Tunnel toughness supporting structure and construction method thereof

Abstract

The tunnel tough supporting structure is used for excavating a tunnel through a drilling and blasting method, the tunnel tough supporting structure comprises one layer or two layers of primary supports which are attached to each other, each layer of primary support comprises a multi-ring primary support body, and the multi-ring primary support bodies are sequentially connected in the longitudinal direction of the tunnel; each ring of primary support body comprises a plurality of assembly type corrugated steel plate units, each assembly type corrugated steel plate unit is arc-shaped, and the plurality of assembly type corrugated steel plate units are sequentially connected to form a ring; each assembled corrugated steel plate unit is provided with a grouting hole; a waterproof sprayed concrete layer is sprayed on the inner side wall of the primary support on the inner side, the side attached to the tunnel surrounding rock is the outer side, and the side back to the tunnel surrounding rock is the inner side; and a basalt fiber ultra-high performance concrete layer is sprayed on the waterproof sprayed concrete layer. The supporting structure can give consideration to rigidity and toughness, and the disaster resistance and sustainability of tunnel engineering are improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of tunnel toughness support, and in particular relates to a tunnel toughness support structure and a construction method thereof. Background Art

[0002] In traditional tunnel construction, sprayed anchor steel arches or grid arches are often used for initial support. Their rigidity prevents the arches from effectively following large geological deformations, leading to stress concentration between the arches and the surrounding rock, thus increasing the stability risk of the tunnel project. The waterproofing layer or sheeting used is typically made of materials such as polyethylene film and rubber sheeting. These materials are difficult to install and difficult to unseal. Improper handling can easily lead to film damage, joint leaks, and other problems. Their durability is limited, and they are prone to aging, cracking, or deformation under prolonged use and the influence of the external environment, thus weakening the waterproofing effect.

[0003] Traditional support structures have limitations, including a lack of toughness, complex construction, and difficult maintenance. Rigid support structures are particularly susceptible to damage from external shocks, such as earthquakes and geological deformations, leading to safety risks and increased maintenance costs for tunnel projects. Therefore, a new type of resilient tunnel support structure is urgently needed. Summary of the Invention

[0004] The purpose of the present invention is to provide a tunnel toughness support structure and a construction method thereof, which can take into account both rigidity and toughness and improve the disaster resistance and sustainability of tunnel engineering.

[0005] The present invention adopts the following technical solution: a tunnel ductile support structure, which is used for tunnel excavation using the drill and blast method, comprising one or two layers of initial support, each layer of initial support comprising multiple rings of initial support bodies, which are sequentially connected in the longitudinal direction of the tunnel;

[0006] The primary support body of each ring includes multiple pieces of assembled corrugated steel plate units, each of which is arc-shaped and connected in sequence to form a ring; each piece of assembled corrugated steel plate unit is provided with a grouting hole;

[0007] A waterproof shotcrete layer is sprayed on the inner wall of the primary support, of which the side close to the tunnel surrounding rock is the outer side and the side facing away from the tunnel surrounding rock is the inner side;

[0008] A layer of ultra-high performance concrete with basalt fiber is sprayed on the waterproof sprayed concrete layer.

[0009] Furthermore, the thickness of the waterproof sprayed concrete layer is greater than the thickness of the waterproof board in traditional primary support.

[0010] Furthermore, the anti-basalt fiber ultra-high performance concrete layer is formed by solidifying the sprayed basalt fiber ultra-high performance concrete.

[0011] Furthermore, per cubic meter of basalt fiber ultra-high performance concrete, the following components are included by weight: 850 parts cement, 212.5 parts silica fume, 935 parts quartz sand, 255 parts quartz powder, 212.5 parts water, 21.25 parts high-performance water reducer, and 57 parts basalt fiber. The high-performance water reducer is a polycarboxylate-based high-efficiency water reducer with a solids content of 50%.

[0012] The present invention also discloses a construction method of the above-mentioned tunnel toughness support structure, comprising the following steps:

[0013] Step S1: Initial support construction:

[0014] After tunnel excavation using the drill-and-blast method, multiple prefabricated corrugated steel plate units are assembled into a ring around the tunnel surrounding rock in the same cross-section of the tunnel, forming the primary support body. Multiple rings of primary support bodies are assembled sequentially along the longitudinal direction of the tunnel to complete the construction of a layer of primary support suitable for surrounding rock grades I to III.

[0015] For the surrounding rock of grade IV to VI, apply a layer of primary support on the inner wall of the primary support suitable for the surrounding rock of grade I to III, and then apply another layer of primary support to form a two-layer structure of primary support, with the two layers of primary support fitting each other;

[0016] A cavity is formed between the initial support and the tunnel surrounding rock;

[0017] Step S2: Grouting behind the initial support:

[0018] Grouting is injected into the cavity through each grouting hole until the cavity between the assembled corrugated steel plate unit and the surrounding rock is dense;

[0019] Step S3: Waterproof layer construction:

[0020] Spray waterproof shotcrete on the inner wall of the primary support, solidify to form a waterproof shotcrete layer as a waterproof layer;

[0021] Step S4: Secondary lining construction:

[0022] A lining trolley is attached to the waterproof sprayed concrete layer to build the mold, and basalt fiber ultra-high performance concrete is poured. After solidification, a basalt fiber ultra-high performance concrete layer is formed as the secondary lining.

[0023] The present invention has the following beneficial effects: 1. Prefabricated corrugated steel plates are used to replace steel arches or lattice arches for initial support. Prefabricated corrugated steel plates require no welding, are quick to construct, and can achieve "quick closure," reducing environmental pollution within the tunnel. Furthermore, as a planar and ductile structure, they can disperse concentrated loads and achieve highly coordinated overall deformation. 2. Waterproof sprayed concrete is used to replace traditional waterproof membranes or waterproof boards. The waterproof sprayed concrete layer has a long lifespan and is not easily damaged, effectively reducing waterway blockage or water leakage caused by aging of the waterproof layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of a tunnel ductile support structure;

[0025] Among them: 1. Prefabricated corrugated steel plate unit; 2. Waterproof sprayed concrete layer; 3. Basalt fiber ultra-high performance concrete layer. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] The present invention discloses a tunnel toughness support structure, such as Figure 1 As shown, the drill-and-blast tunnel excavation method includes one or two layers of primary support, each layer of which includes multiple rings of primary support bodies, which are sequentially connected in the longitudinal direction of the tunnel. The longitudinal width of each ring of primary support bodies is generally 0.6 to 1.5 meters.

[0028] The primary support body of each ring includes multiple pieces of assembled corrugated steel plate units 1, each piece of the assembled corrugated steel plate units 1 is arc-shaped, and multiple pieces of the assembled corrugated steel plate units 1 are sequentially connected to form a ring; each piece of the assembled corrugated steel plate units 1 is provided with grouting holes; the assembled corrugated steel plate units 1 are all arc-shaped corrugated steel plates, and the height of the corrugated steel plate waves is determined according to the actual tunnel construction, and the distance between adjacent waves is determined according to the bearing capacity required for the initial support. If the required bearing capacity is large, the distance between adjacent waves is small; if the required bearing capacity is small, the distance between adjacent waves is large. The curvature of the corrugated steel plate is determined according to its location and is consistent with the curvature of the tunnel surrounding rock at its location.

[0029] For rock masses of grades I to III, one layer of primary support is laid; for rock masses of grades IV to VI, two layers of primary support are laid. For a single layer of primary support, a cavity is formed between the primary support and the tunnel surrounding rock. For a two-layer primary support structure, a cavity is formed between the primary support on the side closest to the tunnel surrounding rock and the tunnel surrounding rock.

[0030] A waterproof sprayed concrete layer 2 is sprayed on the inner wall of the initial support, wherein the side close to the tunnel surrounding rock is the outer side and the side facing away from the tunnel surrounding rock is the inner side.

[0031] A basalt fiber ultra-high performance concrete layer 3 is provided on the waterproof sprayed concrete layer 2; the basalt fiber ultra-high performance concrete layer 3 is formed by solidifying the sprayed basalt fiber ultra-high performance concrete.

[0032] The thickness of the arc-shaped corrugated steel plate is less than the thickness of the steel arch frame or grille arch frame used in traditional initial support. The thickness of the waterproof sprayed concrete layer 2 here is greater than the thickness of the waterproof board in traditional initial support. The thickness of the waterproof sprayed concrete layer 3 and the sum of the thickness of the assembled corrugated steel plate is equal to the thickness of the steel arch frame or grille arch frame and the waterproof board used in traditional initial support.

[0033] Basalt fiber ultra-high performance concrete contains the following components by weight per cubic meter: 850 parts cement, 212.5 parts silica fume, 935 parts quartz sand, 255 parts quartz powder, 212.5 parts water, 21.25 parts high-performance water reducer, and 57 parts basalt fiber. The high-performance water reducer is a polycarboxylate-based high-efficiency water reducer with a solids content of 50%.

[0034] The present invention also discloses a construction method of the above-mentioned tunnel toughness support structure, comprising the following steps:

[0035] Step S1: Initial support construction:

[0036] After the drill-and-blast tunnel is excavated, multiple prefabricated corrugated steel plate units 1 are assembled into a ring around the tunnel surrounding rock in the same cross section of the tunnel to form the primary support body. Multiple rings of the primary support body are assembled sequentially along the longitudinal direction of the tunnel to complete the construction of a layer of primary support suitable for surrounding rock grades I to III.

[0037] For the surrounding rock of grade IV to VI, apply a layer of primary support on the inner wall of the primary support suitable for the surrounding rock of grade I to III, and then apply another layer of primary support to form a two-layer structure of primary support, with the two layers of primary support fitting each other;

[0038] A cavity is formed between the initial support and the tunnel surrounding rock.

[0039] Step S2: Grouting behind the initial support:

[0040] Grouting is injected into the cavity through each of the grouting holes to make the cavity between the assembled corrugated steel plate unit 1 and the surrounding rock dense.

[0041] Step S3: Waterproof layer construction:

[0042] Waterproof shotcrete is sprayed onto the inner wall of the primary support, which solidifies to form a waterproof shotcrete layer 2, which serves as a waterproof layer, replacing the waterproof board between the primary support and the secondary lining. The waterproof shotcrete layer 2 is long-lasting and resistant to damage, effectively reducing waterway blockages and water leakage caused by the aging of the waterproof layer.

[0043] Step S4: Secondary lining construction:

[0044] A lining trolley is attached to the waterproof sprayed concrete layer 2 to build a mold, and basalt fiber ultra-high performance concrete is poured. After solidification, a basalt fiber ultra-high performance concrete layer 3 is formed as the secondary lining.

[0045] The secondary lining is constructed from basalt fiber ultra-high performance concrete, which offers greater bearing capacity and durability than conventional concrete. The combined support structure, formed by prefabricated corrugated steel plate primary support, a waterproof sprayed concrete layer, and a secondary lining of basalt fiber ultra-high performance concrete, is extremely resilient.

Claims

1. A tunnel ductile support structure, characterized in that: It is used for tunnel excavation using the drill and blast method and comprises one or two layers of primary support, each layer of the primary support comprising multiple rings of primary support bodies, which are sequentially connected in the longitudinal direction of the tunnel; The initial support body of each ring comprises a plurality of assembled corrugated steel plate units (1), each of the assembled corrugated steel plate units (1) is arc-shaped, and the plurality of assembled corrugated steel plate units (1) are sequentially connected to form a ring; each of the assembled corrugated steel plate units (1) is provided with a grouting hole; A waterproof sprayed concrete layer (2) is sprayed on the inner side wall of the initial support, wherein the side close to the tunnel surrounding rock is the outer side and the side facing away from the tunnel surrounding rock is the inner side; A basalt fiber ultra-high performance concrete layer (3) is sprayed onto the waterproof sprayed concrete layer (2).

2. A tunnel toughness support structure according to claim 1, characterized in that: The thickness of the waterproof sprayed concrete layer (2) is greater than the thickness of the waterproof board in traditional initial support.

3. A tunnel toughness support structure according to claim 2, characterized in that: The basalt fiber ultra-high performance concrete layer (3) is formed by solidifying the sprayed basalt fiber ultra-high performance concrete.

4. A tunnel toughness support structure according to claim 3, characterized in that: The basalt fiber ultra-high performance concrete contains the following components by weight per cubic meter: 850 parts cement, 212.5 parts silica fume, 935 parts quartz sand, 255 parts quartz powder, 212.5 parts water, 21.25 parts high-performance water reducer, and 57 parts basalt fiber. The high-performance water reducer is a polycarboxylate-based high-efficiency water reducer with a solids content of 50%.

5. A construction method for a tunnel toughness support structure according to any one of claims 1 to 4, characterized in that: The steps include: Step S1: Initial support construction: After the tunnel is excavated using the drill-and-blast method, multiple assembled corrugated steel plate units (1) are assembled into a ring around the tunnel surrounding rock in the same cross section of the tunnel to form an initial support body; multiple rings of the initial support body are assembled in sequence along the longitudinal direction of the tunnel to complete the construction of a layer of initial support suitable for surrounding rock of grades I to III; For the surrounding rock of grade IV to VI, apply a layer of primary support on the inner wall of the primary support suitable for the surrounding rock of grade I to III, and then apply another layer of primary support to form a two-layer structure of primary support, with the two layers of primary support fitting each other; A cavity is formed between the initial support and the tunnel surrounding rock; Step S2: Grouting behind the initial support: Grouting is injected into the cavity through each grouting hole until the cavity between the assembled corrugated steel plate unit (1) and the surrounding rock is dense; Step S3: Waterproof layer construction: Spraying waterproof shotcrete on the inner wall of the primary support, solidifying to form a waterproof shotcrete layer (2) as a waterproof layer; Step S4: Secondary lining construction: A lining trolley is attached to the waterproof sprayed concrete layer (3) to form a mold, and basalt fiber ultra-high performance concrete is poured. After solidification, a basalt fiber ultra-high performance concrete layer (3) is formed as a secondary lining.

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