Cylindrical underground structure excavation test device and method

Abstract

The invention relates to a cylindrical underground structure excavation test device and method, and the device is characterized in that a cylindrical diaphragm wall model divides an accommodation space into a to-be-excavated test soil body region and a peripheral pressure loading region in the radial direction from inside to outside; wherein a vertical guide shaft is arranged in the to-be-excavated test soil body area, the to-be-excavated test soil body area and the cylindrical diaphragm wall model define an annular test soil body filling area, and the annular test soil body filling area is vertically divided into a plurality of sub-filling areas by annular partition plates capable of vertically and movably sleeving the vertical guide shaft so as to fill a test soil body in a layered manner; 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, the annular partition plates are sequentially lifted upwards from top to bottom, and the test soil bodies of the corresponding sub-filling areas are lifted out of the test soil body area to be excavated, so that the unloading effect mode of the soil bodies in the test soil body area to be excavated in the soil body excavation process is simulated, and the excavation simulation process is very convenient and smooth.

Description

Technical Field

[0001] The invention relates to the technical field of construction engineering test, and in particular to an excavation test device and method for a cylindrical underground structure. Background Art

[0002] With the continuous acceleration of urbanization, the development and utilization of underground space has become increasingly important. As an important part of underground structure, cylindrical underground structure plays a vital role in urban construction. Due to its unique structural geometric characteristics, cylindrical underground structure is particularly common in underground space development. For example, facilities such as subway stations, deep wells and storage tanks have widely adopted this structure. These cylindrical underground structures can not only 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 cities.

[0003] The excavation of cylindrical underground structures is a complex engineering task involving the application of multiple steps and technologies. First, a detailed geological survey is required to understand the properties and structure of the underground soil layer. Then, a suitable cylindrical structure scheme is designed to ensure its stability and safety in practical application. Then, a circular underground continuous wall (or ground-connected wall) is constructed at the edge of the soil area to be excavated to prevent the lateral movement of the surrounding soil to the excavation area during the subsequent excavation process; then, the soil in the excavation area is excavated using the existing excavation method (generally using the open excavation method from top to bottom), and during the excavation process, the excavation depth and speed need to be strictly controlled 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 well to ensure the dryness and stability of the excavation area. Finally, after the excavation is completed, the structure is cast and maintained to ensure that it meets the strength and durability required by the design.

[0004] The excavation process of cylindrical underground structures will be affected by factors such as soil properties, groundwater level, and surrounding environment. As the main protection and support structure, the mechanical behavior of the underground continuous wall under external pressure (such as the pressure of the surrounding soil on the underground continuous wall, or the action of soil settlement) (such as circumferential strain and radial strain) is a key factor affecting excavation efficiency and safety. Therefore, if the mechanical behavior of the underground continuous wall under external pressure during the excavation of the cylindrical underground structure can be accurately simulated and measured, it is of great significance to improve the excavation efficiency and safety.

[0005] In the existing technology, the test method for excavation of cylindrical underground structures 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, but it has limitations such as high cost, complex operation, and difficulty in achieving multi-factor comprehensive simulation. Although numerical simulation analysis can simulate complex engineering conditions, it has high requirements on the accuracy of the soil constitutive relationship and it is difficult to intuitively verify the simulation results. Summary of the invention

[0006] The purpose of the present invention is to provide a device and method for accurately and conveniently conducting cylindrical underground structure excavation tests, so as to better assist the cylindrical underground structure excavation construction.

[0007] The cylindrical underground structure excavation test device proposed by the present invention comprises:

[0008] A test chamber, wherein a containing space is defined inside the test chamber;

[0009] The cylindrical ground-connected wall model is placed in the middle of the accommodation space, and the accommodation space is radially divided into a test soil area to be excavated and a peripheral pressure loading area;

[0010] A vertical guide shaft, which is arranged in the middle of the test soil area to be excavated and forms a ring-shaped test soil filling space with the cylindrical ground-connected wall model;

[0011] A plurality of annular partition plates, which are vertically movable and sleeved on the vertical guide shaft, and the annular partition plates are adapted to the test soil filling space to vertically divide the test soil filling space into a plurality of sub-filling areas, and a hanging portion for lifting and placing the annular partition plates is provided above the annular partition plates; and

[0012] The peripheral pressure loading system is arranged in the peripheral pressure loading area and is used to apply pressure to the cylindrical ground-connected wall model from the outside to simulate the pressure generated by the peripheral soil on the cylindrical ground-connected wall model during excavation.

[0013] The cylindrical underground structure excavation test method proposed by the present invention comprises the following steps:

[0014] S1. After the corresponding sensors are set on the test device, multiple annular partition plates are sequentially placed on the vertical guide shaft and filled with compacted test soil layer by layer;

[0015] S2, driving the peripheral pressure loading system to apply a predetermined pressure to the cylindrical ground-connected wall model;

[0016] S3. According to the predetermined excavation speed, the annular partition plates are lifted up along the vertical guide shaft from top to bottom at the hanging part, and the test soil accumulated thereon is lifted out of the test soil area to be excavated, so as to simulate the unloading effect of the soil during the excavation of the test soil area to be excavated, until all the annular partition plates are lifted out of the test soil area to be excavated.

[0017] The cylindrical underground structure excavation test device of the present invention is composed of a cylindrical ground-connected wall model arranged in the test space, which radially divides the accommodating space into a test soil area to be excavated and a peripheral pressure loading area. The test soil area to be excavated is provided with a vertical guide shaft and forms a ring-shaped test soil filling area with the cylindrical ground-connected wall model. The ring-shaped test soil filling area is vertically divided into multiple sub-filling areas by a ring-shaped partition plate that can be vertically moved and sleeved on the vertical guide shaft for layered filling of the test soil. The peripheral pressure loading area is provided with a peripheral pressure loading system to simulate the pressure effect of the peripheral soil on the cylindrical ground-connected wall model. During the test, first, according to the needs, after the corresponding sensors are set on the test device, multiple annular partition plates are sequentially sleeved on the vertical guide shaft and the test soil is filled and compacted layer by layer; then the pressure loading system applies a predetermined pressure to the cylindrical ground-connected wall model; then, according to the predetermined excavation speed, from top to bottom, the annular partition plates are lifted up along the vertical guide shaft at the hanging part, and the test soil accumulated in the sub-filling area above it is lifted out of the test soil area to be excavated, so as to simulate the unloading effect of the soil during the excavation of the test soil area to be excavated, and by lifting the annular partition plates from top to bottom in turn and lifting the test soil in the corresponding sub-filling area out of the test soil area to be excavated, so as to simulate the unloading effect of the soil during the excavation of the test soil area to be excavated, the excavation simulation process is very convenient and smooth; at the same time, the external data acquisition system collects the data detected by each sensor for researchers to conduct detailed analysis, so as to conduct detailed analysis and evaluation of the entire excavation process, and provide a reliable reference basis for actual excavation projects. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of the present invention.

[0019] Figure 2 It is a cross-sectional view of the present invention after filling the test soil body.

[0020] Figure 3 is a three-dimensional schematic diagram of an embodiment of the present invention when the annular partition plate is not inserted;

[0021] Figure 4 is a three-dimensional schematic diagram of an embodiment of the present invention when the annular partition plate is not inserted;

[0022] Figure 5 is a three-dimensional schematic diagram of another embodiment of the present invention when the annular partition plate is not inserted;

[0023] Figure 6 is a cross-sectional view of an embodiment of a partition plate of the present invention;

[0024] Figure 7 is a cross-sectional view of another embodiment of a partition plate of the present invention. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. 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 are within the scope of protection of the present invention.

[0026] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial...), then the directional indication is only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] If there are descriptions involving "first" or "second" in the embodiments of the present invention, the descriptions of "first" or "second" are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] A first aspect of the present invention provides a cylindrical underground structure excavation test device.

[0029] In the embodiment of the present invention, Figure 1-7 As shown, the cylindrical underground structure excavation test device includes a test chamber 1, a cylindrical ground-connected wall model 2, a vertical guide shaft 4, a plurality of annular partition plates 5 and a peripheral pressure loading system 3.

[0030] The test chamber 1 is made of a material with good strength, and a containing space 10 is defined inside the test chamber 1. The cylindrical ground-connected wall model 2 is placed in the middle of the containing space 10, and the containing space 10 is radially divided into a test soil area 20 to be excavated and a peripheral pressure loading area 11. The vertical guide shaft 4 is arranged in the middle of the test soil area 20 to be excavated, and forms a ring-shaped test soil filling space 201 with the cylindrical ground-connected wall model. The vertical guide shaft 4 is preferably made of high-strength metal materials such as steel, cast iron, and aluminum alloy. A plurality of the annular partition plates 5 can be vertically movably sleeved on the vertical guide shaft 4, so that the annular partition plates 5 can move vertically along the vertical guide rail to ensure the stability of the vertical movement of the annular partition plates 5, and the annular partition plates 5 are adapted to the test soil filling space 201 to vertically divide the test soil filling space 201 into a plurality of sub-filling areas 2011, and a hanging portion 50 for lifting and placing the annular partition plates 5 is provided above the annular partition plates 5. The peripheral pressure loading system 3 is arranged in the peripheral pressure loading area 11, and is used to apply pressure to the cylindrical ground-connected wall model 2 from the outside to simulate the pressure generated by the peripheral soil on the cylindrical ground-connected wall model 2 during the excavation process. During the test, firstly, according to the needs, the corresponding sensors (including but limited to pressure sensors and strain sensors, etc., not shown) are set at the key positions of the test device, and then the annular partition plates 5 are sequentially sleeved on the vertical guide shaft 4 and the compacted test soil 100 is filled layer by layer; then the pressure loading system applies a predetermined pressure to the cylindrical ground-connected wall model; then, according to the predetermined excavation speed, from top to bottom, the annular partition plate 5 is lifted up along the vertical guide shaft 4 at the hanging part 50, and the test soil 100 accumulated in the sub-filling area 2011 above it is lifted out of the test soil area 20 to be excavated, so as to simulate the excavation of the soil in the test soil area 20 to be excavated. The unloading effect of the soil during the excavation process is simulated by lifting the annular partition plate 5 from top to bottom in sequence and lifting the test soil 100 of the corresponding sub-filling area 2011 out of the test soil area 20 to be excavated to simulate the unloading effect of the soil during the excavation of the test soil area 20 to be excavated. The excavation simulation process is very convenient and smooth. At the same time, the external data acquisition system collects the data detected by each sensor (including but not limited to the pressure and stress data of the cylindrical ground-connected wall model 2 during the test) for researchers to conduct detailed analysis, so as to conduct detailed analysis and evaluation of the entire excavation process, and provide a reliable reference basis for actual excavation projects.

[0031] It is understandable that the cylindrical ground-connected wall model 2 is made of a material with good strength to avoid serious deformation during the test and affect the test accuracy and effect. For example, the cylindrical ground-connected wall model 2 can be cast by reinforced concrete, or can be made of a metal with good rigidity (such as steel, cast iron or aluminum alloy, etc.), tempered glass or acrylic, and its thickness can be determined according to the test requirements.

[0032] In some embodiments, the cylindrical ground-connected wall model 2 includes a base plate 1A and a surrounding plate 1B integrally formed or fixed to the base plate 1A. The base plate 1A and the surrounding plate 1B form a receiving space 10 with an open top, and the cylindrical ground-connected wall model 2 is fixed in the middle position of the base plate 1A.

[0033] In an embodiment of the present invention, the peripheral pressure loading system 3 includes a plurality of jacks 31, and the plurality of jacks 31 are all placed between the outer wall of the cylindrical ground-connected wall model 2 and the inner wall of the test chamber 1. By controlling the expansion and contraction amount of the jacks 31, the pressure value borne by the cylindrical ground-connected wall model 2 can be adjusted, thereby simulating the pressure borne by various parts of the ground-connected wall under different working conditions.

[0034] Specifically, there are multiple implementations for the number and distribution of the jacks 31. Generally speaking, the more jacks 3 there are, the more comprehensive the simulation of the surrounding soil pressure can be obtained for the cylindrical ground wall model 2, but the cost is higher. In terms of distribution, the jacks 31 can be distributed along the circumferential and / or axial (i.e., vertical) directions of the cylindrical ground wall model 2. Among them, the jacks 31 can be distributed circumferentially around the cylindrical ground wall model 2 to ensure that the cylindrical ground wall model 2 can obtain effective pressure in the circumferential direction, and can simulate the uniform circumferential force on the cylindrical underground structure. The axial distribution can simulate the uneven vertical force on the cylindrical ground wall model 2, and detect the soil pressure differences at different depths in the actual excavation construction. Preferably, a plurality of groups (such as Figure 3 The figure shows the situation of three groups) of jacks 31, each group of jacks 31 has a plurality of (such as Figure 3 (The figure shows four cases) The jacks 31 are distributed circumferentially along the cylindrical ground-anchored wall model 2. During the test, uniform or non-uniform pressure can be applied to the cylindrical ground-anchored wall model 2 in the axial and circumferential directions according to the actual working conditions and test requirements.

[0035] Furthermore, pads 31 and 33 are respectively provided between the two ends of the jack 31 and the cylindrical ground-connected wall model 2 and the test chamber 1, and the pads 32 and 33 are used to abut against the outer wall of the cylindrical ground-connected wall model 2 and the inner wall of the test chamber 1. The side of the pad abutting against the outer wall of the cylindrical ground-connected wall model 2 and the inner wall of the test chamber 1 is an arc shape that is suitable for the two, so as to transmit pressure more stably and evenly.

[0036] It is understandable that during the test, the jack 31 will generate outward pressure on the test chamber 1. If the wall of the test chamber 1 is thick and strong enough, the test chamber 1 can cope with the pressure of the jack 31 without obvious deformation, and can provide a good reaction force to the jack 31 to improve the test accuracy and effect. However, this will increase the manufacturing cost of the test chamber 1 and cause material waste. Therefore, in order to balance the cost and test effect. The present invention is also provided with a reaction frame 6 to provide support for the test chamber 1 to prevent the test chamber 1 from being severely deformed due to the pressure of the jack 31.

[0037] Specifically, the reaction frame 6 includes a plurality of rigid first struts 61 which are arranged on the outer wall of the test chamber 1 and correspond to the position of the jack 31, and a first diagonal strut 62 whose upper end is connected to the upper end of the first strut 61. The lower end of the first strut 61 extends out of the bottom of the test chamber 1 and is fixedly connected to the ground or other supporting surfaces, while the upper end extends out of the test chamber 1. The lower end of the first diagonal strut 62 is fixed to the ground or other supporting surfaces to support the test chamber 1 at this position, thereby preventing serious deformation of the test chamber 1 at this position and providing a stable reaction force.

[0038] It can be understood that in order to further improve the structural strength of the test cabin 1, the outer wall of the test cabin 1 is also circumferentially fixed with multiple second struts 71 located between circumferentially adjacent first struts 61, the lower ends of the second struts 71 extend to the bottom of the test cabin 1 and are connected to the ground or other supporting surfaces, and the upper ends extend out of the test cabin 1, and the top of the second struts 71 is also connected to a second diagonal brace 72, the lower ends of the second diagonal brace 72 are fixed to the ground or other supporting surfaces to support the test cabin 1 at this position, thereby preventing serious deformation of the test cabin 1 at this position.

[0039] In some actual working conditions where the soil has a high water content, it is often necessary to drain the surrounding soil before excavation. Therefore, in order to simulate the pressure and deformation effects of drainage on the cylindrical ground-connected wall model 2, a predetermined water or aqueous solution can be injected into the peripheral pressure loading area 11, and a discharge system (not shown) can be set up to discharge the water or aqueous solution in the peripheral pressure loading area 11, so as to lower the water level of the water or aqueous solution in the peripheral pressure loading area 11 to a predetermined position, and then simulate the excavation process of the soil, and realize the construction process of "first lowering water, then excavating", so as to better simulate the actual excavation project. Specifically, there are many implementation methods of the discharge system in the prior art. For example, the discharge system includes a water outlet 13 provided on the bottom wall of the test cabin 1, a drain pipe (not shown) connected to the water outlet, and a valve (not shown) and other components. The drain pipe can be directly connected to the liquid recovery area or connected to a water pump (not shown). The specific setting and discharge are not repeated here as the prior art.

[0040] It can be understood that there are multiple implementations of the annular partition plate 5. As a preferred implementation, as shown in the figure, the inner edge of the annular partition plate 5 has an upwardly extending sleeve 51, and the guide sleeve can be vertically movably sleeved on the vertical guide shaft 4 and adapted to the vertical guide shaft 4 to improve the stability of the vertical movement of the annular partition plate 5 along the vertical guide shaft 4. The hanging portion 50 is provided at the top of the sleeve 51, which can be a flange radially extending from the top of the sleeve 51, or a hanging ring provided at the top of the sleeve 51, etc.

[0041] In the above embodiment, the sleeve body 51 is a round straight tube, and the annular partition plate 5 is vertical (see Figure 6 ) or tilted to (see Figure 7 ) When the annular partition plate 5 is arranged perpendicular to the axis of the sleeve 51, the partition plate is sleeved behind the vertical guide shaft 4, and the annular partition plate 5 is in a horizontal state (see Figure 1 ), and if the annular partition plate 5 is set inclined to the axis of the sleeve 51, the partition plate is sleeved on the vertical guide shaft 4, and the annular partition plate 5 is in an inclined state. The inclined setting method can make the test soil filled in each sub-filling area 2011 simulate the uneven distribution of strata in nature, and the test range is wider.

[0042] It can be understood that the annular partition plate 5 and the hanging portion 50 can be welded separately or integrally formed on the sleeve body 51.

[0043] The second aspect of the present invention also proposes a test method using the cylindrical underground structure excavation test device of the present invention. After introducing the implementation mode of the cylindrical underground structure excavation test device of the present invention, the implementation mode of the cylindrical underground structure excavation test method of the present invention will be introduced next. The specific structure of the cylindrical underground structure excavation test device is detailed in the aforementioned embodiment, and the repeated parts will not be repeated.

[0044] In an embodiment of the present invention, the cylindrical underground structure excavation test method comprises the steps of:

[0045] S1. After the corresponding sensors are set on the test device, a plurality of annular partition plates 5 are sequentially sleeved on the vertical guide shaft 4 and the test soil 100 is filled and compacted layer by layer.

[0046] Specifically, the specific process of sequentially inserting the annular partition plates 5 into the vertical guide shaft 4 and filling and compacting the test soil 100 layer by layer is as follows: first, the first annular partition plate 5 sleeved on the vertical guide shaft 4 is moved down along the vertical guide shaft 4 to the bottom of the test soil filling space 201, and the first layer of test soil 100 is filled and compacted above the first annular partition plate 5, and the top surface of the first layer of test soil 100 is flush with the hanging part 50 or slightly higher than the hanging part 50; then, the second annular partition plate 5 is sleeved on the vertical guide shaft 4 and the first annular partition plate 5 is inserted into the vertical guide shaft 4 and the second ... The two annular partition plates 5 move down to be supported by the top surface of the first layer of test soil 100 and / or the hanging part 50, and the second layer of test soil 100 is filled and compacted above the second annular partition plate 5. The second layer of test soil and the first layer of test soil 100 may be soils with the same or different properties. If they are test soils 100 with different properties, composite stratum structures can be simulated. Then, the above operations are continued until all the annular partition plates 5 are mounted on the vertical guide shaft 4 and the filling and compaction operations of the predetermined number of layers of test soil 100 are completed.

[0047] After completing the filling and compaction of the predetermined number of test soil layers, it can be allowed to stand for a period of time. This process allows the soil to compact naturally, providing the necessary stability and authenticity for simulating the actual underground environment.

[0048] S2. Drive the peripheral pressure loading system to apply a predetermined pressure to the cylindrical ground-connected wall model.

[0049] In an embodiment of the present invention, the peripheral pressure loading system 3 includes a plurality of jacks 31, and the plurality of jacks 31 are all placed between the outer wall of the cylindrical ground-connected wall model 2 and the inner wall of the test chamber 1. By controlling the expansion and contraction amount of the jacks 31, the pressure value borne by the cylindrical ground-connected wall model 2 can be adjusted, thereby simulating the pressure borne by various parts of the ground-connected wall under different working conditions.

[0050] Specifically, there are multiple implementations for the number and distribution of the jacks 31. Generally speaking, the more jacks 31 there are, the more comprehensive the surrounding soil pressure simulation effect can be obtained by the cylindrical ground wall model 2, but the cost is higher. In terms of distribution, the jacks 31 can be distributed along the circumferential and / or axial (i.e. vertical) directions of the cylindrical ground wall model 2. Among them, the jacks 31 can be distributed circumferentially around the cylindrical ground wall model 2 to ensure that the cylindrical ground wall model 2 can obtain effective pressure in the circumferential direction, which can simulate the uniform circumferential force of the cylindrical underground structure. The axial distribution can simulate the uneven vertical force of the cylindrical ground wall model 2, and detect the soil pressure differences at different depths in the actual excavation construction. Preferably, a plurality of groups (such as Figure 3 The figure shows the situation of three groups) of jacks 31, each group of jacks 31 has a plurality of (such as Figure 3(The figure shows four cases) The jacks 31 are distributed circumferentially along the cylindrical ground-anchored wall model 2. During the test, uniform or non-uniform pressure can be applied to the cylindrical ground-anchored wall model 2 in the axial and circumferential directions according to the actual working conditions and test requirements.

[0051] In some preferred embodiments, step S2 includes a process of applying a predetermined pressure to the outer side of the cylindrical ground-anchored wall model 2 by means of jacks 31 distributed circumferentially and / or axially (ie vertically) around the cylindrical ground-anchored wall model 2 .

[0052] S3. According to the predetermined excavation speed, from top to bottom, the annular partition plate 5 is lifted up along the vertical guide shaft 4 at the hanging part 50, and the test soil 100 accumulated in the sub-filling area 2011 above it is lifted out of the test soil area 20 to be excavated, so as to simulate the unloading effect of the soil in the test soil area 20 to be excavated, until all the annular partition plates 5 are lifted out of the test soil area 20 to be excavated, and the test operation is completed. The excavation simulation process is very convenient and smooth by successively lifting the annular partition plates 5 from top to bottom and lifting the test soil 100 of the corresponding sub-filling area 2011 out of the test soil area 20 to be excavated, so as to simulate the unloading effect of the soil in the test soil area 20 to be excavated. At the same time, the data detected by each sensor is collected by the external data acquisition system for detailed analysis by researchers.

[0053] In some actual working conditions where the soil has a high water content, it is often necessary to drain the surrounding soil before excavation. Therefore, in order to simulate the pressure and deformation effects of drainage on the cylindrical ground-connected wall model 2, the step S1 also includes the process of injecting a predetermined amount of water or aqueous solution into the peripheral pressure loading area 11. In the step S3, before each lifting of the annular partition plate 5, it also includes the process of discharging a predetermined amount of water or aqueous solution in the peripheral pressure loading area 11 through a discharge system (not shown) to lower the water level of the water or aqueous solution in the peripheral pressure loading area 11 to a predetermined position, so as to realize the construction process of "first lowering water, then excavating", so as to better simulate the actual excavation project. Specifically, the discharge system has a variety of implementation methods in the prior art. For example, the discharge system includes a water outlet 13 provided on the bottom wall of the test cabin 1, a drain pipe (not shown) connected to the water outlet, and a valve (not shown) and other components. The drain pipe can be directly connected to the liquid recovery area or connected to a water pump (not shown). The specific setting and arrangement are not repeated here as the prior art.

[0054] For example, Figure 1 , 2As shown, the present invention takes the excavation of a cylindrical underground structure in a soil-rock composite stratum with three-layer soil characteristics as an example to introduce the excavation simulation process of the present invention: 1) According to the characteristics of the soil-rock composite stratum, three test soil bodies 100 with corresponding densities are prefabricated, and sensors such as pressure sensors, displacement sensors and strain sensors are set at key positions of components such as the cylindrical ground-connected wall model 2; 2) Three annular partition plates 5 are sequentially sleeved on the vertical guide shaft 4 and the test soil bodies 100 with three densities are filled and compacted layer by layer. At the same time, a predetermined amount of water or aqueous solution is injected into the peripheral pressure loading area 11. 3) Let it stand for a period of time so that the test soil 100 and the water or aqueous solution tend to be stable; 4) Calculate the size of the soil pressure at each position according to the engineering design data, and set the corresponding displacement-time curve for each jack 31 in the system; 5) Drain the water or aqueous solution in the peripheral pressure loading area 11 through the discharge system, so that the water level in the peripheral pressure loading area 11 gradually drops to a predetermined position; 6) Lift the uppermost annular partition plate 5 along the vertical guide shaft 4 to lift the annular partition plate 5 and the first layer of test soil 100 thereon out of the test soil area 20 to be excavated, so as to simulate the unloading effect of the soil during the excavation of the soil in the test soil area 20 to be excavated; 7) Repeat steps 5) and 6) until the water or aqueous solution in the peripheral pressure loading area 11 is completely discharged, and the three annular partition plates 5 and the three layers of test soil 100 thereon are lifted out of the test soil area 20 to be excavated, that is, a simulation test is completed. And the excavation simulation process is very convenient; at the same time, the external data acquisition system collects the data detected by each sensor for researchers to conduct detailed analysis and evaluation of the entire excavation process, providing a reliable reference for actual excavation projects.

[0055] It should be noted that the sensors and external data acquisition systems are prior art and well known to those skilled in the art, and the specific configuration and working principle of the sensors and data acquisition systems are not described in detail here. At the same time, how to process and analyze the collected data also belongs to the prior art, and is not described in detail here. The main purpose of the present invention is to simulate the excavation of a cylindrical underground structure and obtain corresponding data.

[0056] In addition, it should be noted that there are many implementation methods for preparing the test soil in the prior art, and the composition and preparation method of the test soil will not be described in detail here.

[0057] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A cylindrical underground structure excavation test device, characterized in that: include: A test chamber, wherein a containing space is defined inside the test chamber; The cylindrical ground-connected wall model is placed in the middle of the accommodation space, and the accommodation space is radially divided into a test soil area to be excavated and a peripheral pressure loading area; A vertical guide shaft, which is arranged in the middle of the test soil area to be excavated and forms a ring-shaped test soil filling space with the cylindrical ground-connected wall model; A plurality of annular partition plates, which are vertically movable and sleeved on the vertical guide shaft, and the annular partition plates are adapted to the test soil filling space to vertically divide the test soil filling space into a plurality of sub-filling areas, and a hanging portion for lifting and placing the annular partition plates is provided above the annular partition plates; and The peripheral pressure loading system is arranged in the peripheral pressure loading area and is used to apply pressure to the cylindrical ground-connected wall model from the outside to simulate the pressure generated by the peripheral soil on the cylindrical ground-connected wall model during excavation.

2. The cylindrical underground structure excavation test device according to claim 1, characterized in that: The peripheral pressure loading system comprises a plurality of jacks, which are distributed along the circumferential direction and / or axial direction of the cylindrical ground-connected wall model and abut against the outer wall of the cylindrical ground-connected wall model and the inner wall of the test chamber.

3. The cylindrical underground structure excavation test device according to claim 2, characterized in that: A plurality of groups of jacks are arranged axially along the cylindrical ground-connected wall model in the peripheral pressure loading area, and each group of jacks has a plurality of jacks distributed circumferentially along the cylindrical ground-connected wall model.

4. The cylindrical underground structure excavation test device according to claim 2, characterized in that: Pads are respectively arranged between the two ends of the jack and the cylindrical ground-connected wall model and the test cabin, and the jack is butted against the outer wall of the cylindrical ground-connected wall model and the inner wall of the test cabin through the pads.

5. The cylindrical underground structure excavation simulation device according to claim 2, characterized in that: It also includes multiple first support rods arranged on the outer wall of the test chamber and corresponding to the positions of the jacks, and a first diagonal support whose upper end is connected to the upper end of the first support rod. The lower end of the first support rod extends out of the bottom of the test chamber and is fixed to the ground, while the upper end extends out of the test chamber. The lower end of the first diagonal support is fixed to the ground.

6. The cylindrical underground structure excavation test device according to claim 1, characterized in that: Also included is a drain system for draining the water or aqueous solution contained in the peripheral pressure-loading zone.

7. The cylindrical underground structure excavation test device according to any one of claims 1 to 6, characterized in that: The inner edge of the annular partition plate is provided with a sleeve extending upwards, the guide sleeve can be vertically movably sleeved on the vertical guide shaft and is adapted to the vertical guide shaft, and the annular partition plate is arranged perpendicularly or obliquely to the axis of the sleeve.

8. A test method using the cylindrical underground structure excavation test device as claimed in any one of claims 1 to 7, characterized in that: Includes steps: S1. After the corresponding sensors are set on the test device, multiple annular partition plates are sequentially placed on the vertical guide shaft and filled with compacted test soil layer by layer; S2, driving the peripheral pressure loading system to apply a predetermined pressure to the cylindrical ground-connected wall model; S3. According to the predetermined excavation speed, the annular partition plates are lifted up along the vertical guide shaft from top to bottom at the hanging part, and the test soil accumulated on the annular partition plates are lifted out of the test soil area to be excavated, so as to simulate the unloading effect of the soil during the excavation of the test soil area to be excavated, until all the annular partition plates are lifted out of the test soil area to be excavated.

9. The test method according to claim 8, characterized in that: The step S2 of driving the peripheral pressure loading system to apply a predetermined pressure to the cylindrical ground-connected wall model includes a process of applying a predetermined pressure to the cylindrical ground-connected wall model on the outside by jacks distributed circumferentially and / or axially around the cylindrical ground-connected wall model.

10. The test method according to claim 8, characterized in that: The step S1 also includes a process of injecting a predetermined amount of water or aqueous solution into the peripheral pressure loading area; the step S3 also includes a process of discharging a predetermined amount of water or aqueous solution in the peripheral pressure loading area through a discharge system before lifting the annular partition plate each time, so as to lower the water level of the water or aqueous solution in the peripheral pressure loading area to a predetermined position.

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