Device and method for testing seepage stability of unconsolidated formation

Abstract

The invention relates to a device and a method for testing the seepage stability of a unconsolidated formation, and belongs to the technical field related to rock soil, the device for testing the seepage stability of the unconsolidated formation comprises a visual solid-liquid mixing bearing container, an articulated crack channel, a vertical loading device, a volume pressure control device, a displacement stress controller and a main control computer; a real scene is simulated through the device for testing the seepage stability of the unconsolidated formation, experiments of two stages are completed based on the device to obtain experimental data, the seepage stability of the unconsolidated formation is determined according to the experimental data through a structural stability judgment formula, and engineering loss caused by lack of stability judgment can be effectively reduced.

Description

Technical Field

[0001] The invention belongs to the technical field related to rock and soil, and particularly relates to a loose layer seepage stability testing device and a testing method. Background Art

[0002] The main coal seams in the North my country mining area are mainly located in deep strata. The main component of the bedrock aquifer is sandstone aquifer, and the water-richness is relatively weak. The water level and water-richness tend to decrease with the expansion of mining activities and continuous drainage. However, due to the generally high initial water level and high water pressure of the aquifer, it is difficult to completely drain the aquifer water within a certain period of time. During the mining process, the bedrock aquifer still retains a part of the water body and is continuously drained with the expansion of mining activities. Continuous drainage provides dynamic water for the migration of loose sand bodies, resulting in a large amount of sand bodies being transported from the overlying loose layer into the mining face by water, causing water inrush and sand burst accidents, causing serious engineering disasters. Therefore, there is an urgent need for a device and method for testing the stability of deep loose layers after drainage. Summary of the invention

[0003] To this end, the present invention provides a loose layer seepage stability testing device and a testing method to solve the problem that the prior art is unable to test the stability of the deep loose layer after drainage.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a loose layer seepage stability testing device, comprising: Visual solid-liquid mixed carrying container, articulated fracture channel, vertical loading device, volume pressure control device, displacement stress controller and main control computer; The vertical loading device is arranged on the top of the visualized solid-liquid mixing carrying container; the vertical loading device is electrically connected to the displacement stress controller; A pressure valve, a water outlet valve and a plurality of pore water pressure sensors are arranged on the left wall of the visualized solid-liquid mixing container; a water supply pipeline is connected between the pressure valve and the volume pressure control device; the pore water pressure sensor is electrically connected to the volume pressure control device; The lower end of the visualized solid-liquid mixing container is provided with a waterproof groove bottom plate; the upper part of the articulated crack channel is provided in the groove of the waterproof groove bottom plate; a water-sand mixture collection box is provided below the lower part of the articulated crack channel; a drainage pipe is provided at the bottom of the water-sand mixture collection box; the drainage pipe is connected to a water collecting tank; The volume pressure control device and the displacement stress controller are electrically connected to the main control computer respectively.

[0005] Furthermore, the visualized solid-liquid mixed carrying container also includes a cover plate and a container ring wall; the cover plate and the container ring wall are fixedly connected to form a cavity; a sealing rubber ring is provided on the contact surface between the cover plate and the container ring wall; a through hole is provided in the center of the cover plate; a pressure relief ball valve and multiple pressure measuring tubes are provided on the right side of the visualized solid-liquid mixed carrying container; the inner cavity of the visualized solid-liquid mixed carrying container is connected to the groove of the waterproof groove bottom plate.

[0006] Further, the articulated crack channel includes two adjustable channel arms; the adjustable channel arms include at least three water-proof sliding hinge plates, at least two crack channel hinge plates and at least three threaded rods; the two ends of the crack channel hinge plate are respectively hinged to the upper surface or lower surface of one end of two adjacent water-proof sliding hinge plates; the other end of the water-proof sliding hinge plate is fixedly connected to one end of the threaded rod; limit strips are arranged on both sides of the water-proof sliding hinge plate; the limit strips correspond to the limit grooves on the side walls of the groove of the waterproof groove bottom plate; the crack channel hinge plate is provided with a storage groove.

[0007] Furthermore, the vertical loading device includes a loading base, a pressure column, a loading pressure head, a loading cylinder, a loading piston and a pressure sensor; one end of the pressure column passes upward through the through hole in the center of the cover plate, and a sealing device is provided at the contact surface between the cylindrical surface of the pressure column and the through hole; the upper surface of the loading base is fixedly connected to the other end of the pressure column; the loading base is placed at the lower end of the cover plate; the loading pressure head is placed at the upper end of the pressure column; the upper part of the loading piston is sleeved in the loading cylinder; the lower end of the loading piston is fixedly connected to the loading pressure head; the pressure sensor is placed inside the loading cylinder; and the pressure sensor is electrically connected to the displacement stress controller.

[0008] Furthermore, it also includes a supporting steel frame; the upper part of the vertical loading device, the bottom of the water-sand mixture collecting box and the bottom of the waterproof groove bottom plate are respectively fixedly connected to the supporting steel frame.

[0009] Furthermore, it also includes multiple adjustable connecting rods; the adjustable connecting rods include a different-direction articulated tube clamp, a double-hole articulated rod and a single-sided articulated rod; the different-direction articulated tube clamp is fixedly connected to the support column of the supporting steel frame; the articulation hole of the different-direction articulated tube clamp is articulated to one end of the double-hole articulated rod; the other end of the double-hole articulated rod is articulated to one end of the single-sided articulated rod; the other end of the single-sided articulated rod is articulated to the threaded rod.

[0010] Furthermore, the water-sand mixture collection box includes a box body and a filtering device; the filtering device includes a plurality of hanging long arms and a permeable plate; the lower end of the hanging long arm is fixedly connected to the permeable plate; the upper end of the hanging long arm is provided with a hook, and the hook is hung on the top of the ring wall of the box body.

[0011] Furthermore, the bottom of the water-sand mixture collection box and the bottom of the water collecting tank are both provided with precision weighing devices; and at least one high-speed camera is provided around the visual solid-liquid mixing carrying container.

[0012] In a second aspect, the present invention provides a loose layer seepage stability test method, which is applied to any of the loose layer seepage stability test devices described above, and the test method comprises: The sand sample is placed in a visualized solid-liquid mixing carrying container, and a drainage experiment and a deep loose layer seepage experiment are performed on the sand sample based on the loose layer seepage stability testing device to obtain experimental data; According to the experimental data, the seepage stability of the loose layer is determined by the structural stability judgment formula.

[0013] Further, the experimental data at least include the average particle size of the sand sample particles, the bottom area of ​​the visualized solid-liquid mixed carrying container, the total mass of the vertical loading device, the distance between the initial free liquid surface position and the bottom plate of the waterproof groove, the bulk density of water, the friction coefficient of the sand body particles, the water pressure at the free liquid surface position, the water pressure of the waterproof groove bottom plate, the crack width and the diameter of the visualized solid-liquid mixed carrying container; the loose layer seepage stability is determined by the structural stability judgment formula based on the experimental data, including: According to the experimental data, vertical force, friction force, matrix suction, osmotic pressure and water pressure are obtained; determining the sum of stresses based on the vertical force, friction force, matrix suction, osmotic pressure and water pressure; According to the experimental data, the friction force and the sum of the stress, the seepage stability of the loose layer is determined by a structural stability judgment formula; the structural stability judgment formula is: ; Among them, F is the state value, F≥ the loose layer structure is in an unstable state, F< the loose layer structure is in a stable state; is the sum of stresses; D is the crack width; L is the diameter of the visualized solid-liquid mixing container; For friction.

[0014] The present invention adopts the above technical solution and has at least the following beneficial effects: (1) The loose layer seepage stability testing device of the present invention simulates a situation close to reality by controlling various factors inside the visualized solid-liquid mixing container, such as controlling the hydraulic pressure difference to make the internal environment close to the actual water flow situation; setting a vertical loading device to simulate the effect of deep vertical stress on the sand layer; setting an outlet valve to achieve deep formation drainage conditions; and setting an articulated fracture channel to achieve water inrush and sand bursting conditions under different fracture widths, shapes and roughness conditions.

[0015] (2) The loose layer seepage stability testing method of the present invention is based on the loose layer seepage stability testing device, and the experiment is set into two stages. The first stage is a drainage experiment, and the second stage is a deep loose layer seepage experiment. The experimental data of relevant drainage and water-sand inrush are collected through the experiments in the above two stages. According to the experimental data, the loose layer seepage stability is determined by the structural stability judgment formula, which realizes the judgment of the loose layer seepage stability before mining, and can effectively reduce the engineering losses caused by the lack of stability judgment.

[0016] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0018] Figure 1 It is a structural schematic diagram of a loose layer seepage stability testing device shown in an exemplary embodiment of the present invention; Figure 2 yes Figure 1 Enlarged view of part A in the middle; Figure 3 is a schematic structural diagram of a visualized solid-liquid mixing carrying container shown in an exemplary embodiment of the present invention; Figure 4 yes Figure 3 Enlarged view of middle part B; Figure 5 is a schematic structural diagram of an articulated fracture channel shown in an exemplary embodiment of the present invention; Figure 6 yes Figure 5 Enlarged view of the middle C part; Figure 7 is a schematic diagram of the structure after the visual solid-liquid mixed carrying container and the articulated fracture channel are assembled A; Figure 8 is a schematic diagram of the structure after the visual solid-liquid mixed carrying container and the articulated fracture channel are assembled B; Fig. 9 is a structural schematic diagram A of a supporting steel frame shown in an exemplary embodiment of the present invention; Fig.10 is a structural schematic diagram B of a supporting steel frame shown in an exemplary embodiment of the present invention; Fig.11is a schematic structural diagram of an adjustable connecting rod shown in an exemplary embodiment of the present invention; Fig.12 is a schematic structural diagram of a water-sand mixture collecting box shown in an exemplary embodiment of the present invention; Fig.13 is a flow chart of a loose layer seepage stability testing method shown in an exemplary embodiment of the present invention; Reference numerals: 1-visualized solid-liquid mixing carrying container, 2-articulated fracture channel, 3-vertical loading device, 4-volume pressure control device, 5-displacement stress controller, 6-main control computer, 7-water-sand mixture collection box, 8-water collection tank, 9-support steel frame; 101-pressure valve, 102-water outlet valve, 103-pore water pressure sensor, 104-waterproof groove bottom plate, 105-cover plate, 106-container ring wall, 107-pressure relief ball valve, 108-pressure measuring tube, 109-limiting groove; 21-adjustable channel arm, 211-waterproof sliding hinge plate, 212-crack channel hinge plate, 213-threaded rod, 214-limiting strip, 215-storage tank; 3 01-loading base, 302-pressure column, 303-loading pressure head, 304-loading piston, 305-loading cylinder, 306-pressure sensor; 22-adjustable connecting rod, 221-different-direction hinged pipe clamp, 222-double-hole hinged rod, 223-single-side hinged rod, 224-hinge hole; 701-box, 702-filter device, 703-hanging long arm, 704-permeable plate, 705-hook.

[0019] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0021] The main coal seams in the North China mining area are mainly located in deep strata. The main component of the bedrock aquifer is sandstone aquifer, and the water-richness is relatively weak. The water level and water-richness often decrease with the expansion of mining activities and continuous drainage. However, due to the generally high initial water level and high water pressure of the aquifer, it is difficult to completely drain the aquifer water within a certain period of time. During the mining process, the bedrock aquifer still retains a part of the water body and continues to drain with the expansion of mining activities. Continuous drainage provides dynamic water for the migration of loose sand bodies, resulting in a large amount of sand bodies being transported from the overlying loose layer into the mining working face by water, causing water inrush and sand burst accidents, causing serious engineering disasters. Therefore, it is urgent to study the stability of the deep loose layer after drainage.

[0022] The embodiments of the present invention provide a loose layer seepage stability testing device and a testing method. The loose layer seepage stability testing device is used to simulate a real scene, and two stages of experiments are completed based on the device to obtain experimental data. Based on the experimental data, the loose layer seepage stability is determined by a structural stability judgment formula, which can effectively reduce engineering losses caused by lack of stability judgment.

[0023] The method and device of the present invention are described below through specific embodiments.

[0024] See also Figure 1 , Figure 1 is a schematic diagram of a loose layer seepage stability testing device according to an exemplary embodiment of the present invention, see Figure 1 The device comprises: a visualized solid-liquid mixed carrying container 1, an articulated crack channel 2, a vertical loading device 3, a volume pressure control device 4, a displacement stress controller 5 and a main control computer 6; the vertical loading device 3 is arranged on the top of the visualized solid-liquid mixed carrying container 1; the vertical loading device 3 is electrically connected to the displacement stress controller 5; a pressurizing valve 101, a water outlet valve 102 and a plurality of pore water pressure sensors 103 are arranged on the left wall of the visualized solid-liquid mixed carrying container 1; a water supply pipeline is connected between the pressurizing valve 101 and the volume pressure control device 4; the pore water pressure sensor 103 is electrically connected to the volume pressure control device 4; a waterproof groove bottom plate 104 is arranged at the lower end of the visualized solid-liquid mixed carrying container 1; the upper part of the articulated crack channel 2 is arranged in the groove of the waterproof groove bottom plate 104; a water-sand mixture collection box 7 is arranged below the lower part of the articulated crack channel 2; a drainage pipeline is arranged at the bottom of the water-sand mixture collection box 7; the drainage pipeline is connected to a water collecting box 8; the volume pressure control device 4 and the displacement stress controller 5 are electrically connected to the main control computer 6 respectively.

[0025] Specifically, a plurality of pore water pressure sensors 103 are arranged at different heights on the left side wall of the visualized solid-liquid mixing container 1 ; the water collecting box 8 is located lower than the bottom of the water-sand mixture collecting box 7 .

[0026] It can be understood that the device provided in this embodiment simulates a situation close to reality by controlling various factors inside the visualized solid-liquid mixing container, such as controlling the hydraulic pressure difference to make the internal environment close to the actual water flow situation; setting a vertical loading device to simulate the effect of deep vertical stress on the sand layer; setting an outlet valve to achieve deep formation drainage conditions; and setting an articulated fracture channel to achieve water inrush and sand bursting conditions under different fracture widths, shapes and roughness conditions.

[0027] See also Figure 3 , Figure 3 is a schematic diagram of a structure of a visualized solid-liquid mixing container according to an exemplary embodiment of the present invention, see Figure 3 The visualized solid-liquid mixed carrying container 1 also includes a cover plate 105 and a container ring wall 106; the cover plate 105 and the container ring wall 106 are fixedly connected to form a cavity; a sealing rubber ring is provided on the contact surface between the cover plate 105 and the container ring wall 106; a through hole is provided in the center of the cover plate 105; a pressure relief ball valve 107 and a plurality of pressure measuring tubes 108 are provided on the right side of the visualized solid-liquid mixed carrying container 1; the inner cavity of the visualized solid-liquid mixed carrying container 1 is connected to the groove of the waterproof groove bottom plate 104.

[0028] Specifically, the pressure relief ball valve 107 is arranged near the top; a plurality of pressure measuring tubes 108 are arranged in sequence below the pressure relief ball valve 107, and each pressure measuring tube 108 is located at a different height on the side wall.

[0029] See also Figures 4 to 8 , Figure 4 yes Figure 3 Enlarged view of middle part B; Figure 5 is a schematic structural diagram of an articulated fracture channel shown in an exemplary embodiment of the present invention; Figure 6 yes Figure 5 Enlarged view of the middle C part; Figure 7 is a schematic diagram of the structure after the visual solid-liquid mixed carrying container and the articulated fracture channel are assembled A; Figure 8 is a schematic diagram of the structure after the visual solid-liquid mixed carrying container and the articulated fracture channel are assembled. Figures 4 to 8 The articulated crack channel 2 includes two adjustable channel arms 21; the adjustable channel arms 21 include at least three water-proof sliding hinges 211, at least two crack channel hinges 212 and at least three threaded rods 213; the two ends of the crack channel hinge 212 are respectively hinged to the upper surface or lower surface of one end of two adjacent water-proof sliding hinges 211; the other end of the water-proof sliding hinge 211 is fixedly connected to one end of the threaded rod 213; limiting strips 214 are arranged on both sides of the water-proof sliding hinge 211; the limiting strips 214 correspond to the limiting grooves 109 on the side walls of the groove of the waterproof groove bottom plate 104; the crack channel hinge 212 is provided with a storage groove 215.

[0030] Specifically, rock plates and gaskets may be placed in the storage tank 215 to simulate cracks of various roughnesses.

[0031] See also Figure 2 , Figure 2 yes Figure 1 Enlarged view of part A in the middle; see Figure 2 The vertical loading device 3 includes a loading base 301, a pressure column 302, a loading pressure head 303, a loading piston 304, a loading cylinder 305 and a pressure sensor 306; one end of the pressure column 302 passes upward through the through hole in the center of the cover plate 105, and a sealing device is provided on the contact surface between the cylindrical surface of the pressure column 302 and the through hole; the upper surface of the loading base 301 is fixedly connected to the other end of the pressure column 302; the loading base 301 is placed at the lower end of the cover plate 105; the loading pressure head 303 is placed at the upper end of the pressure column 302; the upper part of the loading piston 304 is sleeved in the loading cylinder 305; the lower end of the loading piston 304 is fixedly connected to the loading pressure head 303; the pressure sensor 306 is placed inside the loading cylinder 305; the pressure sensor 306 is electrically connected to the displacement stress controller 5.

[0032] Specifically, the sealing device may be a sealing rubber ring, the upper surface of the loading base 301 and the pressure-bearing column 302 may be welded, and the lower end of the loading piston 305 and the loading pressure head 303 may be welded.

[0033] See also Figure 5 , Fig. 9 , Fig.10 , Fig.11 , Figure 5 is a schematic structural diagram of an articulated fracture channel shown in an exemplary embodiment of the present invention; Fig. 9 is a structural schematic diagram A of a supporting steel frame shown in an exemplary embodiment of the present invention; Fig.10 is a structural schematic diagram B of a supporting steel frame shown in an exemplary embodiment of the present invention; Fig.11 is a schematic structural diagram of an adjustable connecting rod according to an exemplary embodiment of the present invention; Figure 5 , Fig. 9 , Fig.10 , Fig.11 , also includes a supporting steel frame 9; the upper part of the vertical loading device 3, the bottom of the water-sand mixture collecting box 7 and the bottom of the waterproof groove bottom plate 104 are respectively fixedly connected to the supporting steel frame 9; also includes a plurality of adjustable connecting rods 22; the adjustable connecting rod 22 includes a different direction hinged pipe clamp 221, a double-hole hinged rod 222 and a single-side hinged rod 223; the different direction hinged pipe clamp 221 is fixedly connected to the supporting column of the supporting steel frame 9; the hinge hole 224 of the different direction hinged pipe clamp 221 is hinged to one end of the double-hole hinged rod 222; the other end of the double-hole hinged rod 222 is hinged to one end of the single-side hinged rod 223; the other end of the single-side hinged rod 223 is hinged to the threaded rod 213.

[0034] Specifically, the number of adjustable connecting rods 22 is the same as the number of threaded rods 213 in the articulated crack channel 2 .

[0035] See also Fig.12 , Fig.12 is a schematic structural diagram of a water-sand mixture collecting box according to an exemplary embodiment of the present invention; Fig.12 The water-sand mixture collecting box 7 comprises a box body 701 and a filtering device 702; the filtering device 702 comprises a plurality of hanging long arms 703 and a water-permeable plate 704; the lower end of the hanging long arm 703 is fixedly connected to the water-permeable plate 704; the upper end of the hanging long arm 703 is provided with a hook 705, and the hook 705 is hung on the top of the ring wall of the box body 701.

[0036] Specifically, a precision weighing device is disposed at the bottom of the water-sand mixture collecting box 7 and the bottom of the water collecting box 8 ; and at least one high-speed camera is disposed around the visual solid-liquid mixing carrying container 1 .

[0037] In a specific practice of an embodiment, first, a water-sand mixture is placed inside the visualized solid-liquid mixed carrying container 1, and a cover plate 105 is located at the upper part of the visualized solid-liquid mixed carrying container 1 and has bolt holes, which are connected by bolts; a permeable stone plate is provided inside the water outlet valve 102, and a pressure column 302 is a solid steel column, which is welded to a loading base 301; the loading base 301 is located at the upper part of the water-sand mixture, and a supporting steel frame 9 is located at the outer periphery of the visualized solid-liquid mixed carrying container 1, and the steel frames of the supporting steel frame 9 are connected by welding; the loading piston 304 A loading pressure head 303 is welded at one end, and a loading cylinder 305 is loaded at the other end; the loading cylinder 305 is located above the loading piston 304, and the displacement stress controller 5 controls the internal hydraulic pressure of the loading cylinder 305 to control the loading piston 304 to move up and down; the pressure sensor 306 is located inside the loading cylinder, and is connected to the main control computer 6 through a data line together with the displacement stress controller 5; gaskets and prefabricated rock plates are placed in the storage slot 215 of the crack channel hinge plate 212; the water-proof sliding hinge plate 211 and the waterproof groove bottom plate 104 are mortise and tenoned on the same plane The waterproof sliding hinge plate 211 is connected with the crack channel hinge plate 212 by means of a through round rod; the threaded rod 213 is welded to the waterproof sliding hinge plate 211; the adjustable asymmetric hinged pipe clamp 221 is divided into a pipe clamp hole and a hinge hole 224, the pipe clamp hole is fixed by tightening bolts, one end of the double-hole hinged rod 222 is hinged to the hinge hole, and the other end is hinged to the single-side hinged rod 223, and the single-side hinged rod 223 is fixedly connected to the threaded rod 8; the water-sand mixture collection box 7 is located at the lower part of the hinged crack channel 2, and also It includes a ball valve, a permeable plate 704, and a hangable long arm 703; the permeable plate 704 is located inside the water-sand mixture collecting box 7, the flat surface of the hangable long arm 703 is at the lower part of the permeable plate 704, the flat surface is composed of four steel bars, the middle part is fixed with bolts, and the bending part is suspended on the outer wall of the water-sand mixture collecting box 7; the water collecting box 8 is connected to the ball valve of the water-sand mixture collecting box 7 through a drainage pipe, and a precision electronic scale is respectively at the lower part of the water-sand mixture collecting box 7 and the water collecting box 8. A high-speed camera is set up outside the supporting steel frame 9 to record the movement process of water and sand bursting.

[0038] It should be noted that: the visual solid-liquid mixed carrying container 1 is used to carry water-sand two-phase samples, the volume pressure controller 4 adjusts the water supply pressure to change the initial water pressure condition of the sand layer, and the pressure relief ball valve 107 and the pore water pressure sensor 403 are used to monitor the changes in pore water pressure at different depths; the vertical loading device 3 applies vertical pressure by adjusting the loading cylinder 305 hydraulic pressure to push the loading piston 304 to obtain vertical loads at different depths for loose layer stability tests. Permeable stones are placed at the water outlet valve 102 to achieve water-sand separation, and loose layer stability tests can be performed at different precipitation depths by controlling the valve switch. The articulated crack channel 2 is connected to the waterproof groove bottom plate 104 at the bottom of the visualized solid-liquid mixing container 1 by mortise and tenon joints. By moving and rotating the asymmetric articulated pipe clamp 221, the double-hole articulated rod 222 and the single-side articulated rod 223, the movement of the water-isolating sliding hinge plate 211 and the crack channel hinge plate 212 can be controlled to achieve different crack widths and crack shapes; by replacing the rock plate on the crack channel hinge plate 212, cracks of different roughness can be obtained. A water-sand mixture collection box 7 is placed at the bottom of the articulated crack channel 2, and the permeable plate 704 is used to separate the water-sand mixture. The hangable long arm 703 is flat at the bottom of the permeable plate 704 to facilitate the extraction of the permeable stone plate and sand body; after the water-sand surge ends, the ball valve is opened, and the water in the water-sand mixture collection box 7 is discharged into the water collection box 8 through the drainage pipe; the precision electronic scale is at the bottom of the water-sand mixture collection box 7 and the water collection box 8, respectively, for weighing the mass of the water-sand mixture and water, and the high-speed camera is used to observe and record the dynamic changes of the water-bearing sand layer.

[0039] See also Fig.13 , Fig.13 is a flow chart of a loose layer seepage stability test method shown in an exemplary embodiment of the present invention; see Fig.13 The loose layer seepage stability test method includes: Step S11, placing the sand sample in a visualized solid-liquid mixing carrying container, and performing drainage experiments and deep loose layer seepage experiments on the sand sample based on a loose layer seepage stability testing device to obtain experimental data; Step S12: Determine the seepage stability of the loose layer through the structural stability judgment formula based on the experimental data.

[0040] It should be noted that the loose layer seepage stability testing method provided in this embodiment is applied to the loose layer seepage stability testing device provided in any of the above embodiments.

[0041] It can be understood that the loose layer seepage stability test method provided in this embodiment is based on the loose layer seepage stability test device, and the experiment is set as two stages. The first stage is the drainage experiment, and the second stage is the deep loose layer seepage experiment. The experimental data of relevant drainage and water-sand sudden surge are collected through the experiments in the above two stages. According to the experimental data, the loose layer seepage stability is determined by the structural stability judgment formula, which realizes the judgment of the loose layer seepage stability before mining, and can effectively reduce the engineering losses caused by the lack of stability judgment.

[0042] In specific practice, the experimental data at least include the average particle size of sand sample particles, the bottom area of ​​the visualized solid-liquid mixing carrying container, the total mass of the vertical loading device, the distance between the initial free liquid surface position and the bottom plate of the waterproof groove, the specific gravity of water, the friction coefficient of sand particles, the water pressure at the free liquid surface position, the water pressure of the waterproof groove low plate, the crack width and the diameter of the visualized solid-liquid mixing carrying container.

[0043] In specific practice, in step S12, "determining the seepage stability of the loose layer by means of a structural stability discriminant formula based on experimental data" includes: obtaining vertical force, friction force, matrix suction, seepage pressure and water pressure based on experimental data; determining the sum of stresses based on vertical force, friction force, matrix suction, seepage pressure and water pressure; determining the seepage stability of the loose layer by means of a structural stability discriminant formula based on experimental data, the sum of friction force and stress; the structural stability discriminant formula is: ; Among them, F is the state value, F ≥ 0 means the loose layer structure is in an unstable state, and F < 0 means the loose layer structure is in a stable state; is the sum of stresses; D is the crack width; L is the diameter of the visualized solid-liquid mixing container; For friction.

[0044] Specifically, the drainage test includes: S21, recording the mass of the sand sample, placing the sand sample in a visual solid-liquid mixed bearing container, and placing the loading pressure head, loading cylinder, and loading piston on the upper part of the cover plate, placing the pressure column and the loading base on the surface of the sand sample, fixing the cover plate with bolts, and applying a sealing ring to the gap between the cover plate and the pressure column; turning on the displacement stress controller, controlling the hydraulic pressure in the loading cylinder to propel the loading piston to move so that the loading pressure head is in horizontal contact with the pressure column, setting the required loading pressure, and recording the loading pressure at this time; S22, opening the pressurizing valve and the volume pressure control device, allowing water with a certain pressure to flow into the visualized solid-liquid mixing container through the water supply channel, and recording the water pressure difference between the free liquid surface position and the articulated fracture channel position; S23. Close the pressurizing valve and volume pressure control device, open the water outlet valve, and record the water pressure difference between the free liquid surface position and the waterproof groove floor position, as well as the drainage quality.

[0045] Specifically, the deep loose layer seepage test includes: S24, weigh and record the water-sand mixture collection box and the water collection tank respectively using a precision electronic scale, and close the ball valve; S25. Install the rock plate and gasket on the hinge plate of the crack channel and install the speed sensor; move each layer of the water-blocking sliding hinge plate respectively, record the moving scale and the rotation angle, pass the extended threaded rod of the water-blocking sliding hinge plate through the single-side hinge rod, and fix it with a nut; place a high-definition camera to record the time from the movement of the water-blocking sliding hinge plate to the beginning of the water and sand bursting, the beginning time of the sand bursting, the end time of the sand bursting, the movement state of the water and sand in the visual solid-liquid mixing container, and the water pressure difference between the free liquid surface position and the drainage device position at the end of the water and sand bursting; S26. Record the data of the precision electronic scale after the sudden surge of water and sand. Open the ball valve when the water and sand are separated in the water-sand mixture collection box. When the water in the water-sand mixture collection box completely flows into the water collecting tank, record the data of the precision electronic scale at this time.

[0046] Specifically, in step S25, the crack channel opening is derived, wherein the left movement distance of the first layer of water-blocking sliding hinge plate is , the left side movement distance of the second layer is , the left side movement distance of the third layer is , the right side movement distance of the first layer is , the right moving distance of the second layer is , the right moving distance of the third layer is The crack width is , the minimum crack opening is , where C is the length of the long side of the hinge plate of the crack channel, , , , They are the angles measured by the hinge plates of each crack channel.

[0047] Specifically, the water mass calculation formula in the visualized solid-liquid mixing container after drainage is: .

[0048] The formula for calculating the mass of the water-sand mixture in the water-sand mixture collection box is: .

[0049] Sand mass calculation formula .

[0050] Visualize the remaining water mass in a solid-liquid mixing container .

[0051] Residual sand quality .

[0052] The calculation formula for the mass flow rate of water-sand movement is: , water-sand average mass flow calculation formula .

[0053] The initial water volume is m w0 , drainage quality m w1 , initial mass of sand body m s0 , initial water-sand mixture collection box mass m 1 , the mass of the water-sand mixture collection box after the sand is broken is m 2 , water mass of water collecting tank m w3 , t 1 t is the time from sand burst to the end of sand burst, 2 The opening time of the water-proof sliding hinge plate lasts until the sand burst ends.

[0054] Specifically, when determining the seepage stability of loose layers, The calculation formula of vertical force is: .

[0055] The formula for calculating friction is: .

[0056] The calculation formula of matrix suction is: .

[0057] The formula for calculating osmotic pressure is: .

[0058] The water pressure calculation formula is: .

[0059] The formula for calculating the sum of stresses is .

[0060] The structural stability judgment formula is: , where F is the state value, F ≥ 0 means the loose layer structure is in an unstable state, F < 0 means the loose layer structure is in a stable state, d is the average particle size of the sand particles, A is the bottom area of ​​the visualized solid-liquid mixing container, is the total mass of the vertical loading device, is the distance between the initial free liquid surface position and the waterproof groove floor, is the specific gravity of water, is the friction coefficient of sand particles, P2 is the water pressure at the free liquid surface, P1 is the water pressure of the waterproof groove floor, and L is the diameter of the visualized solid-liquid mixing container.

[0061] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0063] It should also be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for display, data for analysis, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0064] Each embodiment in this specification is described in a related manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0065] The technical features of the above embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0066] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. A loose layer seepage stability testing device, characterized in that: include: A visualized solid-liquid mixed carrying container (1), an articulated fracture channel (2), a vertical loading device (3), a volume pressure control device (4), a displacement stress controller (5) and a main control computer (6); The vertical loading device (3) is arranged on the top of the visualized solid-liquid mixing carrying container (1); the vertical loading device (3) is electrically connected to the displacement stress controller (5); A pressurizing valve (101), a water outlet valve (102) and a plurality of pore water pressure sensors (103) are arranged on the left side wall of the visualized solid-liquid mixing container (1); a water supply pipeline is connected between the pressurizing valve (101) and the volume pressure control device (4); and the pore water pressure sensor (103) is electrically connected to the volume pressure control device (4); The lower end of the visualized solid-liquid mixture carrying container (1) is provided with a waterproof groove bottom plate (104); the upper part of the hinged crack channel (2) is arranged in the groove of the waterproof groove bottom plate (104); a water-sand mixture collection box (7) is arranged below the lower part of the hinged crack channel (2); a drainage pipe is arranged at the bottom of the water-sand mixture collection box (7); the drainage pipe is connected to a water collecting box (8); The volume pressure control device (4) and the displacement stress controller (5) are electrically connected to the main control computer (6) respectively.

2. The loose layer seepage stability testing device according to claim 1 is characterized in that: The visualized solid-liquid mixing container (1) further comprises a cover plate (105) and a container ring wall (106); the cover plate (105) and the container ring wall (106) are fixedly connected to form a cavity; a sealing rubber ring is provided on the contact surface between the cover plate (105) and the container ring wall (106); a through hole is provided at the center of the cover plate (105); a pressure relief ball valve (107) and a plurality of pressure measuring tubes (108) are provided on the right side of the visualized solid-liquid mixing container (1); and the inner cavity of the visualized solid-liquid mixing container (1) is connected to the groove of the waterproof groove bottom plate (104).

3. The loose layer seepage stability testing device according to claim 1 is characterized in that: The hinged crack channel (2) comprises two adjustable channel arms (21); the adjustable channel arms (21) comprise at least three water-proof sliding hinge plates (211), at least two crack channel hinge plates (212) and at least three threaded rods (213); the two ends of the crack channel hinge plate (212) are respectively hinged to the upper surface or the lower surface of one end of two adjacent water-proof sliding hinge plates (211); the other end of the water-proof sliding hinge plate (211) is fixedly connected to one end of the threaded rod (213); limiting strips (214) are provided on both sides of the water-proof sliding hinge plate (211); the limiting strips (214) correspond to the limiting grooves (109) on the groove side walls of the waterproof groove bottom plate (104); and the crack channel hinge plate (212) is provided with a storage groove (215).

4. The loose layer seepage stability testing device according to claim 2 is characterized in that: The vertical loading device (3) comprises a loading base (301), a pressure column (302), a loading pressure head (303), a loading piston (304), a loading oil cylinder (305) and a pressure sensor (306); one end of the pressure column (302) passes upward through a through hole in the center of the cover plate (105), and a sealing device is provided at a contact surface between the cylindrical surface of the pressure column (302) and the through hole; the upper surface of the loading base (301) is fixedly connected to the other end of the pressure column (302); The loading base (301) is placed at the lower end of the cover plate (105); the loading pressure head (303) is placed at the upper end of the pressure-bearing column (302); the upper part of the loading piston (304) is sleeved in the loading oil cylinder (305); the lower end of the loading piston (304) is fixedly connected to the loading pressure head (303); the pressure sensor (306) is placed inside the loading oil cylinder (305); and the pressure sensor (306) is electrically connected to the displacement stress controller (5).

5. The loose layer seepage stability testing device according to claim 3 is characterized in that: It also includes a supporting steel frame (9); the upper part of the vertical loading device (3), the bottom of the water-sand mixture collecting box (7) and the bottom of the waterproof groove bottom plate (104) are respectively fixedly connected to the supporting steel frame (9).

6. The loose layer seepage stability testing device according to claim 5, characterized in that: It also comprises a plurality of adjustable connecting rods (22); the adjustable connecting rods (22) comprise a different direction hinged tube clamp (221), a double-hole hinged rod (222) and a single-side hinged rod (223); the different direction hinged tube clamp (221) is fixedly connected to a support column of the support steel frame (9); the hinge hole (224) of the different direction hinged tube clamp (221) is hinged to one end of the double-hole hinged rod (222); the other end of the double-hole hinged rod (222) is hinged to one end of the single-side hinged rod (223); the other end of the single-side hinged rod (223) is hinged to the threaded rod (213).

7. The loose layer seepage stability testing device according to claim 1 is characterized in that: The water-sand mixture collection box (7) comprises a box body (701) and a filtering device (702); the filtering device (702) comprises a plurality of hanging long arms (703) and a water-permeable plate (704); the lower end of the hanging long arm (703) is fixedly connected to the water-permeable plate (704); the upper end of the hanging long arm (703) is provided with a hook (705), and the hook (705) is hung on the top end of the ring wall of the box body (701).

8. The loose layer seepage stability testing device according to claim 1, characterized in that: The bottom of the water-sand mixture collection box (7) and the bottom of the water collection box (8) are both provided with precision weighing devices; and at least one high-speed camera is provided around the visual solid-liquid mixing carrying container (1).

9. A loose layer seepage stability test method, characterized in that: The loose layer seepage stability testing device applied to any one of claims 1 to 8, wherein the testing method comprises: The sand sample is placed in a visualized solid-liquid mixing carrying container, and a drainage experiment and a deep loose layer seepage experiment are performed on the sand sample based on the loose layer seepage stability testing device to obtain experimental data; According to the experimental data, the seepage stability of the loose layer is determined by using the structural stability judgment formula.

10. The loose layer seepage stability testing method according to claim 9, characterized in that: The experimental data at least include the average particle size of the sand sample particles, the bottom area of ​​the visualized solid-liquid mixing carrying container, the total mass of the vertical loading device, the distance between the initial free liquid surface position and the bottom plate of the waterproof groove, the bulk density of water, the friction coefficient of the sand particles, the water pressure at the free liquid surface position, the water pressure at the bottom plate of the waterproof groove, the crack width and the diameter of the visualized solid-liquid mixing carrying container; The method of determining the seepage stability of the loose layer by using a structural stability judgment formula based on the experimental data includes: According to the experimental data, vertical force, friction force, matrix suction, osmotic pressure and water pressure are obtained; determining the sum of stresses based on the vertical force, friction force, matrix suction, osmotic pressure and water pressure; According to the experimental data, the friction force and the sum of the stress, the seepage stability of the loose layer is determined by a structural stability judgment formula; the structural stability judgment formula is: ； Among them, F is the state value, F ≥ 0 means the loose layer structure is in an unstable state, and F < 0 means the loose layer structure is in a stable state; is the sum of stresses; D is the crack width; L is the diameter of the visualized solid-liquid mixing container; For friction.

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