A centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall

Abstract

This utility model relates to the field of physical simulation in geotechnical engineering, and in particular to a centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall. It includes a centrifuge model box, a model tunnel, and an isolation wall. The centrifuge model box is a cuboid box with four sides, including a bottom plate and a left side plate, a rear side plate, and a right side plate connected to the bottom plate. The left side plate, rear side plate, and right side plate are connected sequentially. A transparent side plate serves as the front side plate and is detachably connected to the front opening of the centrifuge model box via bolts. The model tunnel is arranged along the front-back direction. The isolation wall consists of several isolation piles spaced apart along the front-back direction. An external baffle is located on the upper circumferential side and is detachably connected to the surrounding side plates. The external baffle has through holes. This centrifuge test device can accurately reproduce the soil properties around the embedded isolation wall, avoiding the disturbance to the soil layer caused by traditional insertion methods, thus achieving precise simulation of the isolation wall deformation response caused by tunnel construction.

Description

Technical Field

[0001] This utility model relates to the field of physical simulation in geotechnical engineering, and in particular to a centrifugal test device for simulating the interaction between a tunnel and an embedded isolation wall. Background Technology

[0002] With rapid urbanization, available surface space in cities is becoming increasingly scarce, leading to the large-scale development and utilization of underground space, particularly tunnels. In urban areas with dense surface buildings and extensive underground structures and infrastructure, tunnel boring machines (TBMs) are widely used for tunnel construction. Despite the rapid advancements in TBM construction technology, large-scale ground subsidence and even collapses still occur when encountering special geological conditions or due to operational errors. Therefore, studying the mechanism by which embedded retaining walls protect against soil responses induced during tunnel construction and predicting and assessing building deformation has significant engineering value.

[0003] Assessing the impact of tunnel construction on the deformation of adjacent structures is crucial throughout the design and construction phases of tunnel engineering. In the design phase, evaluating the protective effect of embedded retaining walls on tunnel construction can help optimize the tunnel route, thereby avoiding adverse environmental impacts during construction. During shield tunnel construction, special geological conditions or operational errors can easily lead to deformation and damage to surrounding structures. Evaluating the protective effect of retaining walls under various parameters is essential to preventing damage to buildings and loss of life and property. However, accurately assessing the protective effect of embedded retaining walls against tunnel construction-induced soil responses still faces many challenges, such as complex soil characteristics, highly nonlinear soil-structure interaction mechanisms, and the impact of various retaining wall lengths and materials on protective effectiveness.

[0004] Currently, there are three main methods for studying the interaction mechanism between embedded retaining walls and the surrounding soil of tunnels. The first is numerical simulation or simplified theoretical calculation, which, while low-cost, has relatively low reliability. The second is field measurement or full-scale testing, which can consider complex factors and obtain accurate results; however, the research cost is high, and large-scale prediction and evaluation are not feasible. Physical model testing provides a more reliable research method, allowing for a more accurate study of the protective effect of retaining walls on buildings surrounding the tunnel construction area. To further improve the accuracy of model tests, centrifuge model tests using hypergravity environments to simulate real soil stress have gained widespread acceptance. Because the gravitational acceleration of the entire model box needs to be increased to tens or even hundreds of times that of conventional Earth's gravitational acceleration, centrifuge model test boxes are generally small, and the dimensions of various models inside the box are also small. This presents significant challenges to model fabrication and test preparation.

[0005] The method of studying the interaction mechanism between tunnels and embedded retaining walls using centrifugal model tests generally considers a two-dimensional plane strain model, and then uses particle image velocimetry to collect experimental data through a transparent window on one side. To simulate the properties of a homogeneous soil layer, researchers used a sand-sprinkling method to prepare sand samples, that is, dropping sand at a constant speed from a certain height into the model box. Therefore, in the two-dimensional plane strain model, the model box needs to be placed upside down to ensure that the plane strain tunnel model or building model is parallel to the direction of sand falling (i.e., vertically downward). At the same time, a partition is needed to temporarily support the top of the model box on one side, which is the top position of the sand sample when the model box is placed vertically. For related structures located on the ground, such as raft foundation building models, the building model can be placed directly on top of the soil layer after the sand sample is prepared and the model box is placed vertically. However, for embedded structures such as retaining walls, there is currently no effective centrifugal model test device and preparation method. Existing studies typically involve pressing the isolation wall structure into a specified depth above a prepared sand sample; however, this method cannot simulate the properties of the uniform soil layer around the isolation wall, thus affecting the accuracy of the model test results. Utility Model Content

[0006] To address the aforementioned technical problems, this utility model proposes a centrifugal test device for simulating the interaction between a tunnel and an embedded isolation wall, comprising a centrifugal model box, a model tunnel, and an isolation wall. The centrifugal model box is a cuboid box with four sides, including a bottom plate and a left side plate, a rear side plate, and a right side plate connected to the bottom plate. The left side plate, the rear side plate, and the right side plate are connected sequentially. A transparent side plate is used as the front side plate and is detachably connected to the front opening of the centrifugal model box by bolts. The model tunnel is arranged along the front-back direction. The isolation wall consists of several isolation piles spaced apart along the front-back direction, and the isolation wall is spaced a certain distance from the model tunnel in the left-right direction.

[0007] Preferably, a circular protrusion with an outer diameter matching the inner diameter of the model tunnel is provided on the rear side plate, or a circular groove with an inner diameter matching the outer diameter of the model tunnel is provided on the rear side plate.

[0008] Preferably, the sample also includes a sand sample, which is placed in a box with an upper opening consisting of a centrifuge model box and a transparent side plate and filled to a certain height; the model tunnel is located in the sand sample and at a certain distance from the bottom plate.

[0009] Preferably, the isolation wall is arranged in the front-to-back direction, with most of the isolation wall buried in the sand sample in terms of height, a certain height of the top exposed above the sand sample, and a certain distance between the bottom and the base plate.

[0010] Preferably, it also includes an external baffle, which is disposed on the upper surface of the sand sample and is detachably connected to the surrounding side plates in the circumferential direction. The external baffle is provided with a through hole for the isolation pile to pass through.

[0011] Preferably, the outer baffle is detachably connected to the surrounding side panels circumferentially by foam tape.

[0012] This utility model has the following innovative features:

[0013] 1. This utility model breaks through the technical bottleneck of existing centrifugal model test technology being unable to realize the arrangement of embedded isolation walls in uniform soil layers. It can accurately reproduce the soil properties around the embedded isolation wall structure, avoid the disturbance of the soil layer caused by the traditional insertion method, and thus achieve the protective effect of accurately simulating the response of the embedded isolation wall to soil disturbance induced by tunnel construction.

[0014] 2. The centrifugal testing device of this utility model ensures that the overall design is reasonable, simple and easy to operate, while achieving uniform soil layer arrangement, and will not affect the stability and strength of the embedded isolation wall structure.

[0015] 3. This utility model adjusts the position of the embedded isolation wall by using an external baffle. Holes are drilled on the external baffle according to the designed pile spacing of the isolation piles to ensure that the isolation piles are inserted into the correct position without disturbing the soil (the sand is used to simulate the soil) during the sand spreading process. This method is also applicable to the preparation of centrifuge tests related to the isolation wall.

[0016] 4. This utility model reduces the excessive reinforcement requirements of isolation piles caused by soil disturbance due to traditional insertion methods by precisely controlling the insertion position of the isolation piles and uniformly distributing sand, thus avoiding material waste; moreover, centrifugation tests can efficiently simulate various parameters and optimize the design of isolation pile body length, spacing, etc., indirectly reducing material consumption. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the first state of the centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall according to this utility model;

[0018] Figure 2 This is a schematic diagram of the second state of the centrifugal test device for simulating the interaction between a tunnel and an embedded isolation wall according to this utility model;

[0019] Figure 3 This is a schematic diagram of the preparation process of the centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall according to this utility model;

[0020] In the diagram: 1. Centrifuge model box; 2. Model tunnel; 3. Sand sample; 4. Isolation wall; 5. External baffle; 6. Foam tape; 7. Transparent side panel; 8. Bolt. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific working methods.

[0022] like Figure 1-2 As shown, this utility model proposes a centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall, including a centrifuge model box 1, a model tunnel 2, a sand sample 3, and an isolation wall 4; the centrifuge model box 1 is a cuboid box with four sides, including a bottom plate and a left side plate, a rear side plate, and a right side plate connected to the bottom plate. The left side plate, the rear side plate, and the right side plate are connected in sequence. A transparent side plate 7 is used as the front side plate and is detachably connected to the front opening of the centrifuge model box 1 by bolts 8.

[0023] The sand sample 3 is placed in the top-opening box consisting of the centrifuge model box 1 and the transparent side plate 7 and filled to a certain height; the model tunnel 2 is arranged in the front-back direction, located in the sand sample 3 and at a certain distance from the bottom plate. A circular protrusion with an outer diameter consistent with the inner diameter of the model tunnel 2 can be set on the rear side plate, or a circular groove with an inner diameter consistent with the outer diameter of the model tunnel 2 can be set on the rear side plate.

[0024] The isolation wall 4 is composed of several isolation piles spaced apart in the front-back direction. That is, the isolation wall formed by the isolation piles is arranged in the front-back direction (parallel to the left side plate and the right side plate). In terms of height, most of the isolation wall 4 / isolation piles are buried in the sand sample 3, with the top of the sand sample 3 exposed at a certain height, and the bottom is a certain distance away from the bottom plate. The isolation wall 4 / isolation piles are spaced a certain distance from the model tunnel 2 in the left-right direction.

[0025] It also includes an external baffle 5 and foam tape 6. The external baffle 5 can be placed on the sand sample 3 and is connected to the surrounding side plates in the circumferential direction by the foam tape 6. The external baffle 5 is provided with a through hole for the isolation pile to pass through.

[0026] like Figure 3 The following is the preparation process of the centrifuge test device for simulating the interaction between a tunnel and an embedded isolation wall according to this utility model: a. Connect the external baffle 5 to the rear side plate, left side plate and right side plate of the centrifuge model box 1 with foam tape 6. The connection position is located at the required laying height of the sand sample 3; lay the centrifuge model box 1 flat on the ground; place the model tunnel 2 vertically in the set position.

[0027] b. The sand sample 3 is uniformly and evenly sprinkled into the centrifuge model box 1 from a certain height by the sand sprinkling method. Whenever the sand sample 3 reaches the through hole on the outer baffle 5, the sand sprinkling is paused and an isolation pile is inserted. Then the sand sprinkling continues until all the isolation piles are inserted and the sand sample 3 reaches the installation position of the transparent side plate 7.

[0028] c. Use tools to level the outer surface of the sand sample 3, and then fix the transparent front window 7 onto the centrifuge model box 1 with bolts 8;

[0029] d. Position centrifuge model box 1 so that its bottom plate is flat on the ground;

[0030] e. Then remove the outer baffle 5 and the foam tape 6.

[0031] Centrifuge test apparatus was placed on a centrifuge to conduct centrifuge model tests to study the impact of tunnel construction on embedded isolation walls.

[0032] Although the present invention has been described above with reference to preferred embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of this invention shall be determined by the claims.

Claims

1. A centrifuge test apparatus for simulating the interaction of a tunnel with a buried barrier wall, characterised in that, The system includes a centrifuge model box, a model tunnel, an isolation wall, and an external baffle. The centrifuge model box is a cuboid box with four sides, including a bottom plate and a left side plate, a rear side plate, and a right side plate connected to the bottom plate. The left side plate, the rear side plate, and the right side plate are connected sequentially. A transparent side plate is used as the front side plate and is detachably connected to the front opening of the centrifuge model box by bolts. The model tunnel is arranged along the front-back direction. The isolation wall consists of several isolation piles spaced apart along the front-back direction. The isolation wall is spaced a certain distance from the model tunnel in the left-right direction. The external baffle is located at the top and is detachably connected to the surrounding side plates in the circumferential direction. The external baffle has through holes for the isolation piles to pass through.

2. The centrifugal test device of claim 1, wherein, A circular protrusion with an outer diameter matching the inner diameter of the model tunnel is provided on the rear side plate, or a circular groove with an inner diameter matching the outer diameter of the model tunnel is provided on the rear side plate.

3. The centrifugal test device according to claim 1 or 2, characterized in that It also includes a sand sample, which is placed in a box with an upper opening, consisting of a centrifuge model box and a transparent side plate, and filled to a certain height; the model tunnel is located in the sand sample and at a certain distance from the bottom plate.

4. The centrifugal test device of claim 3, wherein, The isolation wall is arranged in the front-to-back direction. In terms of height, most of the isolation wall is buried in the sand sample, with a certain height of the top exposed above the sand sample, and the bottom is a certain distance away from the base plate.

5. The centrifugal test device of claim 4, wherein, The external baffle is placed on the upper surface of the sand sample.

6. The centrifugal test device of claim 5, wherein, The outer baffle is detachably connected to the surrounding side panels circumferentially via foam tape.

Images