Liquefied soft soil layer open cut tunnel anti-liquefaction structure

Abstract

The utility model discloses a liquefied soft soil layer open-cut tunnel anti-liquefaction structure which comprises tunnel enclosure walls symmetrically arranged in the length direction of a tunnel, and an open-cut tunnel is arranged between two tunnel enclosure walls. A plurality of cut-off walls are arranged below the open-cut tunnel, the two sides of each cut-off wall are fixedly connected with the inner wall of the tunnel enclosure wall, and the upper end of each cut-off wall is fixedly connected with the bottom of the open-cut tunnel. The utility model has the advantages of simple structure, low construction difficulty and low construction cost. According to the characteristics that the open-cut tunnel is long and large in scale, the cut-off walls are arranged at the bottom of the open-cut tunnel in a segmented mode, the influence of the liquefied stratum on the open-cut tunnel structure is reduced through the cut-off walls, compared with other schemes, the cut-off walls arranged at the bottom of the open-cut tunnel are good in economical efficiency, and the project investment cost is greatly saved.

Description

Technical Field

[0001] The utility model relates to the technical field of tunnel engineering, in particular to an anti-liquefaction structure of an open-cut tunnel in a liquefied soft soil layer. Background Art

[0002] As a fast construction method, the open-cut method is applicable to various geological conditions and is the most widely used in tunnel construction. In the process of open-cut tunnel construction, it is inevitable to cross liquefiable strata, which are prone to reduce or even lose strength under earthquake conditions. Soil liquefaction will cause large floating or sinking displacements in the open-cut tunnel, and the restraining effect of the soil around the underground structure will be reduced or lost, thus causing serious harm to the open-cut tunnel.

[0003] According to the "Standard for Seismic Design of Underground Structures" (GB / T 51336-2018), the liquefaction level of the site is divided into three categories: mild, moderate and severe. For moderate liquefaction sites, measures need to be taken to reduce the impact of liquefied strata on the structure. In moderate liquefied strata, measures such as liquefied soil cutoff, liquefied soil foundation treatment, and setting of structural pile foundation are generally adopted. Among them, liquefied soil cutoff is to set a cutoff wall on the outside of the structure, but the open-cut tunnel is generally long. If only the cutoff wall is set on the outside of the tunnel, the effect of reducing the liquefied stratum under the tunnel is poor; liquefied soil stratum treatment is to improve the properties of the liquefied stratum and transform it into a stratum that is not easy to liquefy. However, liquefied soil foundation treatment requires reinforcement of the strata under and around the tunnel. Considering the long length and large range of the tunnel, large-scale foundation reinforcement is required, which is costly and economical; setting of structural pile foundation also requires large-scale foundation reinforcement, which has the problem of high engineering investment cost and poor economy. Summary of the invention

[0004] The utility model aims to provide an anti-liquefaction structure for an open-cut tunnel in a liquefied soft soil layer, so as to solve the problems raised in the above-mentioned background technology.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A liquefaction-resistant structure for an open-cut tunnel in a liquefied soft soil layer comprises tunnel retaining walls symmetrically arranged along the length direction of the tunnel, wherein an open-cut tunnel is arranged between two tunnel retaining walls; a plurality of truncation walls are arranged below the open-cut tunnel, wherein both sides of the truncation walls are respectively fixedly connected to the inner walls of the tunnel retaining walls, and the upper ends of the truncation walls are fixedly connected to the bottom of the open-cut tunnel.

[0007] Preferably, the open-cut tunnel comprises tunnel side walls, a tunnel floor and a tunnel roof, wherein a tunnel partition wall is provided between the tunnel floor and the tunnel roof.

[0008] Preferably, the thickness of the truncation wall is 550-650 mm, wherein the height of the truncation wall is 1600-1800 mm.

[0009] Preferably, the cross-section of the truncation wall is rectangular or cross-shaped.

[0010] Preferably, the wall body of the truncation wall is a C30 concrete plain wall, wherein the top of the truncation wall is fixedly connected to the lower end of the tunnel floor, and the lower end of the truncation wall is downwardly arranged in the non-liquefied stratum.

[0011] Compared with the prior art, the utility model has the advantages of simple structure, low construction difficulty and low engineering cost. In view of the long length and large scale of the open-cut tunnel, a truncation wall is set at the bottom of the open-cut tunnel to reduce the influence of liquefied strata on the open-cut tunnel structure. Moreover, compared with other solutions, the truncation wall at the bottom of the open-cut tunnel is more economical, which greatly saves engineering investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a structural schematic diagram of the utility model;

[0013] Figure 2 It is a cross-sectional view of the structure of the utility model;

[0014] Figure 3 It is a structural schematic diagram of the truncation wall of the utility model.

[0015] Among them: 1. Tunnel retaining wall; 2. Open-cut tunnel; 201. Tunnel side wall; 202. Tunnel floor; 203. Tunnel roof; 204. Tunnel middle partition wall; 3. Cut-off wall. DETAILED DESCRIPTION

[0016] The utility model is further described in detail below in conjunction with the accompanying drawings.

[0017] Please refer to Figures 1 to 3 To achieve the above purpose, the utility model provides the following technical solutions:

[0018] A liquefied soft soil layer open-cut tunnel anti-liquefaction structure comprises a tunnel retaining wall 1 symmetrically arranged along the length direction of the tunnel, wherein an open-cut tunnel 2 is arranged between two tunnel retaining walls 1; a plurality of cut-off walls are arranged below the open-cut tunnel 2, wherein both sides of the cut-off walls are respectively fixedly connected to the inner wall of the tunnel retaining wall 1, and the upper end of the cut-off wall 3 is fixedly connected to the bottom of the open-cut tunnel 2; by arranging the cut-off wall 3 in sections at the bottom of the open-cut tunnel 2, the influence of the liquefied stratum on the structure of the open-cut tunnel 2 is reduced, thereby greatly improving the safety of the construction of the open-cut tunnel 2, and arranging the cut-off wall 3 at the bottom of the open-cut tunnel 2 is more economical than other solutions, thereby greatly saving the project investment cost.

[0019] See also Figure 2 As an embodiment of the utility model, the open-cut tunnel 2 includes a tunnel side wall 201, a tunnel floor 202 and a tunnel roof 203, wherein a tunnel partition wall 204 is provided between the tunnel floor 202 and the tunnel roof 203.

[0020] In the above-mentioned solution, the tunnel side wall 201 is fixedly connected to the tunnel enclosure wall 1, wherein the tunnel floor 202 is fixedly connected to the middle cut wall 3, so that the open-cut tunnel 2 has a strong stability.

[0021] Please refer to Figures 1 to 3 As an embodiment of the utility model, the wall of the truncation wall 3 is a C30 concrete plain wall, wherein the cross-section of the truncation wall 3 is rectangular or cross-shaped, and the stability of the truncation wall 3 is improved by adopting truncation walls 3 of different shapes; the thickness of the truncation wall 3 is 550-650 mm, wherein the height of the truncation wall is 1600-1800 mm; the top of the truncation wall 3 is fixedly connected to the lower end of the tunnel floor 202, wherein the lower end of the truncation wall 3 is downwardly arranged in the non-liquefied stratum.

[0022] In the above-mentioned scheme, in view of the long length and large scale of the open-cut tunnel 2, a tunnel retaining wall 1 is first set along the length direction of the tunnel, and then a cut-off wall 3 is constructed and installed between the two tunnel retaining walls 1, wherein the cut-off wall 3 extends downward into the non-liquefied stratum to a depth of 1500mm, and then the foundation pit of the open-cut tunnel 2 is excavated, and the open-cut tunnel 3 is constructed and installed above the cut-off wall 3; by setting a plurality of cut-off walls 3 at the bottom section of the open-cut tunnel 2, wherein the upper end of the cut-off wall 3 is fixedly connected to the bottom of the tunnel floor 202, and the lower end of the cut-off wall 3 is downwardly set in the non-liquefied stratum, so that a plurality of cut-off walls 3 form an anti-liquefaction structure under the open-cut tunnel 2, thereby greatly reducing the influence of the liquefied stratum on the structure of the open-cut tunnel 2, and improving the safety of the construction of the open-cut tunnel 2; compared with other schemes, the economical efficiency is good, and the engineering investment cost is greatly saved.

[0023] Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications fall within the protection scope of the present invention.

Claims

1. A liquefaction-resistant structure for an open-cut tunnel in a liquefied soft soil layer, characterized in that: The invention comprises tunnel retaining walls (1) symmetrically arranged along the length direction of the tunnel, wherein an open-cut tunnel (2) is arranged between two tunnel retaining walls (1); a plurality of cut-off walls (3) are arranged below the open-cut tunnel (2), wherein both sides of the cut-off walls (3) are respectively fixedly connected to the inner wall of the tunnel retaining walls (1), and the upper end of the cut-off wall (3) is fixedly connected to the bottom of the open-cut tunnel (2).

2. The anti-liquefaction structure of an open-cut tunnel in a liquefied soft soil layer according to claim 1, characterized in that: The open-cut tunnel (2) comprises a tunnel side wall (201), a tunnel floor (202) and a tunnel roof (203), wherein a tunnel partition wall (204) is provided between the tunnel floor (202) and the tunnel roof (203).

3. The anti-liquefaction structure of an open-cut tunnel in a liquefied soft soil layer according to claim 1, characterized in that: The thickness of the cut-off wall (3) is 550-650 mm, wherein the height of the cut-off wall (3) is 1600-1800 mm.

4. The anti-liquefaction structure of an open-cut tunnel in a liquefied soft soil layer according to claim 3, characterized in that: The cross section of the truncation wall (3) is rectangular or cross-shaped.

5. The anti-liquefaction structure of an open-cut tunnel in a liquefied soft soil layer according to claim 4, characterized in that: The wall body of the cut-off wall (3) is a C30 concrete plain wall, wherein the top of the cut-off wall (3) is fixedly connected to the lower end of the tunnel floor (202), and the lower end of the cut-off wall (3) is downwardly arranged in the non-liquefied stratum.

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