CN113823166B

CN113823166B - Simulation device for covering type karst collapse caused by water level fluctuation

Info

Publication number: CN113823166B
Application number: CN202111158195.9A
Authority: CN
Inventors: 张云峰; 焦玉国; 王延岭; 邢立亭; 赵新村; 张学明; 赵志伟; 吴亚楠; 刘蛟; 于苗; 黄林显
Original assignee: University of Jinan; Fifth Geological Brigade of Shandong Provincial Bureua of Geology and Mineral Resources of Fifth Geological and Mineral Exploration Institute of Shandong Province
Current assignee: University of Jinan; Fifth Geological Brigade of Shandong Provincial Bureua of Geology and Mineral Resources of Fifth Geological and Mineral Exploration Institute of Shandong Province
Priority date: 2021-09-30
Filing date: 2021-09-30
Publication date: 2023-02-24
Anticipated expiration: 2041-09-30
Also published as: CN113823166A

Abstract

The invention discloses a simulation device for covering type karst collapse caused by water level fluctuation, and relates to the technical field of hydrology and geology. The device includes the analog unit, the inner space of analog unit's test box is cut apart into dive simulation district, confined water simulation district and filtering area by first baffle and second baffle, the dive simulation district in be provided with the soil body, just first baffle on be provided with and dissolve hole simulation hole. Be provided with the seepage flow section of thick bamboo of arranging with the solution cavity simulation hole coaxial on the first baffle, it is provided with first hole and the second hole that leaks respectively to lie in the pressure-bearing water simulation district and filtering area on the lateral wall of seepage flow section of thick bamboo, seepage flow section of thick bamboo in be provided with the piston, the piston from last shutoff ring and the shutoff board of down including in proper order, shutoff ring and shutoff board between be provided with the connecting rod. The device can collect the soil body that the fluctuation of water level dropped at every turn to carry out quantitative analysis and judgement to the development process that the karst sinks.

Description

Simulation device for covering type karst collapse caused by water level fluctuation

Technical Field

The invention relates to the technical field of hydrology and geology, in particular to a simulation device for covering type karst collapse caused by water level fluctuation.

Background

Karst collapse refers to sudden ground deformation damage caused by balance damage of loose soil bodies covering a corrosion cave under the action of external power or human factors, and a conical collapse pit is formed as a result. The cause of karst collapse is many, and the flow of groundwater and the change of hydrodynamic conditions thereof are the most important dynamic factors for the formation of karst collapse, so that zones with concentrated groundwater runoff and strong ground water runoff are most prone to collapse.

The cause of karst collapse is hidden and is difficult to be found in the early stage, so the karst collapse is often suddenly caused in the aspect of appearance, which not only threatens the personal safety, but also damages road traffic engineering and the like. Therefore, people carry out a series of researches on the cause and the development process of karst collapse, but the particularity of the karst collapse is incapable of being researched on the spot, so that a simulation device is generally used for carrying out laboratory simulation on the karst collapse process, so that the cause and the development process of the karst collapse are researched and explored, and scientific basis can be provided for the prediction of the karst collapse in actual production life.

The existing simulation device for simulating karst collapse is generally used for qualitatively observing the change condition of the soil surface by simply changing the flow and hydrodynamic conditions of underground water. This is mainly problematic in several respects:

firstly, the change condition of the soil surface is qualitatively observed, so that the method has little guiding significance for actual production.

Secondly, even if quantitative observation can be performed on the change condition of the soil body surface, the karst collapse process is that the soil on the lower surface of the soil body firstly falls to form a reverse pot hole as shown in fig. 22, and at the moment, the upper surface of the soil body is not changed or slightly changed, so that the change condition of the upper surface of the soil body is difficult to observe, which is also the reason that the karst collapse has the suddenness.

Disclosure of Invention

Aiming at the problems, the invention provides a simulation device for covering type karst collapse caused by water level fluctuation, which can collect soil bodies falling by water level fluctuation each time, thereby carrying out quantitative analysis and judgment on the development process of karst collapse.

The technical scheme adopted by the invention for solving the technical problem is as follows:

a simulation device for covering type karst collapse caused by water level fluctuation comprises a simulation unit, wherein the inner space of a test box body of the simulation unit is divided into a diving simulation area, a confined water simulation area and a filtering area by a first partition plate and a second partition plate, a soil body is arranged in the diving simulation area, and a karst cave simulation hole is formed in the first partition plate;

the first partition plate is provided with a seepage cylinder coaxially arranged with the karst cave simulation hole, the side wall of the seepage cylinder is respectively provided with a first water leakage hole and a second water leakage hole in the pressure-bearing water simulation area and the filtering area, a piston is arranged in the seepage cylinder, the piston sequentially comprises a plugging ring and a plugging plate from top to bottom, and a connecting rod is arranged between the plugging ring and the plugging plate;

there are two working positions of the tool holder,

when the piston is in a first working position, the first water leakage hole is blocked by the blocking ring, and the second water leakage hole is positioned between the blocking ring and the blocking plate;

when the piston is in the second working position, the pressure-bearing water simulation area and the filtering area are isolated by the plugging plate, and the first water leakage hole is positioned between the plugging ring and the plugging plate.

Furthermore, a water outlet is formed in a bottom plate of the test box body, and a detachable filter box is arranged at the water outlet.

Furthermore, the bottom surface of the filter box is provided with filter holes, filter paper is laid in the filter box, the bottom surface of the test box body is provided with a connecting cylinder, and the connecting cylinder is inserted into the filter box and is in sealing connection with the filter box.

Furthermore, the bottom plate of the test box body is of a conical structure, the water outlet is formed in the lowest point of the conical structure, and the upper side face of the blocking plate is a spherical face or a conical face.

Further, still include the body frame body, the analog unit set up in the body frame body on, the body frame body on slide and be provided with the water supply water tank, the body frame body on be provided with and be used for driving gliding drive unit about the water supply water tank, the water supply water tank cut apart into water supply area and return water district by the overflow plate, water supply area in be provided with water inlet and delivery port, return water district in be provided with the return water mouth, the delivery port respectively through second pipeline and third pipeline with dive analog domain and confined water analog domain be linked together.

Further, the water supply tank comprises a tank body, the driving unit comprises a lead screw rotatably arranged on the main frame body, a water-proof cylinder coaxially arranged with the lead screw is arranged in the tank body, the lower end of the water-proof cylinder is fixedly connected with the closed end of the tank body in a sealing manner, a through hole for accommodating the lead screw is formed in the closed end of the tank body, and a screw matched with the lead screw is fixedly arranged in the water-proof cylinder.

Further, guide rods are respectively arranged on two sides of the water supply water tank on the main frame body, guide seats matched with the guide rods are fixedly arranged on the barrel body, a driving motor is arranged on the main frame body, and a power output shaft of the driving motor is connected with the lead screw through a transmission mechanism.

Furthermore, a third partition plate is arranged in the diving simulation area, the diving simulation area is divided into a water distribution area and a test area by the third partition plate, water distribution holes are formed in the third partition plate, a soil body is arranged in the test area, and a water outlet of the water supply tank is communicated with the water distribution area through a second pipeline.

Furthermore, a spray pipe assembly used for simulating natural rainfall is arranged above the test area in the test box body.

Furthermore, the test box body is made of transparent materials, a traction rope is buried in the surface layer of the soil body, the projection of the traction rope in the horizontal plane passes through the circle center of the hole dissolving simulation hole, a plurality of indicating needles are evenly arranged on the traction rope, the upper ends of the indicating needles are exposed outside the soil body, and scales used for indicating the vertical size and the horizontal size are arranged on the test box body.

The beneficial effect of this aspect is:

1. the device can collect and weigh the soil body that the water level fluctuation dropped at every turn, establishes quantitative relation between the water level fluctuation and the soil body dropping condition, thereby carrying out quantitative analysis and judgment on the development process of karst collapse and providing a basis for deep exploration of the covering karst collapse mechanism.

2. The device is at the in-process that continues the collection to the soil body that drops, does not influence test process on next step, and the collection process and the test process of the soil body can go on simultaneously promptly, can effectual improvement work efficiency like this, and the operation process of reality is very convenient, only need promote the piston from top to bottom, alright in order to realize the switching of working process.

3. Design into quadrangular pyramid shape through the lower bottom surface with experimental box, and be used for collecting the rose box that drops the soil body and be located the minimum, can guarantee like this that the soil body that drops enters into the rose box completely to guarantee the accuracy of experimental data.

4. Because the collection process and the test process of the soil body of the device can be carried out simultaneously, the time enough for the collection process is reserved, and thus the filter paper can be arranged in the filter box, and the accuracy of the test data is further ensured.

5. The device not only can simulate confined water runoff, can also simulate dive runoff and natural rainfall, simulation groundwater that can be comprehensive flows and hydrodynamic force condition.

6. The device buries soft guide wire underground through the surface layer at the soil body to set up the pointer on the guide wire, and the upper end of pointer exposes in the outside of soil body, like this, can follow the audio-visual condition of subsiding of observing the pointer in experimental box outside, and can directly read data, this for common laser displacement sensor, not only guaranteed measured data's accuracy, can also audio-visual observation the condition of subsiding of soil body.

Drawings

FIG. 1 is a first schematic perspective view of a simulation apparatus;

FIG. 2 is a schematic perspective view of a simulation apparatus;

FIG. 3 is a right side view of the simulation apparatus;

FIG. 4 isbase:Sub>A sectional view A-A of FIG. 3;

FIG. 5 is a schematic perspective view of the simulation unit;

FIG. 6 is an enlarged schematic view of portion A of FIG. 5;

FIG. 7 is a front view of the simulation unit;

FIG. 8 is a cross-sectional view taken along line B-B of FIG. 7;

FIG. 9 is a cross-sectional view taken along line C-C of FIG. 7;

FIG. 10 is a left side view of the simulation unit;

FIG. 11 is a cross-sectional view taken along line D-D of FIG. 10;

FIG. 12 is an enlarged view of the portion B of FIG. 11;

FIG. 13 is a schematic structural diagram of the simulation unit when simulating confined water runoff;

FIG. 14 is an enlarged view of the portion C of FIG. 13;

FIG. 15 is a perspective view of a seepage cartridge;

FIG. 16 is a perspective view of the piston;

FIG. 17 is a schematic perspective view of the filter box;

fig. 18 is a schematic view of the internal structure of the water supply tank;

FIG. 19 is a schematic perspective view of the circulation tank;

fig. 20 is a schematic perspective view of the main frame body;

FIG. 21 is a schematic view of the position structure of the guide wire and the indicating needle;

fig. 22 is a schematic diagram showing the position change of the guide line and the indicator needle when the soil surface layer is deformed.

In the figure: 1-a main frame body, 111-a first square frame, 112-a second square frame, 113-a first upright post, 121-a third square frame, 122-a second upright post, 13-an installation beam, 131-a third upright post, 14-a support leg, 15-a baseboard, 16-an upper installation plate, 17-a lower installation plate, 18-a guide rod,

2-simulation unit, 21-test box, 211-connecting plate, 212-first reinforcing rib plate, 213-first water inlet pipe, 214-second water inlet pipe, 215-ear plate, 216-connecting cylinder, 221-first clapboard, 2211-cavern simulation hole, 222-second clapboard, 223-third clapboard, 2231-water distribution hole, 23-soil body, 231-hauling rope, 2311-indicator needle, 2411-water distribution area, 2412-test area, 242-pressure water simulation area, 243-filtering area, 251-branch pipe, 252-confluence pipe, 26-percolating cylinder, 261-first water leakage hole, 262-second water leakage hole, 27-piston, 271-plugging ring, 2711-first sealing ring, 2712-second sealing ring, 272-plugging plate, 2721-third sealing ring, 273-connecting rod, 274-handle, 28-filter box, 281-filter hole, 282-connecting ear, 291-holding rod, 292-holding rod, 2921-concave positioning pin,

3-a circulating water tank, 31-a limiting plate, 32-a second reinforcing rib plate,

4-a water supply tank, 41-a barrel body, 411-a water inlet, 412-a water outlet, 413-a water return port, 42-a water-stop cylinder, 43-an overflow plate, 441-a water inlet area, 442-a water return area, 45-a guide seat,

51-lead screw, 52-nut, 53-driving motor, 541-driving pulley, 542-driven pulley, 543-synchronous belt.

Detailed Description

For convenience of description, a coordinate system is defined as shown in fig. 1, and the left-right direction is taken as a transverse direction, the front-back direction is taken as a longitudinal direction, and the up-down direction is taken as a vertical direction.

As shown in fig. 1, 2 and 3, a simulation device for covering karst collapse caused by water level fluctuation comprises a main frame body 1, wherein a simulation unit 2 and a circulating water tank 3 are sequentially arranged on the main frame body 1 from top to bottom, a water supply tank 4 is arranged behind the simulation unit 2, the water supply tank 4 is slidably connected with the main frame body 1, and the water supply tank 4 can slide up and down relative to the main frame body 1. And a driving unit for driving the water supply tank 4 to slide up and down is arranged between the water supply tank 4 and the main frame body 1.

As a specific embodiment, as shown in fig. 20, the main frame 1 in this embodiment includes a support frame having a rectangular parallelepiped structure.

Preferably, the support frame from bottom to top includes first square frame 111 and second square frame 112 in proper order, first square frame 111 form by four first boundary beams end to end in proper order, second square frame 112 have four second boundary beams end to end in proper order and form. Four first upright posts 113 are arranged between the first square frame 111 and the second square frame 112, the four first upright posts 113 are respectively positioned at four corners, and the upper end and the lower end of the first upright post 113 are respectively fixedly connected with the second square frame 112 and the first square frame 111 in a welding manner.

A third square frame 121 formed by sequentially connecting four second side beams end to end is arranged above the supporting frame, second upright columns 122 extending downwards along the vertical direction are respectively arranged on four corners of the third square frame 121, and the lower ends of the second upright columns 122 are fixedly connected with the supporting frame.

The support frame on be located the left and right both sides of support frame are provided with respectively along longitudinal extension's installation roof beam 13, the front end of installation roof beam 13 pass through third stand 131 with support frame fixed connection, the rear end of installation roof beam 13 through welded mode with be located the second stand 122 fixed connection of front side.

The support frame is characterized in that a supporting leg 14 used for supporting the support frame is arranged on the lower side face of the support frame, and a base plate 15 is fixedly arranged on the lower end face of the supporting leg 14 in a welding mode.

The third square frame 121 is provided with an upper mounting plate 16, and the second square frame 112 is fixedly provided with a lower mounting plate 17 below the upper mounting plate 16.

As shown in fig. 5, 7 and 9, the simulation unit 2 includes a test box 21, connection plates 211 extending outward in the horizontal direction are respectively disposed on the left and right sides of the test box 21, and the connection plates 211 are fixedly connected to the mounting beams 13 of the main frame 1 by screws. Preferably, a plurality of first reinforcing rib plates 212 are arranged between the connecting plate 211 and the test box body 21.

Test box 21 in from last first baffle 221 and the second baffle 222 of down having set gradually, just first baffle 221 and second baffle 222 will the inner space of test box 21 is cut apart into dive simulation area, pressure-bearing water simulation area 242 and filtration area 243. The diving simulation area is internally provided with a third partition 223 extending in the vertical direction, the third partition 223 divides the diving simulation area into a front area and a rear area, namely a water distribution area 2411 and a test area 2412, as shown in fig. 11, and a plurality of water distribution holes 2231 are uniformly distributed on the third partition 223. Wherein the test area 2412 is provided with a soil mass 23 for simulating an overburden over an erosion cave.

And a spray pipe assembly for simulating natural rainfall is arranged above the test area 2412 in the test box body 21. The nozzle component comprises a plurality of branch pipes 251 extending along the left-right direction, and a plurality of nozzles are uniformly arranged on the branch pipes 251 along the axial direction. The left side wall and the right side wall of the test box body 21 are respectively provided with a mounting hole for accommodating the branch pipe 251. The left side or the right side of the test box 21 is provided with a collecting pipe 252 extending along the front-back direction, and the branch pipes 251 are respectively communicated with the collecting pipe 252.

Fixed seepage flow section of thick bamboo 26 that is provided with along vertical direction downwardly extending on the downside of first baffle 221, just seepage flow section of thick bamboo 26 the upper end with first baffle 221 sealed fixed connection, seepage flow section of thick bamboo 26's lower extreme passes in proper order the bottom plate of second baffle 222 and experimental box 21 extend to the below of experimental box 21, just seepage flow section of thick bamboo 26 respectively with second baffle 222 and bottom plate sealed connection.

As shown in fig. 9 and 15, the seepage cylinder 26 is a cylinder with an open upper end and a closed lower end, a plurality of first water leakage holes 261 are uniformly distributed on the sidewall of the seepage cylinder 26 in the pressure-bearing water simulation area 242, and the first water leakage holes 261 are all located on the lower half portion of the pressure-bearing water simulation area 242. A plurality of second water leakage holes 262 are uniformly distributed in the filtering area 243 on the side wall of the seepage cylinder 26.

As shown in fig. 9 and 16, a piston 27 is disposed in the seepage cartridge 26 and can slide up and down relative to the seepage cartridge 26. The piston 27 sequentially comprises a plugging ring 271 and a plugging plate 272 from top to bottom, the plugging ring 271 is of a cylindrical structure with two open ends, and the outer diameters of the plugging ring 271 and the plugging plate 272 are respectively matched with the inner diameter of the seepage cylinder 26, so that a guiding effect is achieved for the piston 27 to slide up and down. A plurality of connecting rods 273 are arranged between the blocking ring 271 and the blocking plate 272, and the plurality of connecting rods 273 are uniformly arranged along the circumferential direction. As a specific implementation manner, four connecting rods 273 are disposed between the blocking ring 271 and the blocking plate 272 in the embodiment. Fixed on the downside of shutoff board 272 is provided with along vertical direction downwardly extending's handle 274, just the lower extreme of handle 274 passes the blind end of a seepage flow section of thick bamboo 26 extends to the below of a seepage flow section of thick bamboo 26, be provided with on the blind end of a seepage flow section of thick bamboo 26 and be used for holding handle 274 dodge the hole.

Further, in order to ensure the sealing performance, as shown in fig. 12, a first sealing ring 2711 and a second sealing ring 2712 are sequentially arranged from top to bottom between the blocking ring 271 and the seepage cylinder 26, and a third sealing ring 2721 is arranged between the blocking plate 272 and the seepage cylinder 26. Preferably, a first annular groove and a second annular groove for accommodating the first sealing ring 2711 and the second sealing ring 2712 are respectively arranged on the outer cylindrical surface of the blocking ring 271, and a third annular groove for accommodating the third sealing ring 2721 is arranged on the outer cylindrical surface of the blocking plate 272.

As shown in fig. 9, a cavern simulating hole 2211 which is arranged coaxially with the infiltration cylinder 26 is arranged in the infiltration cylinder 26 on the first partition 221, and the cavern simulating hole 2211 is used for simulating a cavern opening in nature. The diameter of the hole-dissolving simulation hole 2211 is smaller than the inner diameter of the seepage cylinder 26.

As shown in fig. 5 and 9, a first water inlet pipe 213 and a second water inlet pipe 214 are respectively disposed on the rear side wall of the test box 21, wherein the first water inlet pipe 213 is communicated with a water distribution area 2411 of the diving simulation area, and the second water inlet pipe 214 is communicated with the bottom of the diving simulation area.

As shown in fig. 5, 10 and 11, a drain port is provided on the bottom plate of the test chamber body 21 above the circulation water tank 3, and a detachable filter tank 28 is provided at the drain port.

As a specific embodiment, as shown in fig. 17, the filter box 28 in this embodiment is a square box with an open upper side, and a plurality of filter holes 281 are uniformly distributed on the bottom surface of the filter box 28. The outer side surfaces of the front side wall and the rear side wall of the filter box 28 are respectively and fixedly provided with a connecting lug 282. As shown in fig. 6, the bottom plate of the test box 21 is provided with two ear plates 215 respectively located at the left and right sides of the connecting lug 282 and extending downward along the vertical direction, a positioning pin 291 is provided between the two ear plates 215, and the connecting lug 282 is provided with a positioning hole for accommodating the positioning pin 291.

Further, in order to facilitate the installation and removal of the filter box 28, as shown in fig. 7 and 8, a holding rod 292 is disposed between the two positioning pins 291 and on one side of the filter box 28, and the positioning pins 291 and the holding rod 292 form a U-shaped structure together.

Further, for convenience of operation, the holding rod 292 is provided with a concave portion 2921 that is concave toward a side away from the positioning pin 291.

Further, in order to ensure that the dropped soil 23 can be completely retained in the filter box 28, filter paper is laid in the filter box 28. Although it is possible to prevent fine soil particles from entering the circulation tank through the filter holes 281 and ensure the accuracy of the final data, the water level in the filter area 243 of the over-test tank 21 may be higher than the drain port of the test tank due to the slow draining speed of the filter paper, and thus, the tightness of the connection between the filter tank 28 and the drain port needs to be ensured. For this purpose, as shown in fig. 11, a connecting cylinder 216 extending downward in the vertical direction is provided on the bottom surface of the test box body 21 at the drain port, and the connecting cylinder 216 is inserted into the filter box 28 and forms a sealing connection with the filter box 28. Preferably, a fourth sealing ring is arranged between the connecting cylinder 216 and the sealing box.

Further, in order to prevent the dropped soil from being retained in the filtering area 243 of the test case 21, as shown in fig. 5 and 11, the bottom plate of the test case 21 is tapered, and the drain port is provided at the lowest point of the tapered structure. Preferably, the bottom plate of the test box 21 is a quadrangular pyramid structure or a conical structure, and as a specific embodiment, the bottom plate of the test box 21 in this embodiment is a quadrangular pyramid structure.

Similarly, in order to prevent the dropped soil portion from staying in the piston 27, as shown in fig. 12, the upper side surface of the blocking plate 272 is a spherical surface or a conical surface. As a specific implementation manner, the upper side surface of the blocking plate 272 in this embodiment is a spherical surface.

As shown in fig. 2, 3, 4, 18 and 20, the supply water tank 4 includes a tub 41, and the tub 41 has a cylindrical structure with an open upper end and a closed lower end. The driving unit comprises a lead screw 51 extending along the up-down direction, and two ends of the lead screw 51 are respectively connected with the upper mounting plate 16 and the lower mounting plate 17 in a rotating manner through bearing assemblies. The barrel body 41 is internally provided with a water-stop cylinder 42 which is coaxially arranged with the screw rod 51, the lower end of the water-stop cylinder 42 is fixedly connected with the closed end of the barrel body 41 in a sealing manner, the closed end of the barrel body 41 is provided with a through hole for accommodating the screw rod 51, and preferably, the diameter of the through hole is the same as the inner diameter of the water-stop cylinder 42. And a nut 52 matched with the screw 51 is fixedly arranged in the water-stop cylinder 42.

As shown in fig. 3 and 4, an overflow plate 43 is disposed between the water-stop cylinder 42 and the barrel 41, and the overflow plate 43 divides a space between the water-stop cylinder 42 and the barrel 41 into two parts, namely a water inlet area 441 and a water return area 442. A water inlet 411 and a water outlet 412 are arranged in the water inlet area 441 on the bottom surface of the barrel body 41, wherein the water inlet 411 is connected with the circulating water tank 3 through a first pipeline, and the water outlet 412 is connected with the first water inlet pipe 213, the second water inlet pipe 214 and the collecting pipe 252 on the test box 21 through a second pipeline, a third pipeline and a fourth pipeline respectively. The first pipeline is provided with a circulating pump used for pumping water into the water supply tank 4, and the second pipeline, the third pipeline and the fourth pipeline are respectively provided with a control valve used for controlling the on-off of the second pipeline, the third pipeline and the fourth pipeline. A water return port 413 is formed in the water return area 442 on the bottom surface of the barrel 41, and the water return port 413 is connected to the circulating water tank 3 through a fifth pipeline.

As shown in fig. 2, 4 and 20, guide rods 18 are respectively disposed on the left and right sides of the main frame 1 on the water supply tank 4, and the upper and lower ends of the guide rods 18 are respectively fixedly connected to the upper mounting plate 16 and the lower mounting plate 17. A guide seat 45 is fixedly arranged on the outer cylindrical surface of the barrel body 41 of the water supply tank 4, and a guide hole matched with the guide rod 18 is formed in the guide seat 45.

The upper mounting plate 16 is fixedly provided with a driving motor 53, and a power output shaft of the driving motor 53 passes through the upper mounting plate 16 and extends to the upper part of the upper mounting plate 16. A driving pulley 541 is fixedly arranged on a power output shaft of the driving motor 53, a driven pulley 542 is fixedly arranged at the upper end of the lead screw 51, and the driving pulley 541 is connected with the driven pulley 542 through a synchronous belt 543.

Further, as shown in fig. 19, limit plates 31 are respectively disposed on the left and right sides of the first square frame 111 on the bottom surface of the circulation tank 3, and a distance between the two limit plates 31 is equal to a dimension of the first square frame 111 in the left-right direction. A plurality of second reinforcing rib plates 32 are arranged between the limiting plate 31 and the bottom surface of the circulating water tank 3.

Further, in order to visually see the deformation of the surface of the soil 23, the test box 21 is made of a transparent material, and preferably, the test box 21 is made of an acrylic plate. As shown in fig. 21, a flexible hauling cable 231 is embedded in the surface layer of the soil body 23, and the projection of the hauling cable 231 in the horizontal plane passes through the center of the karst cave simulating hole 2211. As a specific implementation manner, the pulling rope 231 in this embodiment is a hemp rope without elasticity. A plurality of indicating needles 2311 extending upwards along the vertical direction are uniformly arranged on the hauling rope 231, and the upper ends of the indicating needles 2311 are exposed outside the soil body 23.

Preferably, the distance L between the hauling cable 231 and the upper surface of the soil body 23 is 1/5 of the thickness H of the soil body 23.

As shown in fig. 22, when the surface of the soil 23 is deformed under the influence of hydrodynamic conditions, the haulage rope 231 is flexible and non-elastic, and thus deforms along with the deformation of the soil 23, and at this time, the deformed haulage rope 231 sinks together with the pointer 2311. Because the indicator 2311 is vertically arranged and is slender and smooth, the friction force between the indicator and the soil 23 is small, and the deformation cannot be influenced.

Further, in order to facilitate measurement and observation, the front side surface of the test box 21 is provided with scales for indicating a vertical dimension and a horizontal dimension, so that the deformation amount can be directly read on the test box 21.

When the device works, the water supply head can be adjusted by controlling the height of the water supply tank 4 so as to meet the test conditions; the runoff mode of water can be controlled by controlling the control valves on the second pipeline, the third pipeline and the fourth pipeline, and the runoff mode is respectively used for simulating the conditions of diving runoff, confined water runoff and natural rainfall.

In the test process, when the water level descending process in the soil body 23 needs to be simulated, the piston 27 is pulled downwards to make the piston 27 be at the lower limit position, as shown in fig. 11 and 12, at this time, the first water leakage hole 261 on the seepage cylinder 26 is located between the first sealing ring 2711 and the second sealing ring 2712, that is, the blocking ring 271 blocks the first water leakage hole 261 on the seepage cylinder 26; the second water leakage hole 262 is located between the blocking ring 271 and the blocking plate 272. Thus, water flowing down from the diving simulation area does not enter the confined water simulation area 242 through the first water leakage holes 261 but enters the filtering area 243 through the second water leakage holes 262.

After the water level in the soil 23 is lowered to the set height, the piston 27 is pushed upward to make the piston 27 located at the upper limit position, as shown in fig. 13 and 14, at this time, the second water leakage hole 262 of the seepage cylinder 26 is located below the third sealing ring 2721, that is, the blocking plate 272 isolates the first water leakage hole 261 from the second water leakage hole 262 on the seepage cylinder 26. In this case, if the diving runoff or the natural rainfall is to be simulated, the water in the soil 23 will not enter the filtering area 243 through the second water leakage hole 262, and therefore, the simulation process will not be affected. If the confined water runoff is to be simulated, the water in the confined water simulation area 242 may reversely enter the soil 23 through the first water leakage holes 261, so as to simulate the confined water runoff. It can be seen that, in the simulation process, the filtering area 243 is an independent space, which does not affect the simulation process, and finally, the water in the filtering area 243 is filtered and returned to the circulation water tank 3.

Claims

1. The utility model provides a water level fluctuation arouses simulation device that overlay type karst sinks which characterized in that: the device comprises a simulation unit, wherein the inner space of a test box body of the simulation unit is divided into a diving simulation area, a confined water simulation area and a filtering area by a first partition plate and a second partition plate, a soil body is arranged in the diving simulation area, and a hole dissolving simulation hole is formed in the first partition plate;

there are two working positions in which the tool is,

2. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 1, wherein: a water outlet is formed in the bottom plate of the test box body, and a detachable filter box is arranged at the water outlet.

3. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 2, wherein: the bottom surface of the filter box is provided with filter holes, filter paper is laid in the filter box, the bottom surface of the test box body is provided with a connecting cylinder, and the connecting cylinder is inserted into the filter box and is in sealing connection with the filter box.

4. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 2, wherein: the bottom plate of the test box body is of a conical structure, the water outlet is arranged at the lowest point of the conical structure, and the upper side surface of the plugging plate is a spherical surface or a conical surface.

5. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 1, wherein: still include the body frame body, the analog unit set up in the body frame body on, the body frame body on slide and be provided with the water supply tank, the body frame body on be provided with and be used for driving gliding drive unit about the water supply tank, the water supply tank cut apart into water supply district and return water district by the overflow plate, water supply district in be provided with water inlet and delivery port, return water district in be provided with the return water mouth, the delivery port respectively through second pipeline and third pipeline with dive analog domain and pressure-bearing water analog domain be linked together.

6. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 5, wherein: the water supply tank comprises a tank body, the driving unit comprises a lead screw which is rotatably arranged on the main frame body, a water-resisting cylinder which is coaxially arranged with the lead screw is arranged in the tank body, the lower end of the water-resisting cylinder is fixedly connected with the closed end of the tank body in a sealing manner, the closed end of the tank body is provided with a through hole for accommodating the lead screw, and a screw matched with the lead screw is fixedly arranged in the water-resisting cylinder.

7. The apparatus for simulating the collapse of overburden type karst caused by water level fluctuation as claimed in claim 6, wherein: the main frame body on be located the both sides of water supply tank are provided with the guide arm respectively, the staving on fixedly be provided with guide holder that the guide arm matched with, the main frame body on be provided with driving motor, just driving motor's power output shaft pass through drive mechanism with the lead screw link to each other.

8. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 5, wherein: the diving simulation area in be provided with the third baffle, just the third baffle will diving simulation area divide into water distribution area and test area, the third baffle on be provided with the water distribution hole, the soil body set up in the test area in, the delivery port of water supply tank pass through the second pipeline with the water distribution area be linked together.

9. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 8, wherein: and a spray pipe assembly used for simulating natural rainfall is arranged above the test area in the test box body.

10. The simulation device for simulating the collapse of the overburden type karst caused by the water level fluctuation according to claim 1, wherein: the test box body adopt transparent material to make and form, bury the haulage rope underground in the top layer of soil body, just the projection of haulage rope in the horizontal plane pass through dissolve the centre of a circle in hole simulation hole, the haulage rope on evenly be provided with a plurality of pointer, and the upper end of pointer exposes in the outside of soil body, the test box body on be provided with the scale that is used for instructing vertical dimension and horizontal dimension.