阅读说明：本技术 一种模拟地下空间开发致灾的物理试验系统及方法 (Physical test system and method for simulating underground space development disaster ) 是由 廖云平 余瞻 吴斌 陈立川 钟明洋 董平 胡昌恒 田明 于 2021-06-18 设计创作，主要内容包括：本发明地质灾害致灾机理与防治技术领域,尤其涉及模拟地下空间开发致灾的物理试验系统。包括安装架,还包括设置于安装架上方的上部试验箱、设置于安装架下部的供排水循环系统,设置于上部试验箱内部的检测控制单元和模拟自然气候变化的气候模拟单元；所述上部试验箱包括用于装水的外部试验箱和用于装土体的内部试验箱,所述外部试验箱顶部敞开,且在底面中部设有第一通孔,所述内部试验箱的上端敞开,且在其底部开设有第二通孔；本技术方案可以对受集群效应作用而发生岩溶土洞集体塌陷的诱发因素、土洞演化和坍塌过程进行模拟研究。(The invention relates to the technical field of geological disaster causing mechanism and prevention and control, in particular to a physical test system for simulating underground space development disaster causing. The device comprises a mounting rack, an upper test box arranged above the mounting rack, a water supply and drainage circulating system arranged at the lower part of the mounting rack, a detection control unit arranged in the upper test box and a climate simulation unit for simulating natural climate change; the upper test box comprises an external test box for containing water and an internal test box for containing a soil body, the top of the external test box is open, a first through hole is formed in the middle of the bottom surface of the external test box, the upper end of the internal test box is open, and a second through hole is formed in the bottom of the internal test box; the technical scheme can simulate and research the induction factors of karst soil cave collective collapse, soil cave evolution and collapse process under the action of the clustering effect.)

1. A physical test system for simulating underground space development disaster comprises a mounting rack, and is characterized by also comprising an upper test box arranged above the mounting rack, a water supply and drainage circulating system arranged at the lower part of the mounting rack, a detection control unit arranged in the upper test box, and a climate simulation unit for simulating natural climate change;

the upper test box comprises an external test box for containing water and an internal test box for containing a soil body, the top of the external test box is open, a first through hole is formed in the middle of the bottom surface of the external test box, the internal test boxes are arranged in the external test box, the upper ends of the internal test boxes are open, and a second through hole is formed in the bottom of the internal test box;

the water supply and drainage circulating system comprises a water tank, a water pump, a first connecting pipe and a first gate valve, wherein the water pump pumps water in the water tank to an external test box through the connecting pipe;

the second through holes of the plurality of internal test boxes are respectively communicated with the first precipitation chamber through second connecting pipes, second gate valves for controlling the water flow of the connecting pipes are arranged on the second connecting pipes, karst cavities connected with the second connecting pipes in series are arranged on the second connecting pipes, and the karst cavities are used for collecting soil bodies discharged from the internal test boxes;

the test method is as follows:

step 1, collecting a covering layer soil sample required by a test, measuring natural density and natural water content, taking the soil sample, performing a direct shear test, and measuring an internal friction angle and cohesive force;

step 2, the soil sample collected in the step 1 is sent to a laboratory to be dried and crushed for standby;

step 3, mixing silt and the dried soil sample according to the natural density and the natural water content determined in the step 1 in proportion to prepare a covering layer soil body required by the test;

step 4, paving the soil sample prepared in the step 3 in an internal test box in layers, wherein the thickness of a soil layer paved each time is 2cm and compacting, the total thickness of the soil layer is determined according to the test purpose, and an optical fiber sensor and a pore fluid osmometer are paved in three layers;

step 5, closing a gate valve of a second connecting pipe, injecting water into the external test box through a variable-frequency water pump and a water level controller, slowly permeating the injected water into a covered soil layer of the test from micropores of the internal test box, opening the gate valve after the soil layer reaches a certain saturation degree, and discharging the water into a water tank through the second connecting pipe;

step 6, repeating the step 5 until the tested covering soil layer is completely saturated;

step 7, starting an air dryer, and air-drying the tested covering soil layer to solidify the soil layer;

8, repeating the step 5 to the step 6, simulating a soil layer consolidation process, and forming a soil hole at the bottom;

step 9, calculating the daily rainfall of the simulation area according to the purpose of the test, starting to implement the rainfall process, starting each monitoring device and video monitoring, making the rainfall reach the water level required by the test, starting a gate valve of a second connecting pipe, discharging water in a soil layer, and collecting the soil layer;

step 10, repeating the step 9 until the soil layer collapses;

and 11, collecting and analyzing collapse test process data of the karst collapse group, and establishing a water-soil-gas functional relation.

2. The physical test system for simulating underground space development disaster according to claim 1, wherein the detection control unit comprises a monitoring unit, a control unit and a video system, the monitoring unit comprises an optical fiber sensor for monitoring soil deformation, a pore fluid osmometer for pressure in pores of soil, and a water pressure monitor for monitoring water pressure in karst cavities, the control unit comprises a computer terminal software, a timer, a water level monitor and a rain gauge, the computer terminal software is in signal connection with the monitoring unit, the timer is used for controlling rainfall and sunshine time, the water level monitor is used for testing water level control, the rain gauge is used for controlling single rainfall, the video system comprises a high definition camera for shooting test process and result, and the video system provides karst ground collapse group occurrence, And reproducing the video in the whole process of development and collapse.

3. The physical test system for simulating underground space development disaster according to claim 1, wherein the climate simulation unit comprises a pressure water rain device and an air dryer, the water inlet end of the pressure water rain device is connected with the water outlet end of a water pump in the water supply and drainage system, and the other end of the pressure water rain device is positioned right above the upper test box.

4. The physical test system for simulating underground space development disaster according to claim 1, wherein the bottom of the karst cavity is tapered, and the upper part of the karst cavity is connected in series with the second connecting pipe.

5. The physical test system for simulating underground space development disaster according to claim 1, wherein the partition boards between the first and second settling chambers, the second and third settling chambers, and the third and fourth settling chambers are all provided with filter layers, and the filter layers cover the permeable holes on the partition boards.

6. The physical test system for simulating underground space development disaster according to claim 1, wherein the external test chamber, the internal test chamber, the water tank and the karst cavity are made of transparent materials.

7. The physical test system for simulating the development hazard in an underground space according to claim 1, wherein the outer test chamber and the inner test chamber are both cylindrical in shape, and a plurality of the inner test chambers are arranged tangentially to the inner wall of the outer test chamber.

Technical Field

The invention belongs to the technical field of geological disaster causing mechanism and prevention and control, and particularly relates to a physical test system and method for simulating underground space development disaster causing.

Background

The development and use of underground space, for example tunnel etc. can cause often that geological gap seeps water, and the process of infiltration can drive soil particle flow to produce ground and cave in, ground cave in is a typical geological disaster, has strong disguise, difficult predictability and the characteristics of process complicacy, often the emergence of piece is formed to the crowd, and the cluster effect is obvious. So far, the collapse cause mechanism exceeds 10, such as 'vacuum absorption theory' proposed by xu Wei nation, gravity collapse, submerged collapse, burst collapse and 'three-machine theory' proposed by Roche, etc. under the guidance of these theories, the prediction and prevention of ground collapse in China are greatly advanced, but the disaster-causing induction factors are complex and changeable, the prevention and treatment measures are single, some collapse points are recurred after being treated for many times, and not only the ground collapse is not radically treated, but also a lot of manpower and material resources are consumed. The reason is that natural conditions are extremely complex and changeable, the nature of collapse and disaster is the process of multi-factor comprehensive linkage, the existing ground collapse mechanism or cause research is mostly limited to the phenomenon reasoning under ideal conditions or the research is carried out aiming at a certain point, and systematic research on the induction factors of the collective collapse of the soil caverns under the action of the cluster effect, the soil cavern evolution and the collapse process is insufficient; on the other hand, the method is limited to the current technical development level, it is difficult to comprehensively research geological disasters by using high-precision equipment like medical diagnosis, such as a CT scanning technology and a nuclear magnetic resonance technology, and even if relatively advanced technical means such as a geological radar, a high-density electrical method and a shallow seismic wave reflection method are used, accurate judgment and effective prevention and control on the essence of the ground collapse group are difficult to make due to the multi-solution nature of geophysical interpretation.

Disclosure of Invention

Aiming at the defects of the technology, the invention aims to provide a physical test system and a method for simulating underground space development disaster, so as to research the inducement factor of collapse caused by the cluster effect, the evolution and collapse process of soil caves, and further make accurate judgment and effective prevention and treatment on ground collapse groups.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the physical test system for simulating underground space development disaster comprises a mounting rack, an upper test box arranged on the mounting rack, a water supply and drainage circulating system arranged at the lower part of the mounting rack, a detection control unit arranged in the upper test box and a climate simulation unit for simulating natural climate change;

the upper test box comprises an external test box for containing water and an internal test box for containing a soil body, the top of the external test box is open, a first through hole is formed in the middle of the bottom surface of the external test box, the internal test boxes are arranged in the external test box, the upper ends of the internal test boxes are open, second through holes are formed in the bottoms of the internal test boxes, micropores are formed in the outer wall of each internal test box and are round holes and/or strip-shaped holes which are distributed in a mixed mode so as to simulate soil layer pores and cracks, and the simulation effect on the external environment is further improved;

the water supply and drainage circulation system comprises a water tank, a water pump, a first connecting pipe and a first gate valve, the water pump pumps water in the water tank to an external test box through the connecting pipe, a partition board is arranged in the water tank and divides the water tank into four chambers, the four chambers are sequentially a first precipitation chamber, a second precipitation chamber, a third precipitation chamber and a fourth precipitation chamber, water permeable holes are formed in the partition board between the first precipitation chamber and the second precipitation chamber, the partition board between the second precipitation chamber and the third precipitation chamber and the upper parts of the partition boards between the third precipitation chamber and the fourth precipitation chamber, and the water pump is located in the fourth precipitation chamber;

the second through holes of the internal test chambers are communicated with the first precipitation chamber through second connecting pipes respectively, second gate valves for controlling the water flow of the connecting pipes are arranged on the second connecting pipes, karst cavities connected with the second connecting pipes in series are arranged on the second connecting pipes, and the karst cavities are used for collecting soil bodies discharged from the internal test chambers.

Further inject, it includes monitoring unit, the control unit and video system constitution to detect the control unit, the monitoring unit includes the optical fiber sensor who is used for the monitoring of soil body deformation, for the barometer of pressure pore fluid in the soil body pore, be used for the atmospheric pressure monitoring meter of atmospheric pressure monitoring in the karst cavity, the control unit includes computer terminal software, time-recorder, water level monitoring meter, rainfall gauge, computer terminal software and monitoring unit signal connection for physical data's collection, transmission, calculation and save, the time-recorder is used for rainfall and sunshine time control, the water level monitoring meter is used for experimental water level control, the rainfall gauge is used for the control of single rainfall. The video system consists of a high-definition camera and is used for shooting test processes and results and providing a reappearance video of the whole process of occurrence, development and collapse of the ground collapse group.

Further inject, the weather analog unit includes pressure ponding rainfall ware and air dryer, the end of intaking of pressure ponding rainfall ware is connected with the water pump play water end among the confession drainage system, its other end of pressure ponding rainfall lies in directly over the upper portion test box, and its beneficial part lies in, according to the daily rainfall capacity of experimental requirement, control frequency conversion force (forcing) pump pressure, the simulation rainfall to and simulate the sunshine evaporation effect of arid climate through the air dryer, can simulate the influence that natural environment caused to the soil body sinks.

Further inject, the bottom of karst cavity is the toper, and the upper portion and the second connecting pipe of karst cavity concatenate, and its beneficial part lies in, through set up the karst cavity on the second connecting pipe, can collect the soil body that sinks in the internal test case alone, is convenient for measure the volume of the soil body that sinks, and the purpose that the bottom set up to the toper is in order to promote the collection effect to the soil body.

Further inject, all be equipped with the filter layer on the baffle between first sediment chamber and the second sediment chamber, the baffle of second sediment chamber and third sediment chamber and the baffle of third sediment chamber and fourth sediment chamber, the hole of permeating water on the baffle is all covered to the filter layer, and its beneficial effect lies in, when deposiing step by step, sets up the filter layer on the hole of permeating water and can further promote the filter effect to muddy water.

Further inject, external test case, internal test case, basin and karst cavity all adopt transparent material to make, and its beneficial part lies in, is convenient for observe the water level of external test case, the volume of the soil body that sinks in the soil body change, the quality of water in the basin in the internal test case and the karst cavity.

Further, the transparent material is glass, and the glass has the advantage of low cost.

Further inject, the shape of external test case and internal test case is cylindrical, and a plurality of the internal test case is tangent with the inner wall of external test case and arranges, and its beneficial part lies in, and cylindrical can reduce area of contact when the installation, has increased the area of intaking of internal test case promptly, promotes the infiltration effect of the soil body.

In summary, the operation method of the technical scheme is as follows:

step 1, collecting a covering layer soil sample required by a test, and measuring natural density and natural water content; taking a soil sample by using a cutting ring to perform a direct shear test, and measuring an internal friction angle and cohesive force;

step 2, the soil sample collected in the step 1 is sent to a laboratory to be dried and crushed for standby;

step 3, mixing silt and the dried soil sample according to the natural density and the natural water content determined in the step 1 in proportion to prepare a covering layer soil body required by the test;

and 4, paving the soil sample prepared in the step 3 in an internal test box in layers, wherein the thickness of a soil layer paved each time is 2cm and is compacted, the total thickness of the soil layer is determined according to the test purpose, and the optical fiber sensor and the pore fluid osmometer are paved in three layers.

And 5, closing the gate valve of the second connecting pipe, injecting water into the external test box through the variable-frequency water pump and the water level controller, slowly permeating the injected water into the tested covering soil layer from the micropores of the internal test box, opening the gate valve after the soil layer reaches a certain saturation degree, and discharging the water into the water tank through the second connecting pipe.

And 6, repeating the step 5 until the tested covering soil layer is completely saturated.

And 7, starting an air dryer, and air-drying the tested covering soil layer to solidify the soil layer.

And 8, repeating the step 5 to the step 6, simulating the soil layer consolidation process, and forming a soil hole at the bottom.

And 9, calculating the daily rainfall of the simulation area according to the test purpose, starting to implement the rainfall process, starting the water level sensor, the water-air pressure sensor, the optical fiber sensor, the pore fluid osmometer and video monitoring, when the rainfall reaches the test required water level, starting the gate valve of the second connecting pipe, discharging water in the soil layer, and collecting the soil layer.

And 10, repeating the step 9 until the soil layer collapses.

And 11, collecting and analyzing collapse test process data of the karst collapse group, establishing a water-soil-gas functional relation, deciphering an action mechanism of the collapse group induced by underground engineering activities, and providing a solution for preventing and controlling the karst ground collapse group.

The invention has the technical effects that:

(1) the method is characterized in that process simulation is carried out on multiple factors and multiple working conditions such as soil thickness and deformation of karst ground collapse groups, soil cave evolution and collapse, water gas pressure, rainfall and underground water level fluctuation, qualitative and quantitative combination is carried out to represent the cause mechanism of the karst ground collapse groups, and theoretical support is provided for system control of karst ground collapse. (2) The arrangement of the plurality of internal test boxes can simulate karst ground collapse groups and can be used for researching induction factors, soil cave evolution and collapse processes of karst soil cave collective collapse under the action of a cluster effect. (3) The water supply and drainage circulation system can recycle the water source used in the test.

Drawings

FIG. 1 is a front view of a physical testing apparatus in this embodiment;

FIG. 2 is a top view of an external test chamber and an internal test chamber in this embodiment;

FIG. 3 is a top view of the sink in this embodiment;

FIG. 4 is a schematic top view of a physical testing apparatus according to this embodiment;

fig. 5 is a schematic view of the connection between the karst cavity and the second connection pipe in this embodiment.

Wherein, mounting bracket 1, external test case 2, first through-hole 21, basin 3, first precipitation chamber 31, second precipitation chamber 32, third precipitation chamber 33, fourth precipitation chamber 34, pressure ponding rainfall ware 4, water pump 5, measuring pump 6, computer terminal 7, second connecting pipe 8, first connecting pipe 81, karst cavity 9, internal test case 10, second through-hole 101.

Detailed Description

The following is further detailed by way of specific embodiments:

as shown in fig. 1, fig. 2, fig. 3 and fig. 4, the physical test system for simulating underground space development disaster comprises a mounting frame 1, wherein the mounting frame 1 is formed by fixing stainless steel beams and longitudinal beams to each other, a support beam is further arranged at the upper end of the mounting frame 1, a placing space is formed at the upper part of the support beam, an upper test chamber is installed in the placing space, the upper test chamber mainly comprises an external test chamber 2 and an internal test chamber 10, the internal test chamber 10 is arranged inside the external test chamber 2, in the embodiment, the internal test chamber 10 and the external test chamber 2 are cylinders with a bottom cover and a hollow middle part, the internal test chamber 10 and the external test chamber 2 are both made of transparent glass, which is good for observation, the external test chamber 2 is used for containing water to simulate underground water level, and a first through hole 21 is formed in the bottom surface of the external test chamber 2, the purpose of first through-hole 21 is convenient for discharge the water in external test case 2, be equipped with a plurality of internal test case 10 in external test case 2's inside, be 3 in this implementation, the quantity of internal test case 10 can be selected according to actual conditions, such aim at, can satisfy the karst experimental research of multiple soil layer under same environment, second through-hole 101 has been seted up on single internal test case 10's the bottom surface, the effect of second through-hole 101 is the karst cave of simulation soil layer karst in-process, the outside of a plurality of internal test case 10 all places in external test case 2 with the medial surface tangent of external test case 2.

A water supply and drainage circulation system is arranged at the lower part of the mounting frame 1, the water supply and drainage circulation system comprises a water tank 3, a water pump 5, a first connecting pipe 81 and a first gate valve, the water tank 3 is cylindrical, a partition board is arranged in the water tank 3 and divides the internal space of the water tank 3 into four parts, a first precipitation chamber 31, a second precipitation chamber 32, a third precipitation chamber 33 and a fourth precipitation chamber 34 are respectively arranged at the upper parts of the partition boards of the first precipitation chamber 31, the second precipitation chamber 32, the third precipitation chamber 33 and the third precipitation chamber 34, the water pump 5 is positioned in the fourth precipitation chamber 34, the water pump 5 sends the water pump 5 in the water tank 3 to the inside of the external test box 2 through the first connecting pipe 81, and a plurality of micropores are arranged on the outer side surface of the internal test box 10, inside the millipore effect was the soil layer with infiltration to internal test case 10 in the external test case 2, the infiltration mode of simulation groundwater in the soil layer, and the water discharge in the external test case 2 is to the fourth precipitation chamber 34 of basin 3 in, the micropore on the 2 outer walls of external test case is mixed distribution's round hole and bar hole, and its useful part lies in, and the mixture in round hole and bar hole sets up can simulate soil layer hole and crack, further promotes the simulation effect to external environment. The water pump 5 is a variable frequency water pump in this embodiment. Inside test box 10's second through-hole 101 is in being convenient for deposit discharged water step by step through second connecting pipe 8 and first sediment chamber 31 intercommunication, and the purpose that sets up first sediment chamber 31, second sediment chamber 32, third sediment chamber 33 and fourth sediment chamber 34, preferably, in this embodiment, all is equipped with the filter layer on the baffle of seting up the hole of permeating water, and the filter layer can be the geotechnological cloth layer, can strengthen the filter effect of muddy water like this.

As shown in fig. 5, in order to collect respectively the coating that collapses in a plurality of internal test case 10, be convenient for subsequent weighing, all be equipped with karst cavity 9 on each second connecting pipe 8, karst cavity 9 concatenates on second connecting pipe 8, and the end of just intaking is located the upper end of karst cavity 9, it is located the upper portion of karst cavity 9 to go out the water end, such good play lies in, the supreme discharge gradually can be followed in karst cavity 9 to the muddy water of internal test case 10 exhaust, be convenient for collect the silt in the muddy water, be equipped with the branch pipe simultaneously in the bottom of karst cavity 9, be equipped with the gate valve on the branch pipe, be convenient for discharge the earth of collecting.

In order to simulate the natural environment and measure the physical constants received in the soil layer collapse process, the device further comprises a detection control unit and a climate simulation unit, the detection control unit comprises a monitoring unit, the control unit and a video system are formed, the monitoring unit comprises an optical fiber sensor used for monitoring the deformation of the soil body, a pore fluid osmometer used for monitoring the pore pressure of the soil body, a water and air pressure monitoring meter used for monitoring the water and air pressure in the karst cavity 9, the control unit comprises computer terminal 7 software, a timer, a water level monitoring meter and a rain gauge, the computer terminal 7 software is connected with the monitoring unit and used for collecting, transmitting, calculating and storing physical data, the timer is used for controlling rainfall and sunshine time, the water level monitoring meter is used for controlling the test water level, and the rain gauge is used for controlling the single rainfall. The video system consists of a high-definition camera and is used for shooting test processes and results and providing reproduction videos of karst ground collapse group occurrence, development and collapse whole processes.

The weather simulation unit comprises a pressure water accumulation rainfall device 4 and an air dryer, wherein the water inlet end of the pressure water accumulation rainfall device 4 is connected with the water outlet end of a water pump 5 in a water supply and drainage system, and the other end of the pressure water accumulation rainfall device is positioned right above an upper test box.

The gate valve used in the present apparatus may be a commercially available ordinary gate valve.

The physical test device operates as follows:

step 1, collecting a covering layer soil sample required by a test, and measuring natural density and natural water content; taking a soil sample by using a cutting ring to perform a direct shear test, and measuring an internal friction angle and cohesive force;

step 2, the soil sample collected in the step 1 is sent to a laboratory to be dried and crushed for standby;

step 3, mixing silt and the dried soil sample according to the natural density and the natural water content determined in the step 1 in proportion to prepare a covering layer soil body required by the test;

and 4, paving the soil sample prepared in the step 3 in an internal test box 10 in a layered manner, wherein the thickness of a soil layer paved each time is 2cm and the soil layer is compacted, the total thickness of the soil layer is determined according to the test purpose, and the optical fiber sensor and the pore fluid osmometer are paved in three layers.

And 5, closing the gate valve of the second connecting pipe 8, injecting water into the external test box 2 through the variable frequency water pump and the water level controller, slowly permeating the injected water into the tested covering soil layer from the micropores of the internal test box 10, opening the gate valve after the soil layer reaches a certain saturation degree, and discharging the water into the water tank 3 through the second connecting pipe 8.

And 6, repeating the step 5 until the tested covering soil layer is completely saturated.

And 7, starting an air dryer, and air-drying the tested covering soil layer to solidify the soil layer.

And 8, repeating the step 5 to the step 6, simulating the soil layer consolidation process, and forming a soil hole at the bottom.

And 9, calculating the daily rainfall of the simulation area according to the test purpose, starting to implement the rainfall process, starting the water level sensor, the water-air pressure sensor, the optical fiber sensor, the pore fluid osmometer and video monitoring, when the rainfall reaches the test required water level, starting the gate valve of the second connecting pipe 8, discharging water in the soil layer, and collecting the soil layer.

And 10, repeating the step 9 until the soil layer collapses.

And 11, collecting and analyzing collapse test process data of the karst collapse group, establishing a water-soil-gas functional relation, deciphering an action mechanism of the collapse group induced by underground engineering activities, and providing a solution for preventing and controlling the karst ground collapse group.

It should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," "fixed," and the like are used broadly in the present invention, and may be, for example, fixedly connected, detachably connected, or integrally connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.