Abstract: A system and a method for monitoring overlying roof rock and coal pillar in gob-side entry are provided. The system includes top monitoring stations, coal pillar comprehensive monitoring stations, roof stress monitoring stations, and a master computer. Top monitoring stations are arranged in the crossheading to monitor the working face, coal pillar comprehensive monitoring stations are arranged in the upper roadway of the lower coal seam working face to monitor the coal pillars, and roof stress monitoring stations are arranged in the mining area main roadway to monitor the coal pillars. Monitoring the stress and deformation distribution of coal pillars in the goaf and the movement and failure process of overburden strata structure through the master computer control each monitoring station. The monitoring stations ensure that the overburden strata movement monitoring stations are still in working condition after the goaf is formed by mining in the working face.

Abstract: A multi-stage pressure yielding and anti-impact device for anchoring support is proposed, which includes an anti-impact component, a secondary pressure yielding component, and a primary pressure yielding component. The primary pressure yielding component and the secondary pressure yielding component each include an outer sleeve, an inner extrusion sleeve, and an expansion platform, and the expansion platform is arranged at a bottom end of the inner extrusion sleeve. A buffering and energy-absorbing material filling body is arranged between the outer sleeve and the inner extrusion sleeve. An outside diameter of the outer sleeve in the primary pressure yielding component is equal to that of a large-diameter end of the expansion platform in the secondary pressure yielding component, and the outer sleeve in the primary pressure yielding component is pressed against a bottom of the expansion platform in the secondary pressure yielding component.

Abstract: A multi-stage pressure yielding and anti-impact device for anchoring support is proposed, which includes an anti-impact component, a secondary pressure yielding component, and a primary pressure yielding component. The primary pressure yielding component and the secondary pressure yielding component each include an outer sleeve, an inner extrusion sleeve, and an expansion platform, and the expansion platform is arranged at a bottom end of the inner extrusion sleeve. A buffering and energy-absorbing material filling body is arranged between the outer sleeve and the inner extrusion sleeve. An outside diameter of the outer sleeve in the primary pressure yielding component is equal to that of a large-diameter end of the expansion platform in the secondary pressure yielding component, and the outer sleeve in the primary pressure yielding component is pressed against a bottom of the expansion platform in the secondary pressure yielding component.

Abstract: The present disclosure provides a test system and method for an anchoring performance of a full-size rock mass anchor bolt under combined load and relates to the technical field of detection test equipment. The system includes a primary frame, a co-directional pull-twist loading mechanism and a vertical shear loading mechanism. The primary frame includes a dual-parallel horizontal reaction frame and a vertical reaction frame. The co-directional pull-twist loading mechanism and the vertical shear loading mechanism are arranged in synergy with the primary frame. The co-directional pull-twist loading mechanism performs synchronous pull and twist loading for the anchored rock mass and the vertical shear loading mechanism applies a static load or simulates a dynamic load disturbance. The co-directional pull-twist loading mechanism and the vertical shear loading mechanism perform separate loading.

Abstract: A test system for an anchoring performance of a full-size rock mass anchor bolt under combined load and relates to the technical field of detection test equipment includes a primary frame, a co-directional pull-twist loading mechanism and a vertical shear loading mechanism. The primary frame includes a dual-parallel horizontal reaction frame and a vertical reaction frame. The co-directional pull-twist loading mechanism and the vertical shear loading mechanism are arranged in synergy with the primary frame. The co-directional pull-twist loading mechanism performs synchronous pull and twist loading for the anchored rock mass and the vertical shear loading mechanism applies a static load or simulates a dynamic load disturbance. The co-directional pull-twist loading mechanism and the vertical shear loading mechanism perform separate loading.

Abstract: A drilling device for coal mining is provided, including a placement board. The placement board is fixedly connected to a first support pillar and a second support pillar, and the first support pillar and the second support pillar are together fixedly connected to a transmission rod; the transmission rod is connected to support rods symmetrically distributed in a limited sliding manner, and the support rods symmetrically distributed are connected to a connecting rod in a sliding manner; the connecting rod is provided with grooves evenly distributed in a circumferential direction, the grooves are fixedly connected to pneumatic telescopic blocks, and the telescopic end of each pneumatic telescopic block is fixedly connected to an arc-shaped plate. The arc-shaped plate is extended in a circumferential direction to support the drilled hole close to the drill bit, preventing the collapse of the drilling wall close to the drill bit.

Abstract: A three-dimensional dynamic and static load test system for simulating deep roadway excavation and a method thereof are provided, which relates to the technical field of indoor simulation testing in underground engineering. The system includes a mobile platform, a box body, a support frame, a roadway excavation device, and a data monitoring unit. The system and method of the disclosure can reproduce the whole process of roadway excavation, simulate the multi-directional loading of deep roadway, and restore the real stress state of deep roadway under the influence of dynamic and static load superimposed disturbance. The problem of insufficient research under the condition of unidirectional static loading and lack of multi-directional dynamic and static loading in current large-scale experimental devices has been solved, and the stress and deformation of the surrounding rock of the roadway are reflected in real-time through the data monitoring unit.

Abstract: A collaborative erosion-control method of releasing-splitting-supporting based on coal mass pressure relief and roof pre-splitting provided by the disclosure includes the following steps: step 1, driving into a coal seam to release pressure; step 2, low roof pre-splitting during driving process; step 3, supporting of roadway surrounding rock and support reinforcement; step 4, floor destressing of the roadway; step 5, high roof pre-splitting before mining; step 6, destressing and supporting of the advanced roadway surrounding rock during the mining process of the working face. The collaborative erosion-control method of releasing-splitting-supporting based on coal mass pressure relief and roof pre-splitting, and to carry out local pressure relief, roof pre-splitting and reinforcement support construction in the whole cycle of the coal working face in a progressive manner, so as to achieve the prevention and control of rock burst in the working face.

Abstract: A collaborative erosion-control method of releasing-splitting-supporting based on coal mass pressure relief and roof pre-splitting provided by the disclosure includes the following steps: step 1, driving into a coal seam to release pressure; step 2, low roof pre-splitting during driving process; step 3, supporting of roadway surrounding rock and support reinforcement; step 4, floor destressing of the roadway; step 5, high roof pre-splitting before mining; step 6, distress sing and supporting of the advanced roadway surrounding rock during the mining process of the working face. The collaborative erosion-control method of releasing-splitting-supporting based on coal mass pressure relief and roof pre-splitting, and to carry out local pressure relief, roof pre-splitting and reinforcement support construction in the whole cycle of the coal working face in a progressive manner, so as to achieve the prevention and control of rock burst in the working face.

Abstract: A three-dimensional dynamic and static load test system for simulating deep roadway excavation and a method thereof are provided, which relates to the technical field of indoor simulation testing in underground engineering. The system includes a mobile platform, a box body, a support frame, a roadway excavation device, and a data monitoring unit. The system and method of the disclosure can reproduce the whole process of roadway excavation, simulate the multi-directional loading of deep roadway, and restore the real stress state of deep roadway under the influence of dynamic and static load superimposed disturbance. The problem of insufficient research under the condition of unidirectional static loading and lack of multi-directional dynamic and static loading in current large-scale experimental devices has been solved, and the stress and deformation of the surrounding rock of the roadway are reflected in real-time through the data monitoring unit.

Abstract: The present invention discloses a deformation controllable compression ring-based mechanical test system for rocks with variable stiffness and a test method thereof, which comprises a loading device, a variable stiffness regulating device, a data monitoring system and a controlling system; the energy storing spring in the loading device allows the rebounding direction of the loading device to be contrary to the strain direction of the test-piece, which eliminates the energy supplement of the loading device to the test-piece and realizes the loading of an oversized stiffness on the test system; the variable stiffness regulating device precisely regulates the loaded stiffness by regulating the loaded stiffness of the test system according to test requirements, which realizes the test of loading different stiffness on the same test system and avoids the influences of differences to loading parameters between different test systems on the test results.

Abstract: The disclosure provides a variable dip fault slip simulation test method, which relates to the technical field of indoor simulation test of underground engineering. The variable dip fault slip simulation test method of the disclosure adopts a sample device and a loading device, which includes the following steps: Step 1. sample preparation; Step 2. sample assembly; Step 3. loading preparation; Step 4. sample loading. The variable dip fault slip simulation test method of the disclosure can prepare rock like samples with different dip interfaces, simulate the slip failure process of faults with different dip angles, as well as the normal dip slip and reverse dip slip of faults, facilitate the operation of slip simulation test, and collect test data automatically and accurately.

Abstract: The present invention discloses a deformation controllable compression ring-based mechanical test system for rocks with variable stiffness and a test method thereof, which comprises a loading device, a variable stiffness regulating device, a data monitoring system and a controlling system; the energy storing spring in the loading device allows the rebounding direction of the loading device to be contrary to the strain direction of the test-piece, which eliminates the energy supplement of the loading device to the test-piece and realizes the loading of an oversized stiffness on the test system; the variable stiffness regulating device precisely regulates the loaded stiffness by regulating the loaded stiffness of the test system according to test requirements, which realizes the test of loading different stiffness on the same test system and avoids the influences of differences to loading parameters between different test systems on the test results.

Abstract: The disclosure provides a variable dip fault slip simulation test method, which relates to the technical field of indoor simulation test of underground engineering. The variable dip fault slip simulation test method of the disclosure adopts a sample device and a loading device, which includes the following steps: Step 1. sample preparation; Step 2. sample assembly; Step 3. loading preparation; Step 4. sample loading. The variable dip fault slip simulation test method of the disclosure can prepare rock like samples with different dip interfaces, simulate the slip failure process of faults with different dip angles, as well as the normal dip slip and reverse dip slip of faults, facilitate the operation of slip simulation test, and collect test data automatically and accurately.

Abstract: The present disclosure provides a true triaxial tester with adjustable loading stiffness and a test method, relating to the technical field of rock mechanics. The tester includes a first principal stress variable stiffness loading apparatus, a second principal stress variable stiffness loading apparatus, a third principal stress loading apparatus, a monitoring system, and a control system. The monitoring system includes a stiffness sensor, a pressure sensor, and a displacement sensor. Loading stiffness in a first principal stress direction and a second principal stress direction is adjustable. The tester has the following advantages: it has fixed loading stiffness, can complete stiffness loading of one side being free and five sides being variable, and is easy to operate.

Abstract: The present disclosure provides a true triaxial tester with adjustable loading stiffness and a test method, relating to the technical field of rock mechanics. The tester includes a first principal stress variable stiffness loading apparatus, a second principal stress variable stiffness loading apparatus, a third principal stress loading apparatus, a monitoring system, and a control system. The monitoring system includes a stiffness sensor, a pressure sensor, and a displacement sensor. Loading stiffness in a first principal stress direction and a second principal stress direction is adjustable. The tester has the following advantages: it has fixed loading stiffness, can complete stiffness loading of one side being free and five sides being variable, and is easy to operate.

Abstract: The present disclosure provides an inner and outer framework combined variable stiffness rock mechanics tester and a testing method, relating to the technical field of rock mechanics. The tester includes a stiffness adjusting apparatus, a test loading apparatus, a monitoring system, and a control system. During a test, according to monitoring data, the load of the stiffness adjusting cylinder is controlled through the control system, and the displacement of the inner top beam is adjusted in real time, to ensure that the loading stiffness reaches a design value and remains constant, which solves the technical problem that the loading stiffness of the rock mechanics tester cannot be quantitatively adjusted, and is easy to operate.

Abstract: The present disclosure provides an inner and outer framework combined variable stiffness rock mechanics tester and a testing method, relating to the technical field of rock mechanics. The tester includes a stiffness adjusting apparatus, a test loading apparatus, a monitoring system, and a control system. During a test, according to monitoring data, the load of the stiffness adjusting cylinder is controlled through the control system, and the displacement of the inner top beam is adjusted in real time, to ensure that the loading stiffness reaches a design value and remains constant, which solves the technical problem that the loading stiffness of the rock mechanics tester cannot be quantitatively adjusted, and is easy to operate.

Abstract: An anchor bolt length determination method based on monitoring of a roof rock stratum horizontal extrusion force includes drilling a borehole in the middle of a roadway roof to determine a surrounding rock fracturing scope by a borehole television. The method includes selecting the number and locations of horizontal extrusion force measuring points according to the surrounding rock fracturing scope. The method includes monitoring and recording a change of the horizontal extrusion force over time in the borehole by a device for monitoring a roof rock stratum horizontal extrusion force. The method includes selecting a location with the largest horizontal extrusion force as a center of a anchoring segment of an anchor bolt to determine a distance between the anchoring center and the roof. The method includes calculating a total length of the anchor bolt.

Abstract: The present disclosure provides a stress gradient loading test apparatus and a method of accurately determining loading energy, relating to the technical field of a rock mechanical test. The apparatus includes an upper pressure-bearing plate, a specimen fixing device, a stress transfer device, and a simulation specimen. A computer processes stress and strain monitoring data. The stress transfer device includes a plurality of plate-like high strength materials in combination. A simulation roadway is opened in the simulation specimen, and a strain gauge and a stress sensor are disposed on the simulation specimen. In a test using the apparatus, stress gradient loading is realized and elastic strain energy is calculated by the plate-like high strength materials with different stiffnesses of the stress transfer device, and loading energy acting on the simulation specimen is calculated in combination with energy applied by a tester.