Cylindrical underground structure excavation simulation device

Abstract

The utility model relates to a cylindrical underground structure excavation simulation device, which is characterized in that a cylindrical diaphragm wall model arranged in a test space divides an accommodating space into a test soil body area to be excavated and a peripheral pressure loading area radially from inside to outside, and a predetermined amount of heavy fluid can be injected into the test soil body area to be excavated to simulate a soil body to be excavated. A peripheral pressure loading system is arranged in the peripheral pressure loading area to simulate the pressure effect of peripheral soil on the cylindrical diaphragm wall model. During testing, heavy fluid is adopted as a to-be-excavated test soil body, excavation of the soil body can be simulated in the mode that the heavy fluid is directly discharged outwards through the first discharging system, and the excavation simulation process is very convenient and smooth; meanwhile, an external data acquisition system acquires data detected by each sensor, so that researchers can perform detailed analysis, the whole excavation process can be analyzed and evaluated in detail, and reliable reference basis is provided for actual excavation engineering.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of building engineering construction test, especially a cylindrical underground structure's excavation simulation device. BACKGROUND

[0002] With the accelerating process of urbanization, the development and utilization of underground space become more and more important. As an important part of underground structure, cylindrical underground structure plays a crucial role in urban construction. Due to its unique structural geometric characteristics, cylindrical underground structure is particularly common in underground space development. For example, subway stations, deep wells and storage tanks and other facilities widely use this structure. These cylindrical underground structures not only can effectively utilize underground space, but also have high stability and safety. They play an indispensable role in urban infrastructure construction and provide strong support for the sustainable development of the city.

[0003] The excavation of cylindrical underground structure is a complex engineering task involving multiple steps and the application of technology. First, detailed geological survey is needed to understand the nature and structure of the underground soil. Then, a suitable cylindrical structure scheme is designed to ensure its stability and safety in practical application. Then, a circular underground continuous wall (or called diaphragm wall) is constructed at the edge of the soil area to be excavated to prevent the surrounding soil from moving laterally during the subsequent excavation process. Then, the existing excavation method (generally using the top-down open excavation method) is used to excavate the soil in the area to be excavated, and the excavation depth and speed need to be strictly controlled during the excavation process to prevent serious ground settlement and serious deformation of the underground continuous wall structure. At the same time, drainage and support work need to be done to ensure the dryness and stability of the excavation area. Finally, after the excavation is completed, the structure is poured and maintained to ensure that it meets the design requirements of strength and durability.

[0004] The excavation process of cylindrical underground structure is affected by factors such as soil properties, groundwater level, and surrounding environment. As the main protective and supporting structure, the mechanical behavior (such as hoop strain and radial strain) of the underground continuous wall under external pressure (such as the pressure of the surrounding soil on the underground continuous wall or the effect of soil settlement) is a key factor affecting the efficiency and safety of excavation. Therefore, accurately simulating and measuring the mechanical behavior of the underground continuous wall under external pressure during the excavation of the cylindrical underground structure is of great significance to improve the efficiency and safety of excavation.

[0005] In the prior art, the simulation method of cylindrical underground structure excavation mainly relies on physical model box test and numerical simulation analysis. The physical model box test can intuitively reflect the mechanical behavior of the soil body, but has limitations such as high cost, complex operation, and difficulty in realizing comprehensive simulation of multiple factors. Although the numerical simulation analysis can simulate complex engineering conditions, it has high requirements for the accuracy of the soil body constitutive relation, and it is difficult to intuitively verify the simulation results. Practical new type content

[0006] The purpose of the utility model is to provide a device capable of accurately and conveniently simulating cylindrical underground structure excavation, so as to better assist cylindrical underground structure excavation construction.

[0007] The cylindrical underground structure excavation simulation device, comprising

[0008] The test cabin is internally limited to have an accommodation space;

[0009] The cylindrical diaphragm wall model is placed in the middle of the accommodation space and separates the accommodation space radially inside and outside into a to-be-excavated test soil body area and a peripheral pressure loading area. The to-be-excavated test soil body area is used to contain a predetermined amount of heavy fluid.

[0010] The peripheral pressure loading system is provided in the peripheral pressure loading area and is used to apply pressure to the cylindrical diaphragm wall model from the outside to simulate the pressure generated by the peripheral soil body on the cylindrical diaphragm wall model during the excavation process; and

[0011] The first discharge system is used to discharge the heavy fluid in the to-be-excavated test soil body area.

[0012] The utility model discloses a cylindrical underground structure excavation simulation device is by setting in the test space the cylindrical diaphragm wall model and separates the space radial inside and outside into the test soil body area and the peripheral pressure loading area of excavation, and the test soil body area can inject the predetermined amount of heavy fluid to simulate the soil body of excavation, and the peripheral pressure loading system is provided in the peripheral pressure loading area to simulate the pressure effect of the peripheral soil body to the cylindrical diaphragm wall model. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is the structural schematic diagram of cylindrical underground structure excavation simulation device.

[0014] Figure 2 It is the overhead structural schematic diagram of cylindrical underground structure excavation simulation device.

[0015] Figure 3 It is Figure 2 The sectional view along A-A direction. DETAILED DESCRIPTION

[0016] The technical scheme in the embodiments of the utility model will be described clearly and completely below with reference to the drawings, obviously, the described embodiments are only part of the embodiments of the utility model, not all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the ordinary skill in the art without making creative labor belong to the range of the utility model protection.

[0017] It should be noted that if the embodiments of the utility model involve directional indications (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, …), the directional indications are only used to explain the relative position relationship, movement condition and the like between the components in a certain specific posture (as shown in the drawings), if the specific posture changes, the directional indications also change accordingly.

[0018] If the embodiments of this utility model involve descriptions such as "first" or "second," such descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0019] This invention proposes a cylindrical underground structure excavation simulation device.

[0020] The cylindrical underground structure excavation simulation device in this embodiment, such as Figures 1-3 As shown, it includes test chamber 1, cylindrical diaphragm wall model 2, external pressure loading system 3, and first discharge system (not shown).

[0021] The test chamber 1 is made of a high-strength material and contains a defined space 10. A cylindrical diaphragm wall model 2 is placed in the center of the space 10, radially dividing the space into a test soil area 20 to be excavated and an outer pressure loading area 11. The test soil area 20 is used to hold a predetermined amount of heavy fluid 100. An outer pressure loading system 3 is located in the outer pressure loading area 11 and is used to apply pressure to the cylindrical diaphragm wall model 2 from the outside to simulate the pressure exerted by the outer soil on the cylindrical diaphragm wall model 2 during excavation. A first discharge system is used to discharge the heavy fluid 100 from the test soil area 20 to simulate the excavation of the test soil area 20. During the experiment, according to requirements, corresponding sensors (including but not limited to pressure sensors and strain sensors, etc., not shown) were first set at key locations of the simulation device. Then, a predetermined amount of heavy fluid 100 was injected into the test soil area 20 to be excavated, and the external pressure loading system 3 applied a predetermined pressure to the cylindrical diaphragm wall model 2. Next, according to the predetermined excavation speed, the heavy fluid 100 in the test soil area 20 to be excavated was gradually discharged through the first discharge system to simulate the unloading effect of the soil during the excavation process in the test soil area 20. Since the heavy fluid 100 was used as the test soil to be excavated, the excavation of the soil could be simulated by directly discharging it to the outside through the first discharge system. The excavation simulation process was very convenient and smooth. At the same time, the external data acquisition system collected the data detected by each sensor (including but not limited to the pressure and stress data of the cylindrical diaphragm wall model 2 during the experiment) for researchers to conduct detailed analysis, so as to conduct a detailed analysis and evaluation of the entire excavation process and provide a reliable reference for actual excavation projects.

[0022] It can be understood that the cylindrical diaphragm wall model 2 is made of a material with good strength to avoid serious deformation during the test to affect the test accuracy and effect. For example, the cylindrical diaphragm wall model 2 can be formed by pouring reinforced concrete, or can be made of a material with good rigidity such as steel, cast iron or aluminum alloy, tempered glass or acrylic, and the thickness can be determined according to the test requirements.

[0023] In some embodiments, the cylindrical diaphragm wall model 2 includes a bottom plate 1A and a surrounding plate 1B integrally formed or fixed to the bottom plate 1A, the bottom plate 1A and the surrounding plate 1B form an open-top containing space 10, and the cylindrical diaphragm wall model 2 is fixed to the middle position of the bottom plate 1A.

[0024] In the embodiment of the utility model, the peripheral pressure loading system 3 includes a plurality of jacks 31, and the plurality of jacks 31 are all abutted between the outer wall of the cylindrical diaphragm wall model 2 and the inner wall of the test cabin 1. By controlling the extension and retraction amount of the jacks 31, the pressure value borne by the cylindrical diaphragm wall model 2 can be adjusted, so as to simulate the pressure borne by each part of the diaphragm wall under different working conditions.

[0025] Specifically, the number and distribution mode of the jacks 31 have various embodiments. Generally speaking, the more the number of jacks 31, the more comprehensive the surrounding soil pressure simulation effect of the cylindrical diaphragm wall model 2 can be obtained, but the cost is higher. In terms of distribution mode, the jacks 31 can be distributed along the circumferential direction and / or the axial direction (i.e. the vertical direction) of the cylindrical diaphragm wall model 2. Among them, the jacks 31 can be distributed circumferentially around the cylindrical diaphragm wall model 2, which can ensure that the cylindrical diaphragm wall model 2 can be effectively subjected to pressure in the circumferential direction, and the circumferential stress uniformity of the cylindrical underground structure can be simulated. The axial distribution can simulate the vertical stress unevenness of the cylindrical diaphragm wall model 2, and detect the difference of the soil pressure at different depths reflecting the actual excavation construction. Preferably, a plurality of groups (such as three groups as shown) of jacks 31 are arranged in the peripheral pressure loading area 11 along the axial direction of the cylindrical diaphragm wall model 2, and each group of jacks 31 has a plurality of (such as four as shown) jacks 31 distributed along the circumferential direction of the cylindrical diaphragm wall model 2. During the test, uniform or non-uniform pressure can be applied to the cylindrical diaphragm wall model 2 in the axial and circumferential directions according to the actual working condition and test requirements. Figure 3 Figure 3

[0026] ​​Further, the two ends of the jack 31 are respectively provided with a gasket 31 and 33 between the cylindrical wall connecting model 2 and the test cabin 1, and abut the outer wall of the cylindrical wall connecting model 2 and the inner wall of the test cabin 1 through the gaskets 32 and 33. The side of the gasket abutting the outer wall of the cylindrical wall connecting model 2 and the inner wall of the test cabin 1 is arc-shaped and suitable for the shapes of the two, so as to more stably and uniformly transmit the pressure.

[0027] Understandably, during the test, the jack 31 will generate outward pressure on the test cabin 1. If the cabin wall of the test cabin 1 is thick and strong enough, the test cabin 1 can resist the pressure of the jack 31 without obvious deformation and can well provide a good reaction force to the jack 31, but this will increase the manufacturing cost of the test cabin 1 and cause material waste. Therefore, in order to balance the cost and test effect, the utility model also has a reaction frame 4 to provide a supporting force to the test cabin 1 to avoid serious deformation of the test cabin 1 due to the pressure of the jack 31.

[0028] Specifically, the reaction frame 4 includes a plurality of rigid first support rods 41 arranged on the outer wall of the test cabin 1 and corresponding to the positions of the jacks 31, and a first inclined support 42 having an upper end connected to the upper end of the first support rod 41. The lower end of the first support rod 41 extends out of the bottom of the test cabin 1 and is fixed to the ground or other support table, and the upper end extends out of the test cabin 1. The lower end of the first inclined support 42 is fixed to the ground or other support table to support the test cabin 1 at this position, thereby preventing serious deformation of the test cabin 1 at this position and providing a stable reaction force.

[0029] Understandably, in order to further improve the structural strength of the test cabin 1, a plurality of second support rods 51 are fixed to the outer wall of the test cabin 1 between the circumferentially adjacent first support rods 41. The lower end of the second support rod 51 extends to the bottom of the test cabin 1 and is connected to the ground or other support table, and the upper end extends out of the test cabin 1. The top portions of the opposite second support rods 51 are further connected to a reinforcing rod 52 to provide a radial inward tensile force to the second support rods 51, thereby further preventing the test cabin 1 from deforming due to the pressure of the jack 31.

[0030] In some practical conditions where the soil has a high water content, it is often necessary to drain the surrounding soil before excavation. Thus, in order to simulate the pressure and deformation of the cylindrical diaphragm wall model 2 caused by drainage, a predetermined amount of water or aqueous solution can be injected into the peripheral pressure loading area 11, and a second drainage system (not shown) can be provided for draining the water or aqueous solution in the peripheral pressure loading area 11 to lower the water level in the peripheral pressure loading area 11 to a predetermined position, and then simulating the excavation process of the soil, realizing the construction process of "first dewatering, then excavation", so as to better simulate the actual excavation engineering. Specifically, the second drainage system has various embodiments in the prior art, for example, the second drainage system includes a water outlet hole 13 provided on the bottom wall of the test chamber 1, a drainage pipe (not shown) connected to the water outlet hole, and a valve (not shown), etc. The drainage pipe can be directly connected to the liquid recovery area or connected to a water pump (not shown). How to set and how to drain are not described here.

[0031] It should be noted that the heavy fluid 100 belongs to the prior art and has various embodiments, for example, a high-density lithium heteropolytungstate aqueous solution can be used. The lithium heteropolytungstate aqueous solution is a non-toxic, odorless, easily soluble, easily prepared, stable, high recovery, and safe inorganic heavy liquid. Due to its density can be adjusted in a large range, it is often used as a heavy fluid 100 to simulate soil. In practical applications, the concentration of the lithium heteropolytungstate aqueous solution can be adjusted to match the unit volume weight of the soil to be excavated.

[0032] It can be understood that the density of the lithium heteropolytungstate aqueous solution can be adjusted from 1.1 g / ml to 3.1 g / ml as needed. The basic steps of adjusting the density of the lithium heteropolytungstate aqueous solution are as follows: first, determine the density of the soil to be excavated; then, according to the required density, calculate how much lithium tungstate (Li2WO4) or other lithium tungstate and water are needed to prepare the solution; then, add the calculated predetermined amount of lithium tungstate (Li2WO4) or other lithium tungstate to the water, stir well until completely dissolved, and if necessary, the density of the solution can be fine-tuned by adding more lithium tungstate (Li2WO4) or other lithium tungstate or water. Finally, use a density meter or other measuring tools to test the density of the lithium heteropolytungstate aqueous solution to ensure that it meets the design requirements.

[0033] It can be understood that the heavy fluid 100 in the test soil area 20 to be excavated can adopt a lithium heteropolytungstate aqueous solution with uniform density, but in actual working conditions, the soil to be excavated can have non-uniform characteristics from top to bottom (for example, a soil-rock composite stratum including a soft soil layer on the top and a rock layer on the bottom), and the soil with non-uniform characteristics has different densities. Therefore, in order to simulate the excavation process of the soil with non-uniform characteristics, the heavy fluid 100 in the test soil area 20 to be excavated includes multiple layers of lithium heteropolytungstate aqueous solutions with different densities, and a water-impermeable film (not shown) is arranged between the lithium heteropolytungstate aqueous solutions with different densities to separate them. Specifically, the lithium heteropolytungstate aqueous solution in the test soil area 20 to be excavated can be two layers, three layers or more layers. When the lithium heteropolytungstate aqueous solution is two layers, the soft soil layer on the top and the rock layer on the bottom can be simulated respectively.

[0034] It can be understood that the film can be made of polytetrafluoroethylene (PTFE) or polyurethane (PU), and a microporous structure is created on the surface of the film. The diameters of the micropores are designed to be large enough to prevent the solution from penetrating and small enough to allow the gas to pass through, so that the gas in the space covered by the film can be discharged, thereby improving the test accuracy and effect.

[0035] Further, the utility model also includes a central shaft 6 arranged in the periphery of the cylindrical diaphragm wall model 2, and the central shaft 6 is preferably made of high-strength metal materials such as steel, cast iron and aluminum alloy. The outer wall of the central shaft 6 and the inner wall of the cylindrical diaphragm wall model 2 form the test soil excavation area. The arrangement of the central shaft 6 can facilitate the laying of the film and improve the overall strength of the simulation device.

[0036] It can be understood that the first discharge system has various embodiments in the prior art, for example, including a water pump, a flow meter (not shown), a valve (not shown), a discharge pipe (not shown) and other components. The lower end of the discharge pipe extends to the bottom position of the corresponding layer of heavy fluid. The flow meter is used to monitor the discharge speed of the heavy fluid 100 in real time. The specific discharge speed can be determined according to the test requirements.

[0037] As shown in FIG. 4, the second discharge system includes a second water pump 5, a second flow meter 6 and a second discharge pipe 7. The second water pump 5 is connected to the second flow meter 6, and the second flow meter 6 is connected to the second discharge pipe 7. Figures 1-3As shown, the utility model takes the cylindrical underground structure excavation in soil-rock composite stratum as an example, introduces the excavation simulation process of the utility model: S1, according to the soil-rock composite stratum characteristics simulated as required, prefabricate two corresponding density heavy fluid 100 (preferably lithium heteropolytungstate aqueous solution), and set pressure sensor, displacement sensor and strain sensor and other sensors at the key position of cylindrical ground connecting wall model 2 and other components; S2, a layer of latex film (not shown) is sleeved at the interval between cylindrical ground connecting wall model 2 and central axis 6 (i.e. the interval of the soil body to be excavated 11), to ensure the sealing property; S3, a predetermined amount of first layer heavy fluid 100 (simulating rock stratum) is injected into the interval, and after the first layer heavy fluid is laid on the surface of the first layer heavy fluid with impermeable film arrangement, a predetermined amount of second layer heavy fluid 100 (simulating soft soil layer) is injected, and at the same time, a predetermined amount of water or aqueous solution is injected in the peripheral pressure loading area 11. S4, heavy fluid 100 and water or aqueous solution tend to be stable after a period of time; S5, according to the engineering design data, the size of the earth pressure at each position is calculated, and the corresponding displacement-time curve is set for each jack 31 in the system; S6, the water or aqueous solution in the peripheral pressure loading area 11 is discharged through the second drainage system, so that the water level in the peripheral pressure loading area 11 gradually decreases to the predetermined position; S7, the heavy fluid 100 in the soil body to be excavated 20 is discharged through the first drainage system in the manner of upper layer first and lower layer later, so that the water level of the heavy fluid 100 in the soil body to be excavated 20 decreases to the predetermined position; S8, steps S6 and S7 are repeated until the water or aqueous solution and heavy fluid 100 in the peripheral pressure loading area 11 and the soil body to be excavated 20 are completely discharged or substantially completely discharged, that is, one simulation test is completed. The excavation simulation process is very convenient; at the same time, the external data acquisition system collects the data detected by each sensor, so that researchers can conduct detailed analysis, so as to analyze and evaluate the entire excavation process in detail, and provide reliable reference basis for actual excavation engineering.

[0038] It should be explained that the sensor and the external data acquisition system are both prior art and are well known to those skilled in the art, and the specific setting mode and working principle of the sensor and the data acquisition system will not be described here. At the same time, how to process and analyze the collected data also belongs to the prior art, and will not be described here again. The main purpose of the utility model is how to simulate the excavation of the cylindrical underground structure and obtain the corresponding data.

[0039] The above only describes the preferred embodiments of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation made by using the utility model specification and the drawings, or direct / indirect application in other related technical fields is included in the patent protection range of the utility model.

Claims

1. A cylindrical underground structure excavation simulation device, characterized by, The utility model relates to a soil excavation test device, comprising: a test cabin, which is internally defined with a containing space; a cylindrical diaphragm wall model, which is arranged in the middle of the containing space and separates the containing space into a test soil area to be excavated and a peripheral pressure loading area in the radial direction, the test soil area to be excavated being used for containing a predetermined amount of heavy fluid; a peripheral pressure loading system, which is arranged in the peripheral pressure loading area and is used for applying pressure to the cylindrical diaphragm wall model from the outside to simulate the pressure generated by the peripheral soil on the cylindrical diaphragm wall model during excavation; and a first drainage system, which is used for draining the heavy fluid in the test soil area to be excavated.

2. The cylindrical underground structure excavation simulation apparatus according to claim 1, characterized by: The peripheral pressure loading system comprises a plurality of jacks, which are distributed along the circumferential and / or axial direction of the cylindrical diaphragm wall model and abut between the outer wall of the cylindrical diaphragm wall model and the inner wall of the test cabin body.

3. The cylindrical underground structure excavation simulation apparatus according to claim 2, characterized by: A plurality of groups of jacks are arranged in the axial direction of the cylindrical diaphragm wall model in the peripheral pressure loading area, and each group of jacks comprises a plurality of jacks distributed in the circumferential direction of the cylindrical diaphragm wall model.

4. The cylindrical underground structure excavation simulation apparatus according to claim 2, characterized by: The two ends of the jacks are provided with gaskets between the cylindrical diaphragm wall model and the test cabin, and abut against the outer wall of the cylindrical diaphragm wall model and the inner wall of the test cabin through the gaskets.

5. The cylindrical underground structure excavation simulation apparatus according to claim 2, characterized by: Further comprising a plurality of first struts arranged on the outer wall of the test cabin and corresponding to the positions of the jacks, and a first inclined strut connected to the upper ends of the first struts, the lower ends of the first struts extending out of the bottom of the test cabin and being fixed to the ground, and the upper ends extending out of the test cabin, and the lower ends of the first inclined strut being fixed to the ground.

6. The cylindrical underground structure excavation simulation apparatus according to claim 2, characterized by: The outer wall of the test cabin is further circumferentially fixed with a plurality of second struts located between circumferentially adjacent first struts, the lower ends of the second struts extending to the bottom of the test cabin and being connected to the ground, and the upper ends extending out of the test cabin, and a reinforcing rod being further connected between the top portions of the opposite second struts.

7. The cylindrical underground structure excavation simulation apparatus according to claim 1, characterized by: Further comprising a second drainage system for draining the water or aqueous solution contained in the peripheral pressure loading area.

8. The cylindrical underground structure excavation simulation apparatus according to claim 1, characterized by: The heavy fluid in the test soil area to be excavated adopts a lithium heteropolytungstate aqueous solution with uniform density, or comprises a plurality of layers of lithium heteropolytungstate aqueous solutions with different densities, and a water-impermeable film is arranged between the lithium heteropolytungstate aqueous solutions with different densities to separate them.

9. The cylindrical underground structure excavation simulation apparatus according to any one of claims 1 to 8, characterized by: The first drainage system comprises a water pump, a flow meter, a valve and a drainage pipe, the lower end of the drainage pipe extending to the bottom position of the corresponding layer of heavy fluid, and the flow meter being used for monitoring the drainage speed of the heavy fluid in real time.

10. The cylindrical underground structure excavation simulation apparatus according to any one of claims 1 to 8, characterized by: Further comprising a central shaft arranged in the inner periphery of the cylindrical diaphragm wall model, and the outer wall of the central shaft and the inner wall of the cylindrical diaphragm wall model surrounding the test soil excavation area.

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