阅读说明：本技术 一种可控制土洞形成过程的物理模拟实验装置及方法 (Physical simulation experiment device and method capable of controlling soil cave forming process ) 是由 贾龙 雷明堂 李录娟 蒙彦 蒋小珍 潘宗源 殷仁朝 戴建玲 管振德 吴远斌 周富 于 2019-12-04 设计创作，主要内容包括：本发明公开了一种可控制土洞形成过程的物理模拟实验装置及方法,所述实验装置主要包括土洞模拟箱、渗流模拟装置、重力模拟装置；实验过程中通过调节渗流模拟装置的供水塔的水头高度提供水渗流力,利用重力模拟装置的传输带的摩擦模拟自重应力,作用于土洞模拟箱中的岩土体,模拟有覆盖土的岩溶发育区,岩面以上的土体在自重应力、地下水渗流力因素影响下,遭到流失迁移至岩溶通道,而形成土中洞穴的过程。本试验装置结构简单,成本低廉,本实验方法操作方法简便,用土量少,适合多种条件组合下多次重复实验,并能实现单一变量对土洞形成变形规律的影响效应,对研究岩溶地面塌陷防治措施有着重要的理论及工程意义。(The invention discloses a physical simulation experiment device and a physical simulation experiment method capable of controlling a soil cave forming process, wherein the experiment device mainly comprises a soil cave simulation box, a seepage simulation device and a gravity simulation device; the water seepage force is provided by adjusting the height of a water head of a water supply tower of the seepage simulation device in the experimental process, the dead weight stress is simulated by using the friction of a transmission belt of the gravity simulation device, the dead weight stress acts on rock and soil bodies in the soil cave simulation box, a karst development area covering soil is simulated, and the soil body above the rock surface suffers loss and migrates to a karst channel under the influence of the dead weight stress and the factor of the groundwater seepage force, so that the process of cave in soil is formed. The test device is simple in structure and low in cost, the test method is simple and convenient to operate, the soil consumption is low, the test device is suitable for repeated experiments under various conditions, the effect of a single variable on the deformation rule of the soil cave can be realized, and the test device has important theoretical and engineering significance for researching karst ground collapse prevention and control measures.)

1. A physical simulation experiment device capable of controlling a soil cave forming process is characterized by comprising a seepage simulation device (1), a gravity simulation device (2) and a soil cave simulation box (3);

the seepage simulation device (1) mainly comprises a water supply tower (11), a water drainage port (13) communicated with a conduit (12) led out from the bottom of the water supply tower (11), a height adjusting device (14) used for adjusting the height of the water drainage port (13), a water guide pipe (15) led out from the bottom of the water supply tower (11), a seepage valve (16) arranged on the water guide pipe (15) and an observation pipe (17) vertically arranged on the water guide pipe (15);

the water supply tower (11) is fixed, and the bottom of the water supply tower (11) is connected with a tap water pipe through a water inlet valve (18);

the gravity simulation device (2) comprises an experiment table (21), rollers (22) positioned at two ends of the experiment table (21), a transmission belt (23) which bypasses the rollers (22) and forms a linkage with the rollers (22), a driving motor (24) used for providing driving force for the rollers (22) and a driving motor adjusting switch used for adjusting the power of the driving motor (24) so as to further control the moving speed of the transmission belt (23); a jack (25) for adjusting the inclination angle of the experiment table (21) is arranged at the rear end of the experiment table (21);

soil cave analog box (3) are the rectangular bodily form, and transparent plate (31) can be dismantled at the top, and baffle (32) can be dismantled to the front end, baffle export (33) have been seted up on baffle (32), and soil cave analog box (3) rear end is connected aqueduct (15) of seepage flow analog device (1), soil cave analog box (3) rear end is fixed through fixed rope, the bottom of soil cave analog box (3) is passed in transmission band (23) of gravity analog device (2).

2. A physical simulation experiment apparatus capable of controlling a soil cave forming process according to claim 1, wherein the guide pipe (12) is a hose, and the elevation and the lowering of the guide pipe (12) can be controlled by the height adjusting means (14).

3. The physical simulation experiment apparatus capable of controlling a soil cave forming process according to claim 1, wherein the driving motor (24) is installed in the experiment table (21) and located in a space surrounded by the roller (22) and the conveyor belt (23).

4. The physical simulation experiment apparatus capable of controlling a soil cave forming process according to claim 1, wherein the water guide pipe (15) is connected with the rear end of the soil cave simulating tank (3) through a plurality of branch pipes (151).

5. The physical simulation experiment device capable of controlling the soil cave forming process according to claim 1, wherein a tension meter (34) for recording the stress condition of the simulation box is arranged on the fixing rope at the rear end of the soil cave simulation box (3).

6. The physical simulation experiment device capable of controlling the soil cave forming process according to claim 1, wherein the soil cave simulating box (3) is in a regular quadrangular prism shape, and the bottom side length is 1.5 m.

7. A physical simulation experiment apparatus capable of controlling a soil cave forming process according to claim 1, wherein the detachable transparent plate (31) is made of transparent acrylic plate.

8. A physical simulation experiment method for a soil cave forming process by using the device of any one of claims 1 to 7, which is characterized by mainly comprising the following steps:

s1, adjusting the inclination angle of the experiment table (21) through a jack (25), closing a baffle plate outlet (33) of the soil cave simulation box (3), and smearing vaseline at the contact part of a baffle plate (32) and a conveying belt (23); filling soil in the soil cave simulation box (3) layer by layer according to an experimental scheme; stopping after moving for a certain distance by using a conveying belt (23) of the gravity simulation device (2), simulating the state of a soil layer under natural gravity, and then opening an outlet of a baffle;

s2, simulating the coupling of a seepage field and a gravity field in the soil cave forming process; the method is divided into two methods according to different coupling modes, wherein one method is a seepage-gravity sequential coupling method, and the other method is a seepage-gravity complete coupling method;

s21, the seepage-gravity sequential coupling method specifically comprises the following steps: the method is realized by performing multiple cycles of single seepage field analysis and single gravity field analysis in sequence, namely:

s211, simulating a gravity field: firstly, starting a driving motor (24) to drive a transmission belt (23) to move, and firstly simulating the state of a soil layer under gravity by using a gravity simulation device (2) and then stopping friction;

s212, simulating a seepage process: then adjusting the height of the fixed water outlet (13), opening a seepage valve (16), starting water inlet of the soil cave simulation box (3), simulating a seepage process, and closing the seepage valve (16) after the soil body is saturated with water or has certain change;

s213, circulating the operations of S21 and S22;

s22, the seepage-gravity complete coupling method specifically comprises the following steps: the interaction of the seepage field and the gravitational field is considered simultaneously in a single analysis, namely:

and meanwhile, a seepage valve (16) and a driving motor (24) are opened, a conveying belt (23) moves while seepage water enters the soil cave simulation box (3), the seepage field and the gravity field act together to observe the change rule of the soil body, and the conveying belt can be stopped and a water inlet switch can be closed at any time in the observation process.

9. Method according to claim 8, characterized in that the inclination of the laboratory table (21) is adjusted in the range of 0-45 °.

10. Method according to claim 8, characterized in that different transport belts (23) are exchangeable so that the friction coefficient is adjustable.

Technical Field

The invention relates to the technical field of rock-soil indoor physical simulation experiments, in particular to a physical simulation experiment device and method capable of controlling a soil cave forming process.

Background

The soil cave is a cave in soil formed by loss and migration of soil above a rock surface in a karst development area with covering soil under the influence of factors such as dead weight stress, groundwater seepage force and the like. It forms a soil layer which is easy to be submerged and has a karst channel for draining and storing the submerged and corroded substances. The soil cave is a hidden unfavorable geological phenomenon of karst, and after the cave is continuously expanded towards the ground, a top plate is unstable to collapse or cause deformation and subsidence of the ground, so that geological disasters or engineering accidents can be formed finally. A large number of engineering practices prove that the process of forming and developing the soil cavern is the early stage or inoculation stage of karst ground collapse, and is the key stage of monitoring and early warning of karst ground collapse. Therefore, the discussion of the soil cave development rule has important theoretical and engineering significance for researching the karst collapse prevention and control measures.

The process and the rule of ground deformation caused by the soil cavern can be simulated through an indoor model test, and meanwhile, the indoor model test is also one of methods for verifying whether theoretical analysis and numerical simulation of the soil cavern forming process are reasonable. In the past, a physical model for researching ground deformation can only observe a ground surface deformation result, and can not capture the process of soil hole development and evolution inside a soil layer in real time when self-weight stress and seepage force act on the soil body.

Disclosure of Invention

Aiming at the existing problems, the invention provides a physical simulation experiment device and a physical simulation experiment method capable of controlling the soil cave forming process.

The technical scheme of the invention is as follows:

a physical simulation experiment device capable of controlling a soil cave forming process comprises a seepage simulation device, a gravity simulation device and a soil cave simulation box;

the seepage simulation device mainly comprises a water supply tower, a water outlet communicated with a conduit led out from the bottom of the water supply tower, a height adjusting device for adjusting the height of the water outlet, a water guide pipe led out from the bottom of the water supply tower, a seepage valve arranged on the water guide pipe and an observation pipe vertically arranged on the water guide pipe;

the height adjusting device specifically comprises a pulley and a stretching device which bypasses the pulley, one stretching end is fixed at the upper end of the conduit, the other stretching end is a free end, and the free end of the pull rope is pulled to drive the conduit to ascend or descend, so that the height of the water discharge opening 13 is controlled, and the water head height h is further controlled.

The water supply tower is fixed, and the bottom of the water supply tower is connected with a tap water pipe through a water inlet valve;

opening a water inlet valve, injecting tap water into the water supply tower to enable the water level in the water supply tower to rise, simulating water level change by adjusting the height and the water inlet amount of a water outlet, and reading the water pressure in an observation pipe after maintaining the constant seepage water pressure;

the gravity simulation device comprises an experiment table, rollers positioned at two ends of the experiment table, a transmission belt which bypasses the rollers and forms a linkage device with the rollers, a driving motor used for providing driving force for the rollers and a driving motor adjusting switch used for adjusting the power of the driving motor so as to further control the moving speed of the transmission belt; a jack for adjusting the inclination angle of the experiment table is arranged at the rear end of the experiment table;

soil hole simulation case is the rectangular bodily form, and the top is for dismantling the transparent plate, and the front end is for dismantling the baffle, the baffle export has been seted up on the baffle, can change the size and the position of baffle export according to the experiment needs, and soil hole simulation case rear end is connected seepage flow analogue means's aqueduct, it is fixed that soil hole simulation case rear end passes through fixed rope, gravity analogue means's transmission band passes soil hole simulation case's bottom. When the soil body in the soil cave simulation box moves along with the conveying belt due to seepage or dead weight, the baffle prevents the movement. The outlet of the baffle is used for simulating a karst passage for transporting the underetched objects in the soil cave.

Further, in the above aspect, the duct is a hose, and the raising and lowering of the duct can be controlled by the height adjusting device.

Further, in the above scheme, the driving motor is installed in the experiment table and located in a space surrounded by the roller and the conveyor belt.

Further, in the above scheme, the water guide pipe is connected with the rear end of the soil cave simulation box through a plurality of branch pipes. The device is used for decentralized water supply, and can simulate the seepage process more accurately.

Further, in the above scheme, a tension meter for recording the stress condition of the simulation box is arranged on the fixed rope at the rear end of the soil cave simulation box.

Further, in the scheme, the soil cave simulation box is in a regular quadrangular prism shape, and the length of the bottom edge is 1.5 m.

Further, in the above scheme, the detachable transparent plate is made of a transparent acrylic plate. The box is convenient to fill soil after being disassembled, and soil change is convenient to observe during the test in installation.

Furthermore, a water tank is arranged below the experiment table on the front side of the soil cave simulation box and used for collecting water and soil flowing out of the soil cave simulation box.

The invention may also include other ancillary equipment such as video recording equipment such as cameras which may be used to record the simulated hole formation process.

A physical simulation experiment method for controlling a soil cave forming process mainly comprises the following steps:

s1, adjusting the inclination angle of the experiment table through a jack, closing a baffle outlet of the soil cave simulation box, and coating vaseline at the contact position of the baffle and the transmission belt to play a certain sealing role; filling soil in a soil cave simulation box layer by layer according to an experimental scheme; stopping after moving for a certain distance by using a conveying belt of the gravity simulation device, simulating the state of a soil layer under natural gravity, and then opening an outlet of a baffle;

s2, simulating the coupling of a seepage field and a gravity field in the soil cave forming process; the method is divided into two methods according to different coupling modes, wherein one method is a seepage-gravity sequential coupling method, and the other method is a seepage-gravity complete coupling method;

s21, the seepage-gravity sequential coupling method specifically comprises the following steps: the method is realized by performing multiple cycles of single seepage field analysis and single gravity field analysis in sequence, namely:

s211, simulating a gravity field: firstly, starting a driving motor to drive a transmission belt to move, and utilizing a gravity simulation device to simulate the state of a soil layer under gravity and then stopping friction;

s212, simulating a seepage process: then adjusting the height of the fixed water outlet, opening a seepage valve, starting water inlet of the soil cave simulation box, simulating a seepage process, and closing the seepage valve after the soil body is saturated with water or has certain change;

s213, circulating the operations of S21 and S22;

s22, the seepage-gravity complete coupling method specifically comprises the following steps: the interaction of the seepage field and the gravitational field is considered simultaneously in a single analysis, namely:

and meanwhile, a seepage valve and a driving motor are opened, the transmission belt moves while seepage water flows into the soil cave simulation box, the seepage field and the gravity field jointly act to observe the change rule of the soil body, and the transmission belt can be stopped and the water inlet switch can be closed at any time in the observation process.

Further, the inclination angle adjusting range of the experiment table is 0-45 degrees.

Further, different transmission belts can be replaced to adjust the friction coefficient.

The beneficial effects of the invention are shown in the following aspects:

firstly, the test device has the advantages of simple structure, low cost, simple and convenient operation method, small soil consumption and suitability for repeated experiments under various condition combinations so as to obtain the soil cave development rule.

Secondly, the motion of the conveyor belt can be controlled at will, namely, the friction force can appear or disappear at any time, and the whole damage process of the model can be directly and continuously observed.

Thirdly, the device simulates the change of the water level of underground water by utilizing the change of the water head height h of the water supply tower, and simulates the self-weight stress of the rock-soil body by utilizing the friction force of the transmission belt and the soil body, thereby realizing the simulation of seepage and gravity coupling and controlling the influence factors.

Fourthly, the number and the size of the gaps of the baffle plates of the simulation box can be adjusted, the inclination angle of the experiment table is changed, the friction coefficient of the transmission belt is adjusted, the water head height is adjusted, and the like, so that the evolution law of the soil cavern under different conditions is simulated, and the influence effect of a single variable on the deformation law of the soil cavern is realized.

Fifth, the method can be used as a method for verifying whether the theoretical analysis and the numerical simulation of soil cave formation are reasonable, and has important theoretical and engineering significance for researching the prevention and treatment measures of karst ground collapse.

Drawings

FIG. 1 is a schematic view of the overall structure of an experimental apparatus according to the present invention;

FIG. 2 is a schematic top view of the soil cave simulation box and test bed of the present invention;

FIG. 3 is a schematic front view of a soil cave simulation box and test bed of the present invention;

the device comprises a seepage simulation device 1, a water supply tower 11, a guide pipe 12, a water discharge opening 13, a height adjusting device 14, a pulley 141, a pulley 142, a pull rope 15, a water guide pipe 16, a seepage valve 17, an observation pipe 18, a water inlet valve 2, a gravity simulation device 21, a test bench 22, a roller 22, a conveyor belt 23, a driving motor 24, a jack 25, a soil cave simulation box 3, a detachable transparent plate 31, a baffle 32, a baffle outlet 33, a tension meter 34 and a water tank 4.

Detailed Description

The invention is described in further detail below with reference to the following figures and specific embodiments: