A construction method for tunnel seismic isolation structure

Abstract

The present invention belongs to the field of seismic isolation technology, and specifically relates to a construction method for a tunnel seismic isolation structure. The steps include the installation of an arch wall seismic isolation structure and the installation of an inverted arch seismic isolation structure, wherein the construction process of the arch wall seismic isolation structure includes, from the inside to the outside, an initial support structure, a rubber seismic isolation cushion fixed by expansion bolts, a waterproof layer, and a secondary lining structure; the construction of the inverted arch seismic isolation structure includes, from the inside to the outside, an initial support structure, a cement mortar leveling layer, a composite seismic isolation cushion composed of a polyurethane foam board and a rubber seismic isolation bearing, a water stop layer, and an inverted arch concrete layer. The construction method of the tunnel seismic isolation structure is easy to operate, saves manpower and material resources, and has a relatively low cost. Its installed molding structure has the characteristics of being able to effectively absorb seismic wave energy and avoid damage to the overall structure of the tunnel.

Description

Technical Field

[0001] The invention belongs to the technical field of seismic reduction and isolation, and specifically relates to a construction method of a tunnel seismic isolation structure. Background Art

[0002] People have always felt that tunnel structures have good seismic performance. However, post-earthquake surveys of the Kobe earthquake in Japan, the Chichi earthquake in Taiwan, China, the Wenchuan earthquake in Sichuan, China, and the recent Qinghai earthquake have found that the seismic isolation technology in tunnel structures is not ideal and even poses a major safety hazard. Tunnel construction is generally a control project. Once damaged, it will cause traffic congestion until the entire line is paralyzed, which is not conducive to post-disaster rescue. Therefore, there is a strong demand for seismic isolation design, and the importance of safety is self-evident.

[0003] At present, there is no complete design theory for tunnel seismic isolation, and the complete set of effective measures in reality is also very limited. The invention with patent number CN202110830002.3 discloses a tunnel with high seismic isolation performance and its manufacturing method, whose structure includes a waterproof layer, an outer lining, a shock-absorbing layer and an inner lining. The waterproof layer, the outer lining, the shock-absorbing layer and the inner lining are all circular structures. The waterproof layer is composed of an asphalt layer and a waterproof board. The asphalt layer covers the waterproof board. One side of the asphalt layer is in contact with the waterproof board, and the other side is connected to the surrounding rock. The outer lining is a concrete structure. Several anchor rods are inserted in the outer lining. One end of the anchor rod is inserted into the outer lining, and the other end passes through the waterproof layer and is embedded in the surrounding rock. The shock-absorbing layer is a foam concrete structure. The inner lining is composed of multiple arc-shaped segments. The shock-absorbing layer connects the outer lining and the inner lining. This invention can first achieve a strength enhancement and preliminary shock absorption effect on the outer lining structure, and ensure the performance of the weak earthquake resistance area of ​​the tunnel, and then through the shock absorption layer, it can achieve the overall improvement of the tunnel strength and earthquake resistance to ensure its safety. However, its structure has problems such as complex construction, difficult construction, limited effect on seismic isolation and protection, high construction cost, and poor economy. Summary of the invention

[0004] The purpose of the present invention is to provide a construction method for a tunnel seismic isolation structure with simple structure, convenient construction, long-term and stable seismic isolation effect, low engineering cost and good economic benefits.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for constructing a tunnel seismic isolation structure, comprising the construction of an inverted arch seismic isolation structure and the construction of an arch wall seismic isolation structure, characterized in that:

[0007] The inverted arch seismic isolation structure construction process comprises the following steps:

[0008] A. Preparation of arch seismic isolation materials and initial support base surface treatment: prepare rubber seismic isolation bearings and polyurethane foam boards for arch seismic isolation structures; cut off exposed anchor heads and steel bar heads and other protrusions on the initial support base surface, and sprinkle water to soak them;

[0009] B. Cement mortar leveling: scrape and apply cement mortar and smooth it, sprinkle water to cover and maintain;

[0010] C. Arrange the polyurethane foam board and rubber seismic isolation bearing: Arrange the polyurethane foam board evenly at the bottom of the invert, and then embed the rubber seismic isolation bearing into the circular frame on the surface of the polyurethane foam board;

[0011] D. Waterstop construction: fix the longitudinal blind pipe, reserve the annular blind pipe and construct the waterproof membrane according to the design requirements;

[0012] E. Casting the invert arch: tying the invert arch reinforcement and casting the invert arch concrete;

[0013] The arch wall seismic isolation structure construction process comprises the following steps:

[0014] a. Preparation of arch wall seismic isolation materials and initial support base surface treatment: cut off the exposed anchor heads and steel bar heads and other protrusions on the initial support base surface, and sprinkle water to soak;

[0015] b. Cement slurry leveling: Apply cement mortar and smooth it, sprinkle water to cover and maintain;

[0016] c. Arrange rubber seismic isolation pads: Use expansion bolts to evenly fix the rubber seismic isolation pads on the arch wall;

[0017] d. Waterproof layer construction: Fix the annular blind pipe and waterproof membrane according to the design requirements. When fixing the geotextile, the steel nail gasket is arranged between the adjacent bosses of the rubber isolation pad;

[0018] e. Pouring of secondary lining: The lining trolley is put into place and the secondary lining concrete is poured.

[0019] Additional technical features of the above-mentioned tunnel seismic isolation structure construction method also include:

[0020] - In the cement slurry leveling process of step B or step b, after curing is completed, the flatness should meet the depth-to-length ratio between the two protrusions of D / L≤1 / 30;

[0021] In step c, the rubber seismic isolation pad has a plurality of bosses arranged side by side, the bosses face the waterproof layer, and the back of the rubber seismic isolation pad is in close contact with the initial support base surface and is fixed thereto by expansion bolts;

[0022] ——During the construction process, the installation gaps between the rubber isolation pads, between the rubber isolation supports and the polyurethane foam boards, and between the polyurethane foam boards can be controlled within the range of 5 to 10 mm.

[0023] The beneficial effects of the present invention are as follows: the structure can effectively absorb seismic wave energy through the rubber seismic isolation pad layer of the arch wall seismic isolation structure and the composite seismic isolation pad layer composed of a polyurethane foam board and a rubber seismic isolation support of the inverted arch seismic isolation structure, and buffer the multi-directional impact of the earthquake at intervals, thereby avoiding damage to the overall structure of the tunnel; and the tunnel seismic isolation composite structure obtained by the construction method is simple, quick and convenient to operate, has a low construction cost and outstanding economic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of a tunnel seismic isolation structure according to the present invention;

[0025] Figure 2 for Figure 1 Structural schematic diagram of part a of the middle arch wall seismic isolation structure;

[0026] Figure 3 for Figure 1 Structural diagram of part b of the middle arch seismic isolation structure

[0027] Figure 4 It is a schematic diagram of the flow chart of the construction method of the seismic isolation structure of the tunnel. DETAILED DESCRIPTION

[0028] The construction method and working principle of a tunnel seismic isolation structure provided by the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0029] See also Figures 1 to 3 , which is a schematic diagram of a tunnel seismic isolation structure provided by the present invention. The tunnel seismic isolation structure comprises an arch wall seismic isolation structure a and an inverted arch seismic isolation structure b, wherein the arch wall seismic isolation structure a comprises, from inside to outside, an initial support structure 1, a rubber seismic isolation cushion layer 2 fixed by expansion bolts 10, a waterproof layer 3 and a secondary lining structure 4; the inverted arch seismic isolation structure b comprises, from inside to outside, an initial support structure 5, a cement mortar leveling layer 6, a composite seismic isolation cushion layer 7 composed of a polyurethane foam board 71 and a rubber seismic isolation bearing 72, a water stop layer 8 and an inverted arch concrete layer 9.

[0030] like Figure 4 As shown, the construction process includes the following main steps:

[0031] The construction process of the inverted arch seismic isolation structure b comprises the following steps:

[0032] A. Preparation of inverted arch seismic isolation materials and treatment of the base surface of the early support structure 5: prepare rubber seismic isolation bearings 72 and polyurethane foam boards 71 ​​used in the inverted arch seismic isolation structure b; cut off the exposed anchor heads and steel bar heads and other protrusions on the base surface of the early support structure 5, and sprinkle water to soak them;

[0033] B. Cement mortar leveling: scrape and apply cement mortar and smooth it, sprinkle water to cover and maintain;

[0034] C. Arrange the polyurethane foam board 71 and the rubber seismic isolation support 72: Arrange the polyurethane foam board evenly at the bottom of the invert, and then embed the rubber seismic isolation support 72 into the return frame 711 on the surface of the polyurethane foam board 71;

[0035] D. Construction of water stop layer 8: fix the longitudinal blind pipe, reserve the annular blind pipe and construct the waterproof membrane according to the design requirements;

[0036] E. Casting the inverted arch: tying the inverted arch reinforcement and casting the inverted arch concrete layer 9;

[0037] The construction process of the arch wall seismic isolation structure a comprises the following steps:

[0038] a. Preparation of arch wall seismic isolation materials and treatment of initial support base surface: Cut off the exposed anchor heads, steel bar heads and other protrusions on the base surface of the initial support structure 1, and sprinkle water to soak them.

[0039] b. Cement slurry leveling: Apply cement mortar and smooth it, sprinkle water to cover and maintain;

[0040] c. Arrange the rubber seismic isolation pad 2: Use expansion bolts 10 to evenly fix the rubber seismic isolation pad on the arch wall;

[0041] d. Construction of waterproof layer 3: Fix the annular blind pipe and waterproof membrane according to the design requirements. When fixing the geotextile, the steel nail gasket is arranged between the adjacent bosses of the rubber isolation pad;

[0042] e. Casting of secondary lining structure 4: The lining trolley is put in place and the secondary lining concrete is cast.

[0043] Its working principle is as follows: the seismic isolation structure of the tunnel is provided with seismic isolation structures at the arch wall and the invert arch, which is composed of a rubber seismic isolation pad 2 or a composite seismic isolation pad 7 composed of a polyurethane foam board 71 and a rubber seismic isolation support 72. On the basis of the original internal structure of the tunnel, the seismic isolation capacity of the overall tunnel structure is improved through rubber buffering and shock absorption. The seismic isolation structure can effectively absorb the energy of seismic waves and minimize the impact of seismic shock on concrete. In addition, the seismic isolation structure is simple in structure, convenient in construction, and relatively low in cost.

[0044] In the construction of the above-mentioned new tunnel seismic isolation structure,

[0045] In the cement slurry leveling process of step B or step b, after curing is completed, the flatness should meet the depth-to-length ratio between the two protrusions D / L≤1 / 30;

[0046] ——In order to enhance the ability of buffering shock and absorbing impact, in step c, a plurality of bosses 21 are arranged side by side on the rubber isolation pad, which are evenly distributed along the width direction of its cross section, that is, an internal deformation structure is formed, which can absorb and reduce vibration energy; the bosses 21 face the waterproof layer, and the back side of the rubber isolation pad layer 2 is in close contact with the base surface of the initial support structure 1 and is fixed to it through expansion bolts 10;

[0047] ——During the construction process, the installation gaps between the rubber isolation pads 2 and the rubber isolation pads 2, between the rubber isolation bearings 72 and the polyurethane foam boards 71, and between the polyurethane foam boards 71 ​​and the polyurethane foam boards 71 ​​can be controlled within a range of 5 to 10 mm;

[0048] - Further, the cross-sectional shape of the boss 21 on the surface of the rubber isolation pad 2 is trapezoidal, rectangular, conical, circular or a combination of multiple shapes, and the rubber isolation support 72 is composed of a rubber matrix and one or more layers of stiffening steel plates disposed inside the rubber matrix;

[0049] The rubber matrix of the rubber isolation pad 2 and the rubber isolation support 72 includes but is not limited to natural rubber, chloroprene rubber, EPDM rubber, nitrile rubber and polyurethane rubber and a mixture of two or more thereof;

[0050] Preferably, the composite seismic isolation cushion layer 7 comprises a polyurethane foam board 71 with a plurality of Chinese characters 711 distributed on the surface, and the rubber seismic isolation support 72 is embedded in the Chinese characters 711, and the top surface height of the rubber seismic isolation support 72 is not lower than the surface height of the polyurethane foam board 71;

[0051] During production, since the rubber seismic isolation bearing 72 is arranged at the bottom of the inverted arch and is not maintainable, its ozone aging performance is improved by 1 to 2 times compared with that of ordinary bridge plate rubber bearings;

[0052] In addition, the rubber seismic isolation bearing 72 is arranged at the bottom of the invert arch. Considering the risk of it being soaked in water, two performance requirements are added to it: constant compression permanent deformation and alkali resistance after water soaking, and the performance is higher than that of ordinary bridge plate rubber bearings.

Claims

1. A method for constructing a tunnel seismic isolation structure, comprising the construction of an inverted arch seismic isolation structure and the construction of an arch wall seismic isolation structure, characterized in that: The construction process of the inverted arch seismic isolation structure comprises the following steps: A. Preparation of arch seismic isolation materials and treatment of initial support base surface: prepare rubber seismic isolation bearings and polyurethane foam boards for arch seismic isolation structure; cut off the exposed anchor heads and steel bar heads on the initial support base surface, and sprinkle water to soak them; B. Cement mortar leveling: scrape and apply cement mortar and smooth it, sprinkle water to cover and maintain; C. Arrange the polyurethane foam board and rubber seismic isolation bearing: Arrange the polyurethane foam board evenly at the bottom of the invert, and then embed the rubber seismic isolation bearing into the circular frame on the surface of the polyurethane foam board; D. Waterstop construction: fix the longitudinal blind pipe, reserve the annular blind pipe and construct the waterproof membrane according to the design requirements; E. Casting the inverted arch: tying the inverted arch reinforcement and casting the inverted arch concrete; The arch wall seismic isolation structure construction process comprises the following steps: a. Preparation of arch wall seismic isolation materials and treatment of initial support base surface: cut off the exposed anchor heads and steel bar heads on the initial support base surface, and sprinkle water to soak them; b. Cement slurry leveling: Apply cement mortar and smooth it, sprinkle water to cover and maintain; c. Arrange rubber seismic isolation pads: Use expansion bolts to evenly fix the rubber seismic isolation pads on the arch wall; d. Waterproof layer construction: Carry out annular blind pipe fixation and waterproof membrane construction according to design requirements. When fixing geotextile, steel nail gaskets are arranged between adjacent bosses of rubber seismic isolation pads; e. Casting of secondary lining: The lining trolley is in place and the secondary lining concrete is cast; In step c, the rubber isolation pad has a plurality of bosses arranged side by side, the bosses face the waterproof layer, and the back of the rubber isolation pad is in close contact with the initial support base surface and is fixed thereto by expansion bolts.

2. The construction method of a tunnel seismic isolation structure according to claim 1, characterized in that: In the cement slurry leveling process of step B or step b, after curing is completed, the flatness should meet the depth-to-length ratio between the two protrusions of D / L≤1 / 30.

3. The construction method of a tunnel seismic isolation structure according to claim 1, characterized in that: During the construction process, the installation gaps between the rubber isolation pads, between the rubber isolation supports and the polyurethane foam boards, and between the polyurethane foam boards are controlled to be between 5 and 10 mm.

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