Coal rock mass three-dimensional visual grouting test device and use method

Abstract

The invention discloses a coal and rock mass three-dimensional visual grouting test device and a using method, and belongs to the technical field of broken coal and rock mass grouting reinforcement tests. The device comprises a vertical and horizontal loading system, a three-dimensional filling constraint structure, a visual monitoring system and a regulation and control type grouting system, the vertical and horizontal loading system can apply axial pressure and confining pressure to crushed coal and rock mass, and the underground stress environment is simulated more truly; loading plates are arranged at the left, right and upper parts of the three-dimensional filling constraint structure, high-strength transparent plates are arranged at the front and rear parts of the three-dimensional filling constraint structure, a slurry penetrating plate is arranged at the lower part of the three-dimensional filling constraint structure, and the visual monitoring system realizes real-time observation of the diffusion form and the whole process of slurry in the crushed coal and rock mass through a high-speed camera and a sensor; slurry containing the tracer agent is stably injected into the crushed coal and rock mass through the regulation and control type grouting system. The system is reasonable in structure, convenient to operate, visible in process, stereoscopic in monitoring, safe and reliable.

Description

[0001] This application is a divisional application of a patent application entitled "A three-dimensional visual grouting test device for coal and rock and its use method". The application date of the original application is January 24, 2022, and the application number is 202210078875.8. Technical Field

[0002] The present application relates to a three-dimensional visualized grouting test device for coal and rock mass and a method for using the same, and belongs to the technical field of grouting reinforcement test for broken coal and rock mass. Background Art

[0003] Coal resources are the pillar industry of my country's energy industry. The supply of coal is also related to the stability of the development of my country's energy industry and even the entire society. The safe supply of coal has become the most important part of my country's energy security. With the increasing demand for coal in my country's economic development, the intensity of coal mining has increased, resulting in a decrease in shallow resources and an increase in the mining depth of coal mine tunnels. Mining areas across my country have successively entered the deep mining situation. The serious deterioration of geological conditions in deep rock formations, the increase in broken rock masses, and the large mining stress have aggravated the danger of underground operations, increased the difficulty of coal resource mining, and caused the loose state and fracture of tunnel surrounding rocks to become more and more serious. In the broken coal rock mass, the anchoring force provided by the anchor (cable) support is very poor, and it is impossible to achieve the ideal anchoring effect, which seriously affects the safe and efficient production of coal mine tunnels. Therefore, being able to repair or reasonably control broken or loose coal rock masses has become the technical key to solving deep coal mining projects. After a large number of practical engineering applications and indoor simulation tests, it was found that the grouting technology of injecting slurry into the cracks of broken coal rock at a certain pressure so that the slurry can re-cement the coal rock after solidification has become an effective means of repairing and reinforcing broken rock.

[0004] Grouting technology is a reinforcement technology that uses a certain pressure to inject a fluid-like slurry (cement slurry, chemical slurry, etc.) that can be consolidated into the cracks of the underground rock mass through the grouting hole, and uses the method of replacement filling to repair the rock mass cracks. This technology allows the slurry to replace the cracks that originally existed in the surrounding rock mass after consolidation, and re-cement the rock mass to form a relatively stable and complete body that can bear loads again. However, due to the concealment of the grouting project and the anisotropy of the rock mass itself, it is difficult to accurately obtain the diffusion process and diffusion effect of the slurry in the cracks inside the rock mass, resulting in the difficulty in judging the effect of rock grouting reinforcement. At present, the research on the diffusion law of slurry in broken rock mass mainly focuses on field tests, theoretical research, numerical simulation and indoor tests. Both theoretical research and numerical simulation require certain simplifications of the actual engineering geological conditions and grouting methods, resulting in a large error between the research results and the actual situation; the in-situ test lacks intuitiveness, making it difficult to directly obtain the flow and diffusion of the slurry in the cracks, and it is impossible to obtain key parameters to study the diffusion law. In contrast, indoor tests can better reduce the error between the test and the site, can more realistically simulate the conditions of the grouting site, and can obtain the relevant parameters of the grouting process. However, the existing slurry visualization indoor simulation device only simulates the environment of unidirectional axial pressure, and cannot simulate the situation of surrounding rock mass under confining pressure in deep underground tunnels. It lacks authenticity, and the simulated results have a large error with the real environment. Moreover, the existing visualization equipment only observes the diffusion of the surface of the broken rock mass through a high-speed camera, and cannot obtain the internal slurry flow state.

[0005] Therefore, it is urgent to develop a visualization test device and method that can simulate the conditions of simultaneous axial pressure and confining pressure, and can simultaneously observe the diffusion process of slurry in the crushed coal rock medium both externally and internally, so as to provide an experimental basis for exploring the diffusion law of slurry in the crushed coal rock. Summary of the invention

[0006] In order to solve the shortcomings of the existing technology, a three-dimensional visual grouting test device and a method for using the device are provided for broken loose media such as broken coal and rock, which have a reasonable structure, convenient operation, visible process, three-dimensional monitoring, and are safe and reliable.

[0007] In order to achieve the above objectives, the coal-rock mass three-dimensional visual grouting test device of the present application includes a vertical and horizontal loading system, a three-dimensional loading constraint structure, a visual monitoring system and a control-type grouting system; wherein, a broken coal-rock mass is arranged in the three-dimensional loading constraint structure, the three-dimensional loading constraint structure is arranged to load in the vertical and horizontal loading system, the visual monitoring system is arranged on the side of the three-dimensional loading constraint structure to observe the changes during the loading process, and the control-type grouting system grouts the broken coal-rock mass in the visual monitoring system through a pipeline;

[0008] The vertical and horizontal loading system includes: a steel outer frame of a rectangular frame structure with four sides, each of the four sides of the steel outer frame is vertically provided with a hydraulic cylinder toward the center, and a steel pressure head is provided on the hydraulic cylinder, and the size of the steel pressure head matches the three-dimensional loading constraint structure; the four steel pressure heads can be linked at the same time and loaded at the same rate, or individual steel pressure heads can be controlled separately for loading;

[0009] The three-dimensional loading restraint structure comprises: a hollow cube frame, a slurry-permeable plate integrated with the structure is provided at the bottom of the hollow cube frame, a plurality of holes are opened on the slurry-permeable plate, loading plates with leak-proof step structures are fixed on the left and right sides and the top of the hollow cube frame through rotatable buckles, a high-strength rubber film sealed by a sealing strip is provided between the inner side of the loading plate and the broken coal rock mass, the high-strength rubber film and the sealing strip jointly prevent the slurry from leaking out to achieve double-layer leak-proofing, and high-strength transparent plates made of special armored polycarbonate are respectively provided on the front and rear surfaces of the hollow cube frame through sealing strips; an exhaust hole for exhaust is provided on the top of the hollow cube frame, an exhaust pipe is provided on the exhaust hole, and an exhaust valve is provided on the exhaust pipe;

[0010] The controllable grouting system includes a base on which a high-pressure resistant grouting pipe can be placed, a three-dimensional loading constraint structure is arranged on the base, a plurality of interconnected grouting delivery holes are vertically arranged on the base as required, a plurality of stainless steel grouting pipes are arranged on the interconnected grouting delivery holes as required, the stainless steel grouting pipes are inserted into the broken coal rock mass, and a plurality of composite sensor groups are arranged in the broken coal rock mass in the gaps between the plurality of stainless steel grouting pipes, and the plurality of composite sensor groups are used to observe the diffusion morphology of the slurry in the broken coal rock mass inside the three-dimensional loading constraint structure;

[0011] The composite sensor group includes a permeability pressure sensor, a flow rate sensor, and a pressure sensor. The permeability pressure sensor, the flow rate sensor, and the pressure sensor are arranged in parallel with the stainless steel grouting pipe, and 3 to 5 groups are arranged between the stainless steel grouting pipes. When buried in the broken coal rock mass, the permeability pressure sensor is buried at the lowest position of the three sensors to monitor the permeability pressure of the slurry on the coal rock mass; the pressure sensor is buried at the highest position of the three sensors to measure the extrusion force between the coal rock mass; the flow rate sensor is arranged in the middle position of the three sensors to monitor the flow rate of the slurry in real time;

[0012] A concrete pedestal is provided under the steel outer frame, and the steel outer frame is fixedly connected to the concrete pedestal through multiple high-strength bolts arranged vertically and multiple steel bars arranged horizontally. The hydraulic cylinder is connected to the oil pressure controller through the oil inlet and return pipes. The concrete pedestal provides reaction force when the entire vertical and horizontal loading system is pressurized.

[0013] Furthermore, a slot for fixing the three-dimensional loading constraint structure is provided at the edge of the upper surface of the base, a sealing strip is provided between the slot and the three-dimensional loading constraint structure, a base grouting hole connected to all grouting delivery holes in the fixed three-dimensional loading constraint structure is provided on the base, a flange connected to the base grouting hole is provided under the base, the flange is sequentially connected to a controllable high-pressure pneumatic grouting pump and an electric cement mixing station through a high-pressure resistant grouting pipe, and a multi-channel dynamic grouting monitoring system is provided on the high-pressure resistant grouting pipe.

[0014] Furthermore, the grouting delivery holes are distributed in a 5×5 pattern, the stainless steel grouting pipes are flower pipes, and there are a total of stainless steel grouting pipes, which are arranged on the base at equal intervals.

[0015] Furthermore, the slurry stirred by the electric cement mixing station and injected into the crushed coal rock mass through the high-pressure grouting pipe is a slurry containing a non-radioactive tracer, such as alizarin red or carmine, and the content is 1-5% of the total mass of the slurry.

[0016] Furthermore, the permeability pressure sensor, flow rate sensor and pressure sensor are connected to the data acquisition device and the data processing device in sequence through data cables, and a protective casing is provided on the outside of the data cable part placed in the broken coal rock body; wire holes are provided on the top of the hollow cube frame to allow the data cable of the composite sensor group to pass through.

[0017] Furthermore, the visual monitoring system includes a high-speed camera arranged at the same level as the front of the three-dimensional loading restraint structure, and the high-speed camera is connected to the data processing device via a data cable.

[0018] A method for using a coal-rock mass three-dimensional visualized grouting test device comprises the following steps:

[0019] Step 1: Lay sealing strips around the base, install the hollow cube frame on the card slot of the base, and place the structure connected to the base on the steel pressure head below the vertical and horizontal loading system, place high-strength transparent plates at the front and rear ends of the hollow cube frame, and place sealing strips at the embedded grooves, install high-strength rubber films and loading plates on the left and right sides, and screw the buckles on the left and right sides to prevent the loading plates from being squeezed out when filling the broken coal and rock mass, install the stainless steel grouting pipe on the bottom grouting plate, and then put the broken coal and rock mass sample into the three-dimensional filling constraint structure with the parts installed around it, where the broken coal and rock mass can be either fragmented filling or a block with relatively developed cracks. In this process, the sensor group is wired and sleeved, and the sensor with completed wiring and sleeves is buried in the broken coal and rock mass through the wire hole, and the data received by the sensor is transmitted to the data processor by using the data collector, and finally the high-strength rubber film and loading plate are installed on the upper part of the three-dimensional filling constraint structure, and the sealing strip is placed at the embedded groove in the loading plate;

[0020] Step 2: Control the steel pressure heads on both sides of the vertical and horizontal loading systems to move, and stop when approaching the loading plate, open the buckles on the left and right loading plates, and apply pressure to the installed three-dimensional loading constraint structure in four directions through the vertical and horizontal loading systems, so that the pressure applied by the four steel pressure heads to the broken coal and rock mass reaches a predetermined value. During the process of applying pressure, open the exhaust valve to discharge the gas in the broken coal and rock mass sample through the exhaust pipe;

[0021] Step 3: Connect the electric cement mixing station, the controllable high-pressure pneumatic grouting pump, the multi-channel dynamic grouting monitoring system, and the high-pressure grouting pipe to the grouting hole of the base through the flange plate, put cement, water and an appropriate amount of non-radioactive tracer into the electric cement mixing station in a certain proportion and mix them evenly, and evenly inject the slurry containing non-radioactive tracers such as alizarin red or carmine into the broken coal rock mass through the controllable grouting system, and adjust the grouting pressure as needed;

[0022] The multi-channel dynamic grouting monitoring system is used to monitor the flow rate, density and grouting pressure of the slurry in real time. The sensor group is used to monitor the flow rate, penetration pressure and extrusion pressure of the slurry on the broken coal rock mass. A high-speed camera is used to observe the diffusion morphology and the whole process of the slurry containing non-radioactive tracers such as alizarin red or carmine in the broken coal rock mass in real time.

[0023] Beneficial effects: This device can simulate and reproduce the flow process and diffusion law of slurry when the broken coal rock mass is subjected to axial pressure (simulating vertical geostress in the stratum) and confining pressure (simulating horizontal geostress in the stratum and mutual extrusion and constraint between broken coal rock blocks); this device can not only observe the whole process of slurry flow and diffusion from the outside in real time through a high-speed camera, but also can monitor the flow rate, pressure and extrusion force between coal rock masses when the slurry diffuses inside the broken coal rock mass through sensors such as monitoring slurry flow rate, seepage pressure and extrusion force between coal rock masses buried in the broken coal rock mass. ; The device is designed to prevent leakage to ensure the continuous progress of the test. A sealing strip is provided at each gap of the test device to ensure that there will be no leakage during the grouting process, greatly reducing the impact of leakage on the slurry diffusion; at the same time, the device can also be used to simulate the grouting diffusion law of loose media such as soil, sand, soil-rock mixture under low-pressure compaction and high-pressure splitting grouting conditions, analyze the grouting reinforcement effect and observe the diffusion form and flow process of the slurry during the grouting process in real time; the test device has a reasonable structure, easy operation, visible process, three-dimensional monitoring, safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the overall structure of the coal rock mass three-dimensional visual grouting test device of this application;

[0025] Figure 2This is a schematic diagram of the structure of the vertical and horizontal loading systems in the three-dimensional visual grouting test device for coal and rock mass in this application;

[0026] Figure 3 This is a disassembled diagram of the three-dimensional filling constraint structure in the coal-rock three-dimensional visualization grouting test device of this application;

[0027] Figure 4 This is a schematic diagram of the structure of the visual monitoring system of this application;

[0028] Figure 5 A schematic diagram of a controllable grouting system for this application;

[0029] Figure 6 This is a schematic diagram of the connection between the three-dimensional filling restraint structure and the grouting system of the present application;

[0030] Figure 7 This is a detailed schematic diagram of the sensor wiring in this application;

[0031] In the figure: 1- steel outer frame, 2- hydraulic cylinder, 3- steel pressure head, 4- concrete cap, 5- steel bar, 6- high-strength bolt, 7- oil inlet and return pipeline, 8- oil pressure controller, 9- hollow cube frame, 10- slurry permeable plate, 11- buckle, 12- wire hole, 13- exhaust hole, 14- exhaust pipe, 15- exhaust valve, 16- loading plate, 17- high-strength transparent plate, 18- sealing strip, 19- high-strength rubber film, 20- high-speed camera, 21- penetration pressure Sensor, 22-flow rate sensor, 23-pressure sensor, 24-data acquisition device, 25-data processing instrument, 26-data cable, 27-casing, 28-electric cement mixing station, 29-controllable high-pressure pneumatic grouting pump, 30-multi-channel dynamic grouting monitoring system, 31-high-pressure grouting pipe, 32-base, 33-flange, 34-grouting delivery hole, 35-base grouting hole, 36-stainless steel grouting pipe, 37-non-radioactive tracer, 38-broken coal rock. DETAILED DESCRIPTION

[0032] The present application is further described below in conjunction with the accompanying drawings.

[0033] like Figure 1 As shown, the coal rock three-dimensional visual grouting test device of the present application includes vertical and horizontal loading systems, a three-dimensional loading constraint structure, a visual monitoring system and a control-type grouting system; wherein a broken coal rock 38 is arranged in the three-dimensional loading constraint structure, the three-dimensional loading constraint structure is arranged to load in the vertical and horizontal loading systems, the visual monitoring system is arranged on the side of the three-dimensional loading constraint structure to observe the changes during the loading process, and the control-type grouting system grouts the broken coal rock 38 in the visual monitoring system through a pipeline.

[0034] like Figure 2As shown, the vertical and horizontal loading system includes a steel outer frame 1 of a rectangular frame structure with four sides. A hydraulic cylinder 2 is vertically arranged at the center of each of the four sides of the steel outer frame 1. A steel pressure head 3 is arranged on the hydraulic cylinder 2. The size of the steel pressure head 3 matches the three-dimensional loading constraint structure, which makes the steel pressure head contact with the loading plate over a large area and minimizes the pressure, thereby ensuring that the loading plate has a greater pressure-bearing capacity (uniform force and no local deformation of the loading plate); the four steel pressure heads 3 can be linked simultaneously to load at the same rate, or individual steel pressure heads 3 can be controlled individually to load; the steel pressure heads are precisely controlled by the hydraulic cylinders, so that the system can apply force in multiple directions such as up, down, left and right, and the model To simulate the multi-directional stress state that coal rock mass is subjected to in the actual environment, a vertical and horizontal loading system is set up to load coal rock mass and other materials in multiple directions, including vertical geostress in the stratum, horizontal geostress in the stratum and mutual compression constraint between broken coal rock blocks (i.e. vertical and horizontal directions), so as to simulate the complex stress state that coal rock mass is subjected to in the real environment; four steel pressure heads can be linked simultaneously to load at the same rate to simulate a uniform stress state, or individual steel pressure heads can be controlled separately to load, and different forces are applied in different directions to simulate non-uniform or non-synchronous stress conditions, so as to more comprehensively understand the mechanical response of coal rock mass and improve the accuracy and reliability of the grouting test device. In addition, by using the vertical and horizontal loading system, the present application can simulate both the environment of axial pressure and the situation of confining pressure in the surrounding rock mass of deep underground tunnels, with a high degree of simulation.

[0035] A concrete pedestal 4 is provided under the steel outer frame 1. The steel outer frame 1 is fixedly connected to the concrete pedestal 4 through a plurality of vertically arranged high-strength bolts 6 and a plurality of horizontally arranged steel bars 5. The hydraulic cylinder 2 is connected to an oil pressure controller 8 through an oil inlet and return pipe 7. The concrete pedestal 4 can provide a reaction force when the entire vertical and horizontal loading system is pressurized, and the concrete pedestal 4 has high stability.

[0036] like Figure 3As shown, the three-dimensional loading constraint structure includes a hollow cube frame 9, the lower part of the hollow cube frame 9 is provided with a slurry-permeable plate 10 integrated with the structure, and a plurality of holes are opened on the slurry-permeable plate 10. The left and right sides and the top of the hollow cube frame 9 are fixed with a loading plate 16 with a leak-proof step structure through a rotatable buckle 11. A high-strength rubber film 19 sealed by a sealing strip 18 is provided between the inner side of the loading plate 16 and the broken coal rock mass 38. The high-strength rubber film 19 and the sealing strip 18 jointly prevent the slurry from leaking out to achieve double-layer leak-proofing. The front and rear surfaces of the hollow cube frame 9 are respectively provided with high-strength permeable plates made of special armored polycarbonate through the sealing strip 18. An open plate 17; an exhaust hole 13 for exhaust is provided on the upper part of the hollow cube frame 9, an exhaust pipe 14 is provided on the exhaust hole 13, and an exhaust valve 15 is provided on the exhaust pipe 14; the controllable grouting system includes a base 32 on which a high-pressure grouting pipe can be placed, a three-dimensional loading constraint structure is arranged on the base 32, a plurality of interconnected grouting delivery holes 34 are vertically arranged on the base 32 as needed, a plurality of stainless steel grouting pipes 36 are arranged on the interconnected grouting delivery holes 34 as needed, the stainless steel grouting pipes 36 are inserted into the broken coal rock mass 38, and a plurality of composite sensor groups are arranged in the broken coal rock mass 38 in the gaps between the plurality of stainless steel grouting pipes 36.

[0037] like Figure 4 As shown, the visual monitoring system includes a high-speed camera 20 arranged at the same level as the front of the three-dimensional loading restraint structure. The high-speed camera 20 is connected to a data processor 25 via a data line 26.

[0038] like Figure 5 As shown, a slot for fixing a three-dimensional loading constraint structure is provided at the edge of the upper surface of the base 32, and a sealing strip 18 is provided between the slot and the three-dimensional loading constraint structure. A base grouting hole 35 connected to all grouting delivery holes 34 in the fixed three-dimensional loading constraint structure is provided on the base 32, and a flange 33 connected to the base grouting hole 35 is provided below the base 32. The flange 33 is sequentially connected to a controllable high-pressure pneumatic grouting pump 29 and an electric cement mixing station 28 through a high-pressure grouting pipe 31, and a multi-channel dynamic grouting monitoring system 30 is provided on the high-pressure grouting pipe 31. The grouting delivery holes 34 are distributed in a 5×5 manner, and the stainless steel grouting pipe 36 is a flower pipe. There are 4 stainless steel grouting pipes 36, which are arranged at equal intervals on the base 32. The slurry stirred by the electric cement mixing station 28 and injected into the crushed coal rock mass 38 through the high-pressure grouting pipe 31 is a slurry containing a non-radioactive tracer 37, such as alizarin red or carmine, and the content is 1-5% of the total mass of the slurry.

[0039] like Figure 6 , Figure 7As shown, the composite sensor group includes a permeable pressure sensor 21, a flow rate sensor 22, and a pressure sensor 23. The permeable pressure sensor 21, the flow rate sensor 22, and the pressure sensor 23 are sequentially connected to a data acquisition device 24 and a data processing device 25 via a data line 26, respectively. A protective casing 27 is provided on the outer side of the data line 26 part placed in the broken coal rock mass 38. The permeable pressure sensor 21, the flow rate sensor 22, and the pressure sensor 23 are arranged in parallel with the stainless steel grouting pipe 36, and 3 to 5 groups are arranged between the stainless steel grouting pipes 36. When buried in the broken coal rock mass 38, the permeable pressure sensor 21 is buried at the lowest position of the three sensors, the pressure sensor 23 is buried at the highest position of the three sensors, and the flow rate sensor 22 is located in the middle position of the three sensors, which can capture the three-dimensional installation. The dynamic changes of the diffusion process of the slurry inside the constraint structure are filled; the penetration pressure sensor is buried at the lowest position of the three sensors to monitor the penetration pressure of the slurry on the coal rock mass, so as to capture the initial pressure of the slurry penetration and reflect the degree of diffusion of the slurry in the broken coal rock mass; the pressure sensor is buried at the highest position of the three sensors to measure the extrusion force between the coal rock mass and reflect the stability of the coal rock mass; the flow rate sensor is arranged in the middle position of the three sensors to monitor the flow rate of the slurry in real time and help understand the flow state of the slurry; the flow rate, pressure and extrusion force between the coal rock mass when the slurry diffuses inside the broken coal rock mass are monitored in real time, so as to understand the flow state of the slurry in the broken coal rock mass in real time; the wire holes 12 for allowing the data line 26 of the composite sensor group to pass through are respectively provided above the frame of the hollow cube frame 9.

[0040] Embodiment 1:

[0041] The base 32, the hollow cube frame 9, the loading plate 16 and the steel pressing head 3 are all made of high-strength steel (material specification is Q355-460). The size (length × width) of the base 32 is 300-400mm × 300-400mm, and the thickness is 50-60mm; the size (length × width × thickness) of the hollow cube frame 9 is 300-500mm × 300-500mm × 300-500mm; the high-strength transparent plate is made of special armored polycarbonate, and its size (length × width) is 250-300mm × 250-300mm, and the thickness is 10-20mm; the strength grade of the high-strength bolt is 8.8-10.9, and the bolt hole diameter is 20-26mm; the thickness of the notch of the base 32 is 8-10mm, and the depth is 10-20mm; the diameter of the grouting hole of the base 32 is 10-20mm; the grouting plate 10 is integrated with the three-dimensional filling constraint structure, and its length × width × thickness is 2500- 300mm×2500~300mm×30mm, the diameter of the slurry hole is 10~20mm, the longitudinal and transverse spacing are both 20~30mm, and it is arranged in a 5×5 manner on the slurry permeable plate 10. The grouting pipe is made of stainless steel, and its outer diameter is 20~30mm, which is consistent with the slurry holes on the slurry permeable plate 10. There are slurry holes arranged in a plum blossom shape on the grouting pipe, and the length of the grouting pipe is 100~125mm; the size of the steel pressure head 3 (length×width) is 220~250mm×220~250mm, and the thickness is 20~40mm. The size of the loading plate 16 (length×width) is 220~250mm×220~250mm, and the thickness is 20~30mm. It is provided with an embedded groove with a thickness of 2.0~2.5mm and a width of 8~10mm, and the size of the embedded groove is consistent with the sealing strip. The exhaust pipe is made of seamless steel pipe with a diameter of 8-10mm, a wall thickness of 2-3mm and a length of 50-65mm; the high-pressure grouting pipe has a diameter of 20-30mm and a wall thickness of 3-6mm. The above parameters can be adjusted appropriately according to the actual project conditions.

[0042] A coal-rock mass three-dimensional visualized grouting test device and a method of using the above test device are provided, and the test method comprises the following steps:

[0043] Step 1: If Figure 6 As shown, a sealing strip 18 is laid on the base 32, a specially made hollow cube frame 9 is installed on the card slot of the base 32, and the structure connected with the base 32 is placed as shown in FIG. Figure 2 The vertical and horizontal loading system shown below is on the steel pressure head 3, as shown in FIG. Figure 3 As shown, high-strength transparent plates 17 are placed at the front and rear ends of the specially made hollow cube frame 9, and sealing strips 18 are placed at the embedded grooves. High-strength rubber films 19 and loading plates 16 are installed on the left and right sides, and the buckles 11 on the left and right sides are screwed closed to prevent the loading plates from being squeezed out when the crushed coal rock mass 38 is loaded. Figure 6 As shown, a stainless steel grouting pipe 36 is installed on the bottom grouting plate 10, and then the broken coal rock mass 38 sample is placed in a three-dimensional loading constraint structure with surrounding parts installed. In this process, a variety of sensors are placed as shown in FIG. Figure 7 Wire the cables as shown below. Figure 5 The casing 27 of the data line 26 is sheathed in the manner shown, and 3 to 5 groups of sensors with completed wiring sheathing are buried in the broken coal rock mass 38 through the wire hole 12, and the data received by the sensor is transmitted to the data processor 25 by the data collector 24. Finally, a high-strength rubber film 19 and a loading plate 16 are installed on the upper part of the three-dimensional loading constraint structure, and a sealing strip 18 is placed at the embedded groove of the loading plate 16;

[0044] Step 2: If Figure 1 As shown, the steel pressure heads 3 on both sides of the vertical and horizontal loading systems are controlled to move and stop when approaching the loading plate 16, the buckles 11 on the left and right loading plates 16 are opened, and pressure is applied to the installed three-dimensional loading constraint structure in four directions through the vertical and horizontal loading systems, so that the pressure applied by the four steel pressure heads 3 to the crushed coal and rock mass 38 reaches a predetermined value. In the process of applying pressure, the exhaust valve 15 is opened to discharge the gas in the crushed coal and rock mass 38 sample through the exhaust pipe 14;

[0045] Step 3: If Figure 5 As shown, an electric cement mixing station 28, a controllable high-pressure pneumatic grouting pump 29, a multi-channel dynamic grouting monitoring system 30, and a high-pressure resistant grouting pipe 31 are connected to the grouting hole 35 of the base through a flange 33, and cement, water and an appropriate amount of non-radioactive tracer 37 are put into the electric cement mixing station 28 according to a certain proportion for stirring. After stirring, the slurry uniformly containing non-radioactive tracers 37 such as alizarin red or carmine is uniformly grouted into the broken coal rock mass 38 through the controllable grouting system. The grouting pressure can be adjusted to three levels of low, medium and high pressure, wherein the low pressure is 1-2 MPa, the medium pressure is 3-5 MPa, and the high pressure is 8-10 MPa. When the slurry appears in the exhaust pipe 14, the grouting is stopped;

[0046] The multi-channel dynamic grouting monitoring system 30 is used to monitor the flow rate, density and grouting pressure of the slurry in real time. The internally buried sensors are used to monitor the flow rate, penetration pressure and squeezing force of the slurry on the coal rock mass in real time. A high-speed camera 20 is used to observe the diffusion morphology and the whole process of the slurry containing non-radioactive tracers 37 such as alizarin red or carmine in the high-strength transparent plate 17 in real time in the broken coal rock mass 38.

[0047] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A three-dimensional visual grouting test device for coal and rock mass, characterized in that: The three-dimensional visual grouting test device for coal and rock mass comprises a vertical and horizontal loading system, a three-dimensional loading constraint structure, a visual monitoring system and a control-type grouting system; wherein a broken coal and rock mass (38) is arranged in the three-dimensional loading constraint structure, the three-dimensional loading constraint structure is arranged to load in the vertical and horizontal loading system, the visual monitoring system is arranged on the side of the three-dimensional loading constraint structure to observe changes during the loading process, and the control-type grouting system grouts the broken coal and rock mass (38) in the visual monitoring system through a pipeline; The vertical and horizontal loading system comprises: a steel outer frame (1) of a rectangular frame structure having four sides, a hydraulic cylinder (2) is vertically arranged at the center of each of the four sides of the steel outer frame (1), a steel pressing head (3) is arranged on the hydraulic cylinder (2), and the size of the steel pressing head (3) matches the three-dimensional loading constraint structure; the four steel pressing heads (3) can be linked simultaneously to load at the same rate, or individual steel pressing heads (3) can be controlled individually to load; The three-dimensional loading restraint structure comprises: a hollow cubic frame (9), a slurry permeable plate (10) integrated with the structure is provided at the bottom of the hollow cubic frame (9), a plurality of holes are provided on the slurry permeable plate (10), a loading plate (16) with a leak-proof step structure is fixed on the left and right sides and the top of the hollow cubic frame (9) through a rotatable buckle (11), and a high-strength rubber seal is provided between the inner side of the loading plate (16) and the crushed coal rock mass (38) through a sealing strip (18) The film (19) is a high-strength rubber film (19) and a sealing strip (18) that prevent the slurry from leaking out to achieve double-layer leakage prevention. The front and rear surfaces of the hollow cube frame (9) are respectively provided with high-strength transparent plates (17) made of special armored polycarbonate through the sealing strip (18); an exhaust hole (13) for exhaust is provided above the hollow cube frame (9), an exhaust pipe (14) is provided on the exhaust hole (13), and an exhaust valve (15) is provided on the exhaust pipe (14); The controllable grouting system comprises a base (32) on which a high-pressure resistant grouting pipe can be placed, a three-dimensional loading constraint structure is arranged on the base (32), a plurality of mutually connected grouting delivery holes (34) are vertically arranged on the base (32) as required, a plurality of stainless steel grouting pipes (36) are arranged on the mutually connected grouting delivery holes (34) as required, the stainless steel grouting pipes (36) are inserted into the broken coal rock mass (38), and a plurality of composite sensor groups are arranged in the broken coal rock mass (38) in the gaps between the plurality of stainless steel grouting pipes (36), the plurality of composite sensor groups being used to observe the diffusion morphology of slurry in the broken coal rock mass inside the three-dimensional loading constraint structure; The composite sensor group comprises a permeability pressure sensor (21), a flow rate sensor (22), and a pressure sensor (23). The permeability pressure sensor (21), the flow rate sensor (22), and the pressure sensor (23) are arranged in parallel with the stainless steel grouting pipe (36), and 3 to 5 groups are arranged between the stainless steel grouting pipes (36). When buried in the broken coal rock mass (38), the permeability pressure sensor (21) is buried at the lowest position of the three sensors to monitor the permeability pressure of the slurry on the coal rock mass; the pressure sensor (23) is buried at the highest position of the three sensors to measure the extrusion pressure between the coal rock mass; and the flow rate sensor (22) is arranged in the middle position of the three sensors to monitor the flow rate of the slurry in real time. A concrete pedestal (4) is provided below the steel outer frame (1). The steel outer frame (1) is fixedly connected to the concrete pedestal (4) through a plurality of high-strength bolts (6) arranged vertically and a plurality of steel bars (5) arranged horizontally. The hydraulic cylinder (2) is connected to an oil pressure controller (8) through an oil inlet and return pipe (7). The concrete pedestal (4) provides a reaction force when the entire vertical and horizontal loading system is pressurized.

2. The three-dimensional visualized grouting test device for coal and rock mass according to claim 1 is characterized in that: A slot for fixing the three-dimensional loading constraint structure is provided at the edge of the upper surface of the base (32); a sealing strip (18) is provided between the slot and the three-dimensional loading constraint structure; a base grouting hole (35) connected to all grouting delivery holes (34) in the fixed three-dimensional loading constraint structure is provided on the base (32); a flange (33) connected to the base grouting hole (35) is provided below the base (32); the flange (33) is sequentially connected to a controllable high-pressure pneumatic grouting pump (29) and an electric cement mixing station (28) via a high-pressure grouting pipe (31); and a multi-channel dynamic grouting monitoring system (30) is provided on the high-pressure grouting pipe (31).

3. The three-dimensional visualized grouting test device for coal and rock mass according to claim 1 is characterized in that: The grouting delivery holes (34) are distributed in a 5×5 pattern, and the stainless steel grouting pipes (36) are flower pipes. There are four stainless steel grouting pipes (36) in total, which are arranged on the base (32) at equal intervals.

4. The three-dimensional visualized grouting test device for coal and rock mass according to claim 2 is characterized in that: The slurry stirred by the electric cement mixing station (28) and injected into the crushed coal rock mass (38) through the high-pressure grouting pipe (31) is a slurry containing a non-radioactive tracer (37), such as alizarin red or carmine, and the content is 1-5% of the total mass of the slurry.

5. The three-dimensional visualized grouting test device for coal and rock mass according to claim 1 is characterized in that: The permeability pressure sensor (21), the flow rate sensor (22), and the pressure sensor (23) are sequentially connected to a data acquisition device (24) and a data processing device (25) via data lines (26), and a protective sleeve (27) is provided on the outside of the data line (26) placed in the broken coal rock mass (38); and wire holes (12) are provided above the frame of the hollow cube frame (9) to allow the data line (26) of the composite sensor group to pass through.

6. The three-dimensional visualized grouting test device for coal and rock mass according to claim 1 is characterized in that: The visual monitoring system comprises a high-speed camera (20) arranged at the same level as the front of the three-dimensional loading restraint structure. The high-speed camera (20) is connected to a data processing device (25) via a data line (26).

7. A method for using the three-dimensional visual grouting test device for coal and rock mass according to any one of the above claims, characterized in that: The steps include: Step 1: Lay sealing strips (18) around the base (32), install the hollow cube frame (9) on the card slot of the base (32), and place the structure connected to the base (32) on the steel pressure head (3) below the vertical and horizontal loading system, install high-strength transparent plates (17) at the front and rear ends of the hollow cube frame (9), and install sealing strips (18) at the embedded grooves, install high-strength rubber films (19) and loading plates (16) on the left and right sides, and screw the buckles (11) on the left and right sides to prevent the loading plates from being squeezed out when filling the crushed coal rock mass (38), and install the stainless steel grouting pipe (36) on the bottom grouting plate (10) Then, the broken coal rock mass (38) sample is placed in a three-dimensional loading and restraining structure with surrounding parts installed, wherein the broken coal rock mass (38) can be either a broken block filling or a block with relatively developed cracks. In this process, the sensor group is wired and sleeved, and the wired and sleeved sensor is buried in the broken coal rock mass (38) through the wire hole (12). The data collected by the sensor is transmitted to the data processor (25) by the data acquisition device (24). Finally, a high-strength rubber film (19) and a loading plate (16) are installed on the upper part of the three-dimensional loading and restraining structure, and a sealing strip (18) is placed in the embedded groove of the loading plate (16); Step 2: Control the steel pressure heads (3) on both sides of the vertical and horizontal loading systems to move and stop when approaching the loading plate (16), open the buckles (11) on the left and right loading plates (16), and apply pressure in four directions to the installed three-dimensional loading constraint structure through the vertical and horizontal loading systems, so that the pressure applied by the four steel pressure heads (3) to the crushed coal and rock mass (38) reaches a predetermined value. During the process of applying pressure, open the exhaust valve (15) to allow the gas in the crushed coal and rock mass (38) sample to be discharged through the exhaust pipe (14); Step 3: The electric cement mixing station (28), the controllable high-pressure pneumatic grouting pump (29), the multi-channel dynamic grouting monitoring system (30), and the high-pressure grouting pipe (31) are connected to the grouting hole (35) of the base through the flange (33), cement, water and an appropriate amount of non-radioactive tracer (37) are put into the electric cement mixing station (28) according to a certain proportion and stirred evenly, and the slurry containing non-radioactive tracers (37) such as alizarin red or carmine after stirring evenly is uniformly grouted into the broken coal rock mass (38) through the controllable grouting system, and the grouting pressure is adjusted according to needs; The flow rate, density and grouting pressure of the slurry are monitored in real time by a multi-channel dynamic grouting monitoring system (30), the flow rate, osmotic pressure and the squeezing force of the slurry on the broken coal rock mass (38) are monitored by a sensor group, and the diffusion form and the whole process of the slurry containing non-radioactive tracers (37) such as alizarin red or carmine in a high-strength transparent plate (17) in the broken coal rock mass (38) are observed in real time by a high-speed camera (20).

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