A karst area subway anti-floating simulation device and anti-floating water level simulation method

Abstract

The invention discloses a karst area subway anti-floating simulation device and an anti-floating water level simulation method thereof, comprising a constant water head supply box, a main body simulation box, and a constant water head discharge box, wherein the constant water head supply box and the constant water head discharge box are both connected with the main body simulation box through a pipeline; a karst simulation pipeline, a subway station simulation box body, and a geological condition simulation box are arranged in the main body simulation box; the method comprises the following steps: S1, allowing water to flow out from a supply outlet; S2, opening a second control valve and a third control valve to allow water to enter the karst simulation pipeline, a first electromagnetic flowmeter to monitor flow changes, and a flat mold pressure transmitter to monitor pressure signals; S3, after the water flow in the constant water head discharge box is stable, monitoring data changes; S4, the water flow is naturally drained, and monitoring data changes; S5, changing the parameters of the karst simulation pipeline and the geological condition simulation box, repeating steps S1 to S4, and obtaining comparative experimental data; S6, drawing a relationship line between water flow and subway anti-floating water level through the collected data.

Description

Technical Field

[0001] The invention relates to the field of geotechnical engineering, and in particular to a karst area subway anti-floating simulation device and an anti-floating water level simulation method thereof. Background Art

[0002] In recent years, the greenhouse effect has led to global warming, and the groundwater level has risen due to the structure and lithology of the groundwater aquifer, threatening the structural safety of underground buildings. Therefore, the study of the buoyancy of underground structures has become an extremely critical topic in urban geotechnical engineering, which involves not only the changing trend of groundwater levels in the medium- and long-term development of cities, but also the transmission mechanism and distribution law of pore water pressure in soil layers with different groundwater storage forms, the buoyancy value of underground structures in different soil layers, the buoyancy value when multiple layers of groundwater act, and the development of reasonable engineering anti-buoyancy measures.

[0003] With the continuous expansion of the scale of urban underground rail transit construction, most subway stations are mainly constructed with shallow burial and open excavation. However, the shallow groundwater level in the city is relatively high, and it generally shows an unstable trend. Subway safety plays a pivotal role in urban safety, so the anti-floating design of subway stations is a key link. The karst area has its own special geological environment. Subway construction is often accompanied by natural phenomena such as caves and underground rivers. The exploration of the anti-floating relationship of subway stations in karst areas must rely on corresponding simulation devices. Therefore, the design of a reasonable underground anti-floating simulation device provides data support for anti-floating measures in karst areas, which has become a hot issue in the research of subway anti-floating design.

[0004] The study found that the current subway anti-floating simulation devices have the following shortcomings: (1) From a functional point of view, most of the existing simulation devices are one-sidedly targeted at the aeration zone or aquifer under general conditions, lacking an organic combination of simulation functions of underground rivers and caves, and thus lacking the underground anti-floating simulation function in karst areas; (2) The existing simulation devices cannot easily change the simulated geological conditions, and the simulation accuracy of complex geological environments is not high; (3) The existing constant water head device design has large water fluctuations and instability, which has a great impact on subsequent data.

[0005] These shortcomings have seriously affected the underground anti-floating design during the construction of subways in karst areas. Faced with the complex hydrogeological conditions of underground river systems, underground anti-floating simulation in karst areas has become an important direction of scientific research for scientists. Summary of the invention

[0006] The purpose of the present invention is to provide a karst area subway anti-floating simulation device and an anti-floating water level simulation method thereof, which can monitor the dynamic changes of the anti-floating water level of the simulation body and the groundwater flow.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] A karst area subway anti-floating simulation device comprises a constant water head supply box, a main body simulation box, and a constant water head discharge box, wherein the constant water head supply box and the constant water head discharge box are both connected to the main body simulation box through a pipeline; a partition plate with a height lower than the side wall of the constant water head supply box is arranged in the constant water head supply box, and the constant water head supply box is provided with a replenishment water outlet and a replenishment water outlet, wherein the replenishment water outlet is located on one side of the partition plate, and the replenishment water outlet is located on the other side of the partition plate, and the replenishment water outlet is connected to the main body simulation box through a pipeline; the main body simulation box is made of organic glass, and a first water inlet, a second water inlet, a first water outlet, and a second water outlet are arranged on the main body simulation box, and the first water inlet is connected to the replenishment water outlet through a pipeline The second drain outlet is connected with the fixed water head discharge box through a pipeline, a karst simulation pipeline, a subway station simulation box and a geological condition simulation box are arranged in the main simulation box, both ends of the karst simulation pipeline are respectively connected with the first water inlet and the second drain outlet, a plurality of first simulation holes are arranged on the upper part of the karst simulation pipeline, a plurality of second simulation holes are arranged on the lower part of the karst simulation pipeline, and the hole spacing of the first simulation holes is greater than the hole spacing of the second simulation holes; a test port is arranged on the subway station simulation box and a flat mold pressure transmitter is connected through the test port; there are a plurality of geological condition simulation boxes, a plurality of third simulation holes are arranged on the geological condition simulation box, and the geological condition simulation box is filled with acrylic beads.

[0009] Furthermore, a first electromagnetic flowmeter is arranged on the pipe between the replenishing water outlet and the first water inlet, and two ends of the first electromagnetic flowmeter are respectively connected to the replenishing water outlet and the first water inlet pipes; a second electromagnetic flowmeter is arranged on the pipe between the second drain outlet and the constant water head discharge box, and two ends of the second electromagnetic flowmeter are respectively connected to the second drain outlet and the constant water head discharge box pipes.

[0010] Furthermore, a first control valve is provided on the pipeline between the first electromagnetic flowmeter and the first water inlet, a second control valve is provided on the pipeline between the second drain outlet and the second electromagnetic flowmeter, and a third control valve is provided on the pipeline between the second electromagnetic flowmeter and the fixed water discharge box.

[0011] Furthermore, a test port is provided at the center position of each side of the subway station simulation box, and the test port is threadedly connected to the flat die pressure transmitter. The model of the flat die pressure transmitter is CGYL-204, and the flat die pressure transmitter is connected to the analog signal acquisition system line.

[0012] Furthermore, the first water inlet and the second water inlet are both arranged on the left side of the main simulation box, the first drain outlet is arranged on the rear side of the main simulation box, and the second drain outlet is arranged on the right side of the main simulation box.

[0013] Furthermore, the internal length of the constant water head supply box is 0.4m, the internal width is 0.4m, the internal height is 0.4m, and the height of the partition is 0.3m; the internal length of the main simulation box is 1.5m, the internal width is 0.5m, and the internal height is 0.4m; the internal length of the subway station simulation box is 48cm, the internal width is 13cm, and the internal height is 18cm.

[0014] Furthermore, the outer diameter of the karst simulation pipe is 3.5 cm, the hole diameter of the first simulation hole is 3 mm, and the distance between adjacent holes is 3 mm; the hole diameter of the second simulation hole is 3 mm, and the distance between adjacent holes is 6 mm.

[0015] Furthermore, the internal length of the geological condition simulation box is 79 cm, the internal width is 14 cm, and the internal height is 19.5 cm; the diameter of the third simulation hole is 2 mm, and the distance between adjacent holes is 2 mm.

[0016] An anti-floating water level simulation method comprises the following steps:

[0017] S1, close the first control valve, open the water source, and the water flows into the constant water head supply box from the side close to the replenishment outlet. After the water overflows the partition, open the first control valve and the water flows out from the replenishment outlet;

[0018] S2, opening the second control valve and the third control valve to allow water to flow into the karst simulation pipeline in the main simulation box, monitoring the flow change through the first electromagnetic flowmeter, and monitoring the pressure signal through the flat die pressure transmitter, and the pressure signal data is collected by the analog signal acquisition system;

[0019] S3. After the water flow in the constant head discharge box is stable, the placement height of the constant head supply box is adjusted according to the test simulation requirements to simulate the data changes of different water inflows;

[0020] S4, the fixed head supply tank stops supplying water, allowing the water to drain naturally, simulating the data changes after the water flow ends;

[0021] S5. According to different karst geological conditions, the parameters of the karst simulation pipeline and the geological condition simulation box are changed, acrylic beads of different particle sizes are used to fill the geological condition simulation box, and steps S1 to S4 are repeated to obtain comparative experimental data;

[0022] S6. Arrange the data collected by the analog signal acquisition system and the first electromagnetic flowmeter and the second electromagnetic flowmeter, and draw a relationship line between the upstream water flow in the karst area and the subway anti-floating water level.

[0023] Compared with the prior art, the present invention has the following advantages and positive effects:

[0024] 1. The present invention uses organic glass to make the main simulation box design to visualize the simulation process, which is convenient for understanding and observing the state of water movement under different geological conditions. Compared with traditional simulation equipment, the present invention can comprehensively and clearly observe the process of the impact of underground water in the karst area on the subway station.

[0025] 2. The present invention monitors the simulation process through components such as flat die pressure transmitters and electromagnetic flow meters. Compared with traditional manual measurement and recording methods, this monitoring method can more accurately obtain data such as water level and flow. The numerical records are easy to collect, and the response relationship between the anti-floating water level and flow of subway stations in different karst water-containing media can be analyzed.

[0026] 3. The present invention can change and control various parameters of the constant head replenishment water tank and the geological condition simulation box. According to the actual needs of the simulation experiment, the present invention can carry out comparative experimental analysis and research under specific conditions for the complex hydrogeological conditions in the karst area. It has flexible simulation applicability, thus making the experimental data more convincing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 This is a cross-sectional structural diagram of the main simulation box;

[0030] Figure 3 This is a top view of the structure of the constant head supply tank;

[0031] Figure 4 for Figure 3 AA section view;

[0032] Figure 5 This is a top view of the structure of the karst simulation pipeline;

[0033] Figure 6 for Figure 5 BB cross-sectional view;

[0034] Figure 7 This is a cross-sectional structural diagram of the simulated box for the subway station;

[0035] Figure 8 This is a cross-sectional structural diagram of the geological condition simulation box. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work, any modifications, equivalent substitutions, improvements, etc., should be included in the protection scope of the present invention.

[0037] like Figure 1 As shown, the present invention provides a karst area subway anti-floating simulation device, including a constant water head supply box 1, a first electromagnetic flowmeter 2, a geological condition simulation box 3, a subway station simulation box 4, a simulation signal acquisition system 5, a main simulation box 6, a karst simulation pipeline 7, a second electromagnetic flowmeter 8, a constant water head discharge box 9, a first control valve 10, a second control valve 11, and a third control valve 12.

[0038] like Figure 3 , Figure 4 As shown, the constant head supply box 1 and the constant head discharge box 9 in the device both adopt a constant head water tank design. The overall inner diameter of the constant head supply box 1 is a 0.4m*0.4m*0.4m cube, without a top cover, and a 0.3m high partition 104 is arranged inside. The box body is provided with three M20*1.5 threaded ports to fix the upstream and downstream head difference. The threaded ports are respectively a replenishment water outlet 103 and two replenishment drainage outlets 101 and 102. The two replenishment drainage outlets 101 and 102 are both located on one side of the partition 104, and the replenishment water outlet 103 is located on the other side of the partition 104. The replenishment water outlet 103 is connected to the main simulation box 6 through a pipe. The replenishment water inlet is designed as the overall water source and is connected to a water pipe. Specifically, the water pipe is directly placed into the side of the large chamber of the box body without a separately designed outlet. The replenishment water outlet 103 is connected to the main simulation box body and serves as a connection port for the water supply of the device. It is designed as an M20*1.5 threaded port. The replenishment water outlets 101 and 102 are used to discharge excess water when the water head reaches the baffle to achieve a fixed water head. Two outlets are set because after testing, it was found that two M20*1.5 threaded ports are needed to discharge excess water in time to make the water head more stable and the position symmetrical on the left and right. The specific connection method is a flange port + M20*1.5 threaded port two-way head. The flange port is used to connect the water supply pipe and the flow meter, and the M20*1.5 threaded port is used to connect the box body, and a two-way head is used to achieve the overall connection.

[0039] like Figure 2As shown, the main simulation box 6 has an overall inner diameter of 1.5*0.5m*0.4m (length*width*height) and is a rectangular parallelepiped without a top cover. The box is provided with four M20*1.5 threaded ports, namely a first water inlet 601, a second water inlet 602, a first drain port 603, and a second drain port 604. The first water inlet 601 is connected to the replenishment outlet 103 through a pipe, and the second drain port 604 is connected to the fixed head discharge box 9 through a pipe. The first water inlet 601 and the second water inlet 602 are arranged on the left side, the second drain port 604 is arranged on the right side, and the first drain port 603 is arranged on the rear side. The whole is made of plexiglass, which can facilitate the observation of the movement state of the water body. The main simulation box 6 is provided with a karst simulation pipeline 7, a subway station simulation box 4, and a geological condition simulation box 3; in the karst area, during normal rainfall, water from the upstream is concentrated in the karst pipeline, and during heavy rainfall, some water will come from the stratum. The second water inlet 602 on the left side of the simulation box is used to connect a fixed water head device separately when necessary to simulate the water in the stratum when there is strong water in the upstream. The first water inlet 601 simulates the situation when there is no heavy rainfall, that is, normal rainfall, and water comes from the karst pipeline; the second drain port 604 on the right side is connected to the fixed water head discharge box 9 to fix the water head of the downstream, so that the overall head difference between the upstream and downstream can be calculated by the water head of the water inlet and the water head of the water outlet. The first drain port 603 on the rear end face is for the convenience of draining the accumulated water after the test; the specific connection method is flange port + M20*1.5 threaded port two-way head, the flange port is connected to the water pipe and the flow meter, the M20*1.5 threaded port is connected to the box body, and the overall connection is achieved with a two-way head.

[0040] like Figure 5 , Figure 6 As shown, the two ends of the karst simulation pipe 7 are respectively connected to the first water inlet 601 and the second water outlet 604, the outer diameter of the karst simulation pipe 7 is 3.5 cm, and the upper half of the karst simulation pipe 7 is provided with relatively dense first simulation holes 701, the hole diameter is 3 mm, and the hole spacing is about 3 mm. The lower half of the karst simulation pipe 7 is provided with relatively sparse second simulation holes 702, the hole diameter is 3 mm, and the hole spacing is about 6 mm, so as to simulate the unevenness of water seepage in the karst pipe.

[0041] like Figure 7 As shown, the overall inner diameter of the subway station simulation box 4 is designed to be 48cm*13cm*18cm (length*width*height), simulating the actual design proportion of the subway station. The rectangular box is provided with 5 M20*1.5 threaded ports as test ports 401. The test ports 401 are located in the middle of each surface. The threaded ports 401 are connected to the CGYL-204 flat mold pressure transmitter.

[0042] like Figure 8As shown, the geological condition simulation box 3 has an overall inner diameter of 79cm*14cm*19.5cm (length*width*height) and is a cube without a top cover. All panels are punched with third simulation holes 301 of different densities according to different geological conditions, for example, the hole diameter is 2mm and the hole spacing is 2mm. The geological condition simulation box 3 is filled with acrylic beads 302.

[0043] like Figure 1 As shown, the constant water head supply box 1 is connected to the main simulation box 6 through the first electromagnetic flowmeter 2, the karst simulation pipeline 7 is connected to the first water inlet 601 and the second drain outlet 604 of the main simulation box 6, the subway station simulation box 4 is placed above the karst simulation pipeline 7, and the other spaces are filled with geological condition simulation boxes 3 with different pore diameters and bead diameters according to different stratum conditions. The second drain outlet 604 of the main simulation box 6 is connected to the constant water head discharge box 9, and the CGYL-204 flat mold pressure transmitter is connected to the 48-channel analog signal acquisition system. The components are connected by pipes made of PVC material. The model of the analog signal acquisition system is CGCJ-7660A / 48.

[0044] The flat-die pressure transmitter in the simulation device transmits data to the computer through the analog signal acquisition system. By processing the collected data, the relationship process line between flow rate and anti-floating water level can be drawn, which is of great significance to the research on anti-floating design of subway in karst areas.

[0045] The operating steps when the present invention is carried out experiment are:

[0046] 1. Water flows into the large tank chamber of the constant head supply tank 1. At this time, the first control valve 10 is closed, and the water flows over the baffle in the constant head supply tank 1 and is discharged from the supply and drainage ports 101 and 102. At this time, the water flow in the constant head supply tank 1 will be in a constant head state.

[0047] 2. On the basis of the fixed water head, the second control valve 11 and the third control valve 12 are opened, and the water flows into the karst simulation pipeline in the main simulation box. Under the action of the water head, the water level overflows the subway station simulation box 4. The flow change is monitored by the first electromagnetic flowmeter 2, and the pressure signal is monitored by the flat mold pressure transmitter in the subway station simulation box 4. The pressure signal data is collected by the analog signal acquisition system CGCJ-7660A / 48.

[0048] 3. After the water head in the to-be-fixed-head discharge box 9 is stable, adjust the placement height of the fixed-head supply box 1 according to the test simulation requirements to simulate the changes in different upstream water volumes.

[0049] 4. Stop the water supply from the constant head supply tank and allow the water to drain naturally, simulating the changes after the water supply ends.

[0050] 5. According to different karst geological conditions, the parameters of the karst simulation pipeline 7 and the geological condition simulation box 3 are changed, acrylic beads of different particle sizes are used to fill the geological condition simulation box 3, and the experimental steps are repeated to obtain comparative experimental results;

[0051] 6. After collating the data from the analog signal acquisition system and the first and second electromagnetic flowmeters, the relationship line between the upstream water flow in the karst area and the subway anti-floating water level can be drawn. The experimental results provide important data for the actual subway anti-floating design.

[0052] The beneficial effects of the present invention are:

[0053] (1) The present invention uses organic glass to make the main simulation box design so that the simulation process can be visualized, which is convenient for understanding and observing the state of water movement under different geological conditions. Compared with traditional simulation equipment, the present invention can comprehensively and clearly observe the process of the impact of underground water in the karst area on the subway station.

[0054] (2) The present invention monitors the simulation process through components such as flat die pressure transmitters and electromagnetic flow meters. Compared with traditional manual measurement and recording methods, this monitoring method can more accurately obtain data such as water level and flow rate. The numerical records are easy to collect and can analyze the response relationship between the anti-floating water level and flow rate of subway stations in different karst water-containing media.

[0055] (3) The present invention can change and control various parameters of the constant head replenishment water tank and the geological condition simulation box. According to the actual needs of the simulation experiment, the present invention can carry out comparative experimental analysis and research under specific conditions for the complex hydrogeological conditions in the karst area. It has flexible simulation applicability, thus making the experimental data more convincing.

Claims

1. A karst area subway anti-floating simulation device and an anti-floating water level simulation method thereof, comprising a constant water head supply box, a main body simulation box, and a constant water head discharge box, wherein the constant water head supply box and the constant water head discharge box are both connected to the main body simulation box through a pipeline; characterized in that: The fixed water head supply box is provided with a partition whose height is lower than the side wall of the fixed water head supply box, and the fixed water head supply box is provided with a supply outlet and a supply drain outlet. The supply outlet is located on one side of the partition, and the supply drain outlet is located on the other side of the partition. The supply outlet is connected with the main simulation box through a pipeline; the main simulation box is made of organic glass, and the main simulation box is provided with a first water inlet, a second water inlet, a first drain outlet, and a second drain outlet. The first water inlet is connected with the supply outlet through a pipeline, and the second drain outlet is connected with the fixed water head discharge box through a pipeline. The main simulation box is provided with karst A simulation pipeline, a subway station simulation box, and a geological condition simulation box. The two ends of the karst simulation pipeline are respectively connected to the first water inlet and the second drain outlet. The upper part of the karst simulation pipeline is provided with a plurality of first simulation holes, and the lower part of the karst simulation pipeline is provided with a plurality of second simulation holes. The hole spacing of the first simulation holes is greater than the hole spacing of the second simulation holes. The subway station simulation box is provided with a test port and connected to a flat mold pressure transmitter through the test port. There are a plurality of geological condition simulation boxes, and a plurality of third simulation holes are provided on the geological condition simulation box. The geological condition simulation box is filled with acrylic beads. A first electromagnetic flowmeter is provided on the pipeline between the replenishment water outlet and the first water inlet, and the two ends of the first electromagnetic flowmeter are respectively connected to the replenishment water outlet and the first water inlet pipeline; a second electromagnetic flowmeter is provided on the pipeline between the second drainage outlet and the fixed water head drainage box, and the two ends of the second electromagnetic flowmeter are respectively connected to the second drainage outlet and the fixed water head drainage box pipeline; A first control valve is provided on the pipeline between the first electromagnetic flowmeter and the first water inlet, a second control valve is provided on the pipeline between the second drain outlet and the second electromagnetic flowmeter, and a third control valve is provided on the pipeline between the second electromagnetic flowmeter and the fixed water discharge box; The anti-floating water level simulation method comprises the following steps: S1, close the first control valve, open the water source, and the water flows into the constant water head supply box from the side close to the replenishment outlet. After the water overflows the partition, open the first control valve and the water flows out from the replenishment outlet; S2, opening the second control valve and the third control valve to allow water to flow into the karst simulation pipeline in the main simulation box, monitoring the flow change through the first electromagnetic flowmeter, and monitoring the pressure signal through the flat die pressure transmitter, and the pressure signal data is collected by the analog signal acquisition system; S3. After the water flow in the constant head discharge box is stable, the placement height of the constant head supply box is adjusted according to the test simulation requirements to simulate the data changes of different water inflows; S4, the fixed head supply tank stops supplying water, allowing the water to drain naturally, simulating the data changes after the water flow ends; S5. According to different karst geological conditions, the parameters of the karst simulation pipeline and the geological condition simulation box are changed, acrylic beads of different particle sizes are used to fill the geological condition simulation box, and steps S1 to S4 are repeated to obtain comparative experimental data; S6. Arrange the data collected by the analog signal acquisition system and the first electromagnetic flowmeter and the second electromagnetic flowmeter, and draw the relationship line between the upstream water flow in the karst area and the anti-floating water level of the subway.

2. The anti-floating simulation device for subway in karst area and the anti-floating water level simulation method thereof as claimed in claim 1, characterized in that: A test port is provided at the center of each side of the subway station simulation box, and the test port is threadedly connected to the flat die pressure transmitter. The model of the flat die pressure transmitter is CGYL-204, and the flat die pressure transmitter is connected to the analog signal acquisition system line.

3. The anti-floating simulation device for subway in karst area and the anti-floating water level simulation method thereof as claimed in claim 2, characterized in that: The first water inlet and the second water inlet are both arranged on the left side of the main simulation box, the first drainage outlet is arranged on the rear side of the main simulation box, and the second drainage outlet is arranged on the right side of the main simulation box.

4. The anti-floating simulation device for subway in karst area and the anti-floating water level simulation method thereof as claimed in claim 3 are characterized by: The internal length of the constant water head supply tank is 0.4m, the internal width is 0.4m, the internal height is 0.4m, and the height of the partition is 0.3m; the internal length of the main simulation box is 1.5m, the internal width is 0.5m, and the internal height is 0.4m; the internal length of the subway station simulation box is 48cm, the internal width is 13cm, and the internal height is 18cm.

5. The anti-floating simulation device for subway in karst area and the anti-floating water level simulation method thereof as claimed in claim 4, characterized in that: The outer diameter of the karst simulation pipe is 3.5 cm, the hole diameter of the first simulation hole is 3 mm, and the distance between adjacent holes is 3 mm; the hole diameter of the second simulation hole is 3 mm, and the distance between adjacent holes is 6 mm.

6. The anti-floating simulation device for subway in karst area and the anti-floating water level simulation method thereof as claimed in claim 5, characterized in that: The internal length of the geological condition simulation box is 79 cm, the internal width is 14 cm, and the internal height is 19.5 cm; the diameter of the third simulation hole is 2 mm, and the distance between adjacent holes is 2 mm.

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