mounting plate (1201) and the second mounting plate (1202), the micro cameras (1203) are mounted at both ends of the first mounting plate (1201) along its own length, and the micro cameras (1203) are mounted at both ends of the second mounting plate (1202) along its own length, and the mounting frame has multiple mounting surfaces, and one photographing module is mounted on each mounting surface.

10. An indoor geostress test method based on optical strain measurement, applicable to the indoor geostress test equipment based on optical strain measurement according to any one of claims 1 to 9, characterized in that: include: Applying a speckle liquid to the inner wall surface of the mounting hole to form a speckle coating; The optical strain gauge (12) is mounted through the mounting hole, so that the speckle in the speckle coating is continuously imaged and recorded by the optical strain gauge (12) and the acquired image is continuously received by an external image data processing computer; The hydraulic loading column (11) applies a preset stress to the test rock mass (10) according to a preset stress value, thereby simulating the ground stress borne by the rock mass in an actual scene; The test rock mass (10) is subjected to stress relief by means of the hollow drill bit (409), and then the recorded image is subjected to data processing by means of the image data processing computer to obtain strain data; The strain data is converted into a stress value according to an elastic theory formula, the stress value is compared with the preset stress value, and the stress relief effect is evaluated based on the comparison result.

Images