A simulation experimental system and method for soil water response to groundwater level changes

Abstract

The present invention provides a soil water response to groundwater level change simulation experiment system and method, the system includes a column module, a water supply module, a monitoring module and a movable device module. The column module is a prismatic structure with a sealed bottom and an open top, including a column, the column is used to hold experimental soil; the lower part of the column is provided with a water injection port and a drainage port; the bottom of the column is provided with a vertically retractable oil bag, the upper part of the oil bag is provided with a rubber plug, and the oil bag is connected to a diversion box and a hydraulic pump in sequence; the method includes the following steps: similar simulation model laying, initial head height determination, model excavation, water level change and soil moisture content monitoring. The system and method provided by the present invention can simulate the coal mining process, have a certain reference value for studying the response mechanism of soil moisture to groundwater level changes, and have broad application prospects in the coal industry.

Description

Technical Field

[0001] The invention relates to the technical field of column simulation tests, and in particular to a simulation test system and method for soil water response to groundwater level changes. Background Art

[0002] Underground coal mining in the arid and semi-arid areas of western China has caused varying degrees of damage to the aquifers overlying the coal seams and the surface soil layers, forming coal mining subsidence areas. The water in the soil in the subsidence area has a capillary action from bottom to top, affecting the growth of surface vegetation and ground facilities. Therefore, exploring the response mechanism of soil moisture in coal mining subsidence areas to groundwater level changes is of great significance in terms of environmental protection and groundwater development. The existing simulation devices for the response of soil moisture to groundwater level changes are mostly column capillary test monomer devices. There is a lack of devices that restore the real appearance of coal mining subsidence areas, and it is impossible to simulate the coal mining process. There is also a lack of experimental models for the response of soil moisture in coal mining subsidence areas to groundwater level changes. Summary of the invention

[0003] Purpose of the invention: The technical problem to be solved by the present invention is to provide a simulation experimental system and method for the response of soil water to groundwater level changes in response to the deficiencies in the prior art, so as to solve the problem that traditional columns cannot simulate the coal mining process and restore the subsidence appearance of the coal mining area, and cannot simulate the response of soil moisture in the coal mining subsidence area to groundwater level changes.

[0004] The present invention provides a simulation experiment system for soil water response to groundwater level change, comprising a column module, a water supply module, a monitoring module and a movable device;

[0005] The column module is a prism structure with a sealed bottom and an open top, comprising a column, which is used to hold experimental soil;

[0006] The lower part of the column is provided with a water injection port and a water discharge port;

[0007] A vertically retractable oil bag is provided at the bottom of the column, a rubber plug is provided on the top of the oil bag, and the oil bag is connected to the diverter box and the hydraulic pump in sequence;

[0008] The water supply module includes a bracket, a water tank and a pipeline; the water tank is installed on the upper part of the bracket, and the lower side wall of the water tank is provided with a water outlet, and the water outlet is connected to the pipeline;

[0009] The monitoring module includes a water rate sensor and a data collector, and the water rate sensor and the data collector are connected via a connecting line;

[0010] The movable device comprises a bottom plate and universal wheels, the column and the bracket are fixed on the bottom plate, and the universal wheels are fixed under the bottom plate.

[0011] In order to accurately simulate different mining heights, the oil bags are ten monomer oil bags, which are respectively recorded as the first monomer oil bag to the tenth monomer oil bag from top to bottom. The monomer oil bags are made of polyurethane material. The bottom oil bag is the tenth monomer oil bag. The expansion thickness of the tenth monomer oil bag and the rubber plug is 1 cm. The expansion thickness of the remaining first monomer oil bag to ninth monomer oil bag is 2 cm. The compressive strength of a single oil bag is 800-1000 Pa.

[0012] The rubber plug is a watertight piston.

[0013] A liquid inlet is arranged at the front end of each monomer oil bag, and a liquid outlet is arranged at the rear end, and the liquid inlet and the liquid outlet are respectively connected to a diverter box controlled by a hydraulic pump.

[0014] The support is a single-leg support.

[0015] A sleeve is welded on the outer side wall of the water tank, and a buckle is fixed on the lower part.

[0016] The head end and tail end of the pipeline are respectively connected to the water outlet and the water inlet, and the head end is provided with a water valve.

[0017] The pipeline is made of soft rubber material.

[0018] The column is made of a transparent acrylic plate, and the side wall has centimeter scale lines. In order to prevent the oil bag from blocking the outflow of water, the water inlet and the drain outlet are arranged on the side wall and the rear position 20 cm from the bottom of the column respectively, and water rate sensors are arranged equidistantly on the inner wall along the vertical direction.

[0019] The present invention also provides a simulation experimental method for soil water response to groundwater level change, which is implemented using the system and includes the following steps:

[0020] Step 1. Before the experiment begins, determine the geometric similarity ratio based on the size of the coal seam engineering prototype and model. Combined with the geological conditions of the coal mine and the experience of related papers, select river sand and mica powder as similar material aggregates, calcium carbonate and gypsum as cementing materials, and borax as retarder. According to the hardness and physical and mechanical properties of the overlying rock strata of the coal seam, artificially proportion the similar materials according to experience, select the required number and number of monomer oil bags according to the similar mining height, open the diverter box and hydraulic pump, and control the oil to be injected into the selected oil bag; lay similar experimental materials in layers in the column, and arrange water rate sensors at a fixed height at the same time, and tamp the soil once after laying each layer;

[0021] Step 2: Fill the water tank with water, open the valve, and turn on the water rate sensor to record data; open the buckle, manually move the water tank up and down appropriately, so that the liquid level of the column (i.e., the simulated groundwater level) reaches the set position of the groundwater level in the coal mining area, and then close the buckle and the water valve;

[0022] Step 3: Use the diverter box to control the hydraulic pump to pump out the oil in the oil bag, and the soil in the column naturally falls to simulate the coal mining subsidence area. Then, open the drainage port at the bottom of the column and record the water rate sensor data in real time;

[0023] Step 4, repeating steps 1 to 3, and during the repetition, changing the initial liquid level height in the column in step 2;

[0024] Step 5, record the data recorded before the oil is extracted into an Excel table according to the serial number column, title column, line number column, point number column, east coordinate, north coordinate and water content, and import it into Sufer software for interpolation processing to obtain the distribution characteristics of water content of each stratum when the mining area is not mined; draw the data of the sensor after the drain outlet is opened into a curve, and the real-time change data of each sensor is a group to obtain the change law of water content of different strata in the mine subsidence area with the decline of groundwater level; record the change data of water content response to the decline of groundwater level under different initial water level conditions of the same stratum as a group to obtain the difference in the response law of soil moisture in the subsidence area with the decline of water level under different initial water level conditions.

[0025] Beneficial effects: The present invention provides a simulation experimental system and method for the response of soil water to groundwater level changes, which can not only restore the coal mining process and the subsidence appearance of the coal mining area, but also simulate the response of soil moisture in the coal mining subsidence area to groundwater level changes, providing a new research method for studying the impact of coal mining on water resources and the impact of groundwater level on the soil in the coal mining area, and providing certain value for the environmental protection of mining areas, especially the ecologically fragile mining areas in the west. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0027] Figure 1 It is the layout diagram of the simulation experiment system for the response of soil moisture in coal mining subsidence area to groundwater level changes;

[0028] Figure 2 This is the main view of the simulation experimental system for the response of soil moisture in coal mining subsidence areas to groundwater level changes;

[0029] Figure 3 It is an enlarged view of the main view of the oil bag of the simulation experimental system for the response of soil moisture in coal mining subsidence areas to groundwater level changes;

[0030] Figure 4 It is an enlarged schematic diagram of the water supply module of the simulation experimental system for the response of soil moisture in coal mining subsidence areas to groundwater level changes;

[0031] Figure 5This is a schematic diagram of the oil bag device in the simulation experiment system of the response of soil moisture in coal mining subsidence areas to groundwater level changes during use

[0032] Figure 1 to Figure 5 In the middle: 1-column, 2-oil bag, 3-rubber plug, 4-liquid inlet, 5-diverter box, 6-hydraulic pump, 7-bracket, 8-water tank, 9-water outlet, 10-water valve, 11-rubber hose, 12-water inlet, 13-sensor, 14-connecting line, 15-data collector, 16-base, 17-universal wheel, 18-liquid outlet, 19-sleeve, 20-buckle, 21-drainage outlet, 22-31-monomeric oil bag. DETAILED DESCRIPTION

[0033] like Figure 1 , Figure 2 As shown, the present invention provides a simulation experimental system for soil water response to groundwater level change, including a column module, a water supply module, a monitoring module and a movable device;

[0034] The column module is a prism structure with a sealed bottom and an open top, comprising a column 1, which is used to hold experimental soil;

[0035] The lower part of the column 1 is provided with a water injection port 12 and a water discharge port 21;

[0036] The bottom of the column 1 is provided with a vertically retractable oil bag 2, the upper part of the oil bag 2 is provided with a rubber plug 3, and the oil bag 2 is connected to the diverter box 5 and the hydraulic pump 6 in sequence;

[0037] The water supply module includes a bracket 7, a water tank 8 and a pipeline 11; the water tank 8 is installed on the upper part of the bracket 7, and the lower side wall of the water tank 8 is provided with a water outlet 9, and the water outlet 9 is connected to the pipeline 11;

[0038] The monitoring module includes a water rate sensor 13 and a data collector 15, and the water rate sensor 13 and the data collector 15 are connected via a connecting line 14;

[0039] The movable device comprises a bottom plate 16 and universal wheels 17 . The column 1 and the bracket 7 are fixed on the bottom plate 16 , and the universal wheels 17 are fixed under the bottom plate 16 .

[0040] In order to accurately simulate different mining heights, the oil bag 2 is composed of ten monomer oil bags, which are respectively recorded as the first monomer oil bag 22 to the tenth monomer oil bag 31 from top to bottom. The monomer oil bag is made of polyurethane material. The bottom oil bag is the tenth monomer oil bag 31. The expansion thickness of the tenth monomer oil bag 31 and the rubber plug 3 is 1 cm. The expansion thickness of the remaining first monomer oil bags 22 to ninth monomer oil bags 30 is 2 cm. The compressive strength of a single oil bag is 800-1000 Pa.

[0041] The rubber plug 3 is a watertight piston.

[0042] A liquid inlet 4 is arranged at the front end of each monomer oil bag, and a liquid outlet 18 is arranged at the rear end. The liquid inlet 4 and the liquid outlet 18 are respectively connected to the diverter box 5 controlled by the hydraulic pump 6 .

[0043] The bracket 7 is a single-leg bracket.

[0044] A sleeve 19 is welded to the outer wall of the water tank 8, and a buckle 20 is fixed at the lower part.

[0045] The head end and tail end of the pipeline 11 are respectively connected to the water outlet 9 and the water inlet 12, and a water valve 10 is provided at the head end.

[0046] The pipeline 11 is made of soft rubber material.

[0047] The column 1 is made of a transparent acrylic plate, and the side wall has centimeter scale lines. In order to prevent the oil bag from blocking the outflow of water, the water inlet 12 and the drain outlet 21 are respectively arranged on the side wall and the rear position 20 cm from the bottom of the column 1, and the water rate sensors 13 are evenly arranged on the inner wall in the vertical direction.

[0048] The present invention also provides a simulation experimental method for soil water response to groundwater level change, which is implemented using the system and includes the following steps:

[0049] Step 1, before the experiment begins, determine the geometric similarity ratio according to the size of the coal seam engineering prototype and model, combine the coal mine geological conditions and relevant paper experience, select river sand and mica powder as similar material aggregates, select calcium carbonate and gypsum as cementing materials, and select borax as retarder. According to the hardness and physical and mechanical properties of the overlying rock strata of the coal seam, artificially proportion the similar materials according to experience, select the required number and number of monomer oil bags according to the similar mining height, open the diverter box 5 and the hydraulic pump 6, and control the oil to be injected into the selected oil bag; lay similar experimental materials in layers in the column 1, and arrange the water rate sensor 13 at a fixed height at the same time, and tamp the soil once after laying each layer;

[0050] Step 2, fill the water tank 8 with water, open the valve 10, and turn on the water rate sensor 13 to record data; open the buckle 20, manually move the water tank 8 up and down appropriately, so that the liquid level of the column 1 (i.e., the simulated groundwater level) reaches the set position of the groundwater level in the coal mining area, and then close the buckle 20 and the water valve 10;

[0051] Step 3, use the diverter box 5 to control the hydraulic pump 6 to pump out the oil in the oil bag, and the soil in the column 1 naturally falls to simulate the coal mining subsidence area, and then open the drain port 21 at the bottom of the column 1, and record the data of the water rate sensor 13 in real time;

[0052] Step 4, repeating steps 1 to 3, and during the repetition, changing the initial liquid level in the column 1 in step 2;

[0053] Step 5, record the data recorded before the oil is extracted into an Excel table according to the serial number column, title column, line number column, point number column, east coordinate, north coordinate and water content column, and import it into Sufer software for interpolation processing to obtain the distribution characteristics of water content of each stratum when the mining area is not mined; draw the data of the sensor after the drain port 21 is opened into a curve, and the real-time change data of each sensor is a group to obtain the change law of water content of different strata in the mine subsidence area as the groundwater level drops; record the change data of water content response to groundwater level drop under different initial water level conditions of the same stratum as a group to obtain the difference in the response law of soil moisture in the subsidence area as the water level drops under different initial water level conditions.

[0054] In a specific embodiment of the present invention, Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 As shown, a simulation experiment system for soil water response to groundwater level change is provided, including a column module, a water supply module, a monitoring module and a movable device. The column 1 is a prism structure with a sealed bottom and an open top. Ten vertically retractable monomer oil capsules 2 are arranged at the bottom. The manufacturing material is polyurethane material. From top to bottom, they are respectively recorded as the first monomer oil capsule 22 to the tenth monomer oil capsule 31. The manufacturing material of the monomer oil capsule is polyurethane material. The bottom oil capsule is the tenth monomer oil capsule 31. The expansion thickness of the tenth monomer oil capsule 31 and the rubber plug 3 is 1 cm. The expansion thickness of the remaining first monomer oil capsule 22 to ninth monomer oil capsule 30 is 2 cm. The compressive strength of a single oil capsule is 800-1000 Pa. Figure 3 , 5 As shown, a waterproof movable rubber plug 3 is provided on the upper part of the oil bag 2;

[0055] Each oil bag is provided with a liquid inlet 4 at the front end and a liquid outlet 18 at the rear end, and is connected to a diverter box 5 controlled by a hydraulic pump 6 .

[0056] The water supply module comprises a bracket 7, a water tank 8 and a pipeline 11. The bracket 7 is a single-leg bracket, and the water tank 8 is arranged on the upper part. A sleeve 19 is welded to the outer wall of the water tank 8, and a buckle 20 is fixed to the lower part.

[0057] A water outlet 9 is provided at the lower part of the other side of the water tank 8, and the water outlet 9 is connected to the head end of a pipe 11. The pipe 11 is made of a rubber soft material, has a valve 10 at the head end, and is connected to a water inlet 12 at the tail end. Figure 4 shown.

[0058] The connection line 14 in the monitoring module is connected to the water rate sensor 13 and the data collector 15. The water rate sensor 13 is arranged equidistantly along the vertical direction on the inner wall. The movable device includes a bottom plate 16 and a universal wheel 17. The column 1 and the bracket 7 are fixed on the bottom plate 16, and the universal wheel 17 is fixed under the bottom plate 16.

[0059] In another specific embodiment of the present invention, if the thickness of a coal seam in a coal mine is 10m, the thickness and lithology of the overlying rock layers are 5m sandstone, 10m medium sandstone, 8m sandy mudstone, 20m coarse sandstone, 15m sandstone, 12m siltstone, 6m fine sandstone, 16m medium sandstone, 8m topsoil layer from bottom to top, and the groundwater level is 60m from the coal seam floor. First, before the experiment begins, the similarity ratio is determined to be 20:1 according to the engineering prototype, and the similar mining height is 5cm. The tenth monomer oil bladder 31, the ninth monomer oil bladder 30, and the eighth monomer oil bladder 29 are selected. The diverter box 5 and the hydraulic pump 6 are opened to control the oil to be injected into the selected oil bladder. Similar experimental materials are laid in layers in the column 1, and water rate sensors are arranged every 10cm. Each layer of similar materials is compacted once.

[0060] Then, a proper amount of water is poured into the water tank 8, the valve 10 is opened, and the water rate sensor 13 is turned on to record data, and water is then added to the column 1. The buckle 20 is opened, and the water tank 8 is manually moved up and down appropriately to make the liquid level of the column 1 (i.e., the simulated groundwater level) reach the 30 cm scale line position. After the liquid level is stabilized at 30 cm, the buckle 20 and the water valve 10 are closed to stop the water supply.

[0061] Finally, the hydraulic pump 6 is controlled by the diverter box 5 to pump out the oil in the oil bag, and the soil in the column 1 falls naturally to simulate the coal mining subsidence area. Then, the drain port 21 at the bottom of the column 1 is opened, and the data of the water rate sensor 13 is recorded in real time.

[0062] The data recorded before the oil is extracted are recorded in Excel according to the serial number column, title column, line number column, point number column, east coordinate, north coordinate and water content, and imported into Sufer software for interpolation processing to obtain the distribution characteristics of water content of each stratum when the mining area is not mined; the data of the sensor after the drain outlet 21 is opened is plotted into a curve, and the real-time change data of each sensor is a group to obtain the change law of water content of different strata in the subsidence area of ​​the mine with the decline of groundwater level; the response change data of water content of the same stratum with the decline of groundwater level under different initial water level conditions are recorded as a group to summarize the differences in the response law of soil moisture in the subsidence area with the decline of water level under different initial water level conditions.

[0063] The present invention provides a simulation experiment system and method for the response of soil moisture in coal mining subsidence area to groundwater level changes. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A simulation experimental system for soil water response to groundwater level changes, characterized in that: It includes a column module, a water supply module, a monitoring module and a movable device; The column module is a prism structure with a sealed bottom and an open top, comprising a column (1), wherein the column (1) is used to contain soil for the experiment; The lower part of the column (1) is provided with a water injection port (12) and a water discharge port (21); The bottom of the column (1) is provided with an oil bag (2) which is retractable in the vertical direction, the upper part of the oil bag (2) is provided with a rubber plug (3), and the oil bag (2) is connected to a diverter box (5) and a hydraulic pump (6) in sequence; The water supply module comprises a bracket (7), a water tank (8) and a pipeline (11); the water tank (8) is installed on the upper part of the bracket (7), and a water outlet (9) is provided on the lower side wall of the water tank (8), and the water outlet (9) is connected to the pipeline (11); The monitoring module comprises a water rate sensor (13) and a data collector (15), wherein the water rate sensor (13) and the data collector (15) are connected via a connecting line (14); The movable device comprises a bottom plate (16) and a universal wheel (17), the column (1) and the bracket (7) are fixed on the bottom plate (16), and the universal wheel (17) is fixed under the bottom plate (16); In order to accurately simulate different mining heights, the oil bladder (2) is composed of ten monomer oil bladders, which are respectively recorded as the first monomer oil bladder (22) to the tenth monomer oil bladder (31) from top to bottom. The monomer oil bladders are made of polyurethane material. The bottommost oil bladder is the tenth monomer oil bladder (31). The expanded thickness of the tenth monomer oil bladder (31) and the rubber plug (3) is 1 cm. The expanded thickness of the remaining first monomer oil bladders (22) to the ninth monomer oil bladder (30) is 2 cm. The compressive strength of a single oil bladder is 800 to 1000 Pa. The rubber plug (3) is a watertight piston; Each monomer oil bag is provided with a liquid inlet (4) at the front end and a liquid outlet (18) at the rear end, and the liquid inlet (4) and the liquid outlet (18) are respectively connected to a diverter box (5) controlled by a hydraulic pump (6); The bracket (7) is a single-leg bracket; A sleeve (19) is welded to the outer wall of the water tank (8), and a buckle (20) is fixed at the lower part; The head end and tail end of the pipeline (11) are respectively connected to the water outlet (9) and the water injection port (12), and the head end is provided with a water valve (10); The pipeline (11) is made of a soft rubber material; The column (1) is integrated with a water rate sensor (13) and a connecting line (14). The column (1) is made of a transparent acrylic plate, and the side wall has centimeter scale lines. In order to prevent the oil bag from blocking the outflow of water, the water inlet (12) and the water outlet (21) are respectively arranged on the side wall and the rear position of the bottom 20 cm of the column (1). One side wall of the column (1) is thickened, and the inner side wall is evenly spaced along the vertical direction. The connecting line (14) is inside the side wall.

2. A method for simulating the response of soil water to groundwater level changes, implemented using the system as claimed in claim 1, characterized in that: The following steps are involved: Step 1, before the experiment begins, determine the geometric similarity ratio according to the size of the coal seam engineering prototype and model, mix similar materials, select the required number and number of single oil bags according to similar mining heights, open the diverter box (5) and the hydraulic pump (6), and control the oil to be injected into the selected oil bags; lay similar experimental materials in layers in the column (1), and arrange a water rate sensor (13) at a fixed height, and tamp the soil once after each layer is laid; Step 2, fill the water tank (8) with water, open the water valve (10), and simultaneously open the water rate sensor (13) to record data; open the buckle (20), manually move the water tank (8) up and down appropriately, so that the liquid level of the column (1) (i.e., the simulated groundwater level) reaches the set position of the groundwater level in the coal mining area, and then close the buckle (20) and the water valve (10); Step 3, using the diverter box (5) to control the hydraulic pump (6) to pump out the oil in the oil bag, the soil in the column (1) naturally falls down to simulate the coal mining subsidence area, and then the drainage port (21) at the bottom of the column (1) is opened to record the data of the water rate sensor (13) in real time; Step 4, repeating steps 1 to 3, and during the repetition, changing the initial liquid level in the column (1) in step 2; Step 5, record the data recorded before the oil is extracted into an Excel table according to the serial number column, title column, line number column, point number column, east coordinate, north coordinate and water content column, and import it into Sufer software for interpolation processing to obtain the distribution characteristics of water content of each stratum when the mining area is not mined; draw the data of the sensor after the drain port (21) is opened into a curve, and the real-time change data of each sensor is a group to obtain the change law of water content of different strata in the mine subsidence area as the groundwater level drops; record the change data of water content response to groundwater level drop under different initial water level conditions of the same stratum as a group to obtain the difference in the response law of soil moisture in the subsidence area as the water level drops under different initial water level conditions.

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