Subway segment reinforcing system based on profile steel and high-ductility fiber reinforced cement-based composite material combination

Abstract

The invention provides a subway segment reinforcing system based on a profile steel and high-ductility fiber reinforced cement-based composite material combination. The system is formed by combining a space framework structure composed of profile steel, a high-ductility fiber reinforced cement-based composite material layer poured into a framework, and a chemical anchor bolt system for connecting segments and the framework. The section steel with different sizes is selected according to the deformation degree of the existing duct piece, the chemical anchor bolt is matched according to the specification of the section steel, and the implantation depth is standardized. The high-ductility fiber reinforced cement-based composite material has the advantages of high strength increase speed, high construction speed, good durability, low cost and the like, the high-ductility fiber reinforced cement-based composite material ECC has high toughness and good interface bonding performance, the hardening time of the ECC can be adjusted as required, and the high-ductility fiber reinforced cement-based composite material ECC has the advantages of high strength increase speed, high construction speed, good durability, low cost and the like. The method can comprehensively meet the requirement of comprehensive treatment of metro segments, and can be widely applied to transverse deformation structure treatment of shield metro tunnels in the operation period.

Description

Technical Field

[0001] The present invention relates to the technical field of underground engineering structure reinforcement, and in particular to a reinforcement technology for deformation of lining segments of a subway shield tunnel during operation. Background Art

[0002] During operation, shield tunnel lining segments in subway tunnels are susceptible to damage such as water seepage, cracks, localized damage, and deformation due to factors such as ground overloading, construction activities in nearby areas, and variations in soil distribution in the tunnel's strata. This is particularly true for subways built on soft soil, where disturbed soft soil takes a long time to stabilize. This can cause segmental deformation to progress, transforming the well-stressed circular shape of the tunnel into an elliptical one (commonly known as a duck egg), seriously compromising structural safety. Therefore, timely treatment of shield tunnels during operation is crucial to ensuring operational safety, and the key to addressing lateral deformation is rapid, effective, and cost-effective.

[0003] Current subway tunnel segment reinforcement technologies have the following drawbacks: 1. Steel plate lining reinforcement suffers from insufficient interfacial adhesion, low construction efficiency, and high costs; 2. Concrete arch reinforcement suffers from long construction periods and large headroom encroachments; 3. Composite cavity reinforcement suffers from complex force transmission paths and difficult joint construction. None of these existing reinforcement technologies can meet the requirements of "more, faster, better, and more economical."

[0004] The essence of lateral deformation management is to increase the stiffness of the lining segments, including bending (tensile) and compressive stiffness, by adding high-performance materials to resist deformation under uneven loads. Due to limited boundary conditions and normal operational requirements, lateral deformation management of shield subway lining segments during operation should be a "laminated" approach. Specifically, the interface between the new and old materials must be able to resist tangential shear stress and normal pullout forces.

[0005] Therefore, this paper proposes a subway segment reinforcement technology based on a combination of steel sections and high-ductility fiber-reinforced cementitious composites (ECC). This technology comprises a spatial skeleton structure composed of steel sections, a layer of high-ductility fiber-reinforced cementitious composite material poured within the skeleton, and a chemical anchor system connecting the segments to the skeleton. This technology offers the advantages of rapid strength buildup, fast construction, excellent durability, and low cost. Furthermore, ECC offers high toughness, excellent interfacial bonding, and adjustable curing time. Therefore, it is a new technology that fully meets the requirements of "more, faster, better, and more economical" and can be widely used to manage lateral deformation structures in shield-bored subway tunnels during operation. Summary of the Invention

[0006] The purpose of the present invention is to provide a subway segment reinforcement system based on a combination of steel sections and high-ductility fiber-reinforced cement-based composite materials, which is used to control the lateral deformation of subway shield tunnel lining segments during operation.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A subway segment reinforcement system based on a combination of steel sections and high-ductility fiber-reinforced cement-based composite materials consists of a spatial skeleton structure composed of steel sections, a high-ductility fiber-reinforced cement-based composite material layer poured into the skeleton, and a chemical anchor system connecting the segment and the skeleton.

[0009] Furthermore, when the system of the present invention is actually used, it is necessary to select steel sections of different sizes according to the degree of deformation of the existing pipe segments, and match the chemical anchor bolts according to the specifications of the steel sections.

[0010] Furthermore, in the present invention, the chemical anchor matches the specifications of the steel section, and the implantation depth satisfies 10d≤h≤(t-150) mm, wherein d is the anchor diameter, h is the anchor implantation depth, and t is the segment thickness.

[0011] Furthermore, the fiber content in the poured high-ductility fiber-reinforced cement-based composite material is 0.5% to 1.5% by weight.

[0012] The beneficial effects of the present invention are:

[0013] The present invention provides a subway segment reinforcement technology based on a combination of steel sections and high-ductility fiber-reinforced cementitious composites (ECC). Compared with existing methods, this technology has the advantages of a short time to reach the required strength, fast construction speed, good durability, and low cost.

[0014] The ECC selected in the present invention has the characteristics of high toughness and good interface bonding performance, and the hardening time of ECC can be adjusted according to needs, so it can fully meet the requirements of "more, faster, better and cheaper" and can be widely used in the lateral deformation structure treatment of shield subway tunnels during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the composition of the present invention.

[0016] Figure 2 Schematic diagram of tunnel deformation (elliptical deformation form) applied in the present invention.

[0017] Figure 3 This is the stress distribution diagram of the superimposed reinforcement interface of the present invention.

[0018] Figure 4 It is a schematic diagram of the three-dimensional structure of the reinforcement system in Example 1 of the present invention.

[0019] Figure 5 This is the expanded layout diagram of the segment reinforcement in Example 1 of the present invention. DETAILED DESCRIPTION

[0020] To make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is described and illustrated below in conjunction with the accompanying drawings and examples. The drawings are for illustrative purposes only and should not be construed as limiting this patent. Based on the embodiments provided in this application, all other embodiments obtained by persons of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] The present invention provides a subway segment reinforcement system based on a combination of section steel and high-ductility fiber-reinforced cement-based composite material (ECC). Figure 1 As shown, the spatial skeleton structure is composed of a steel section, a high-ductility fiber-reinforced cement-based composite material layer poured into the skeleton, and a chemical anchor system connecting the pipe segments and the skeleton.

[0022] like Figure 2 As shown in Figure 2, in actual applications, subway tunnels will have different shapes and degrees of deformation, such as Figure 2 For the elliptical deformation shown in Figure 1, different steel sizes are selected based on the existing segment deformation. Chemical anchor bolts are matched to the steel specifications and the implantation depth is standardized. Ductility is adjusted based on the fiber content of the injected high-ductility fiber-reinforced cementitious composite material.

[0023] Example 1

[0024] like Figure 4 、 5 As shown, this technology was used to reinforce a subway segment with an inner diameter of 5.5m, a ring width of 1.2m, and a thickness of 350mm. It was assumed that the segments were reinforced every other ring, with three reinforcement strips per ring. Cold-bent, externally rolled channel steel was selected based on the existing segment deformation, such as CW150×40×20×5.0 and CW200×50×30×5.0. Chemical anchor bolts, such as M18 and M20, were selected to match the cold-bent externally rolled channel steel specifications. The implantation depth was not less than 10d and not greater than 200mm. The fiber content of the injected high-ductility fiber-reinforced cementitious composite material was 0.5% to 1.5% by volume.

Claims

1. A subway segment reinforcement system based on a combination of steel and high-ductility fiber-reinforced cement-based composite materials, characterized in that The system is composed of a spatial skeleton structure made of steel sections, a high-ductility fiber-reinforced cement-based composite material layer poured into the skeleton, and a chemical anchor system connecting the pipe segments and the skeleton.

2. The subway segment reinforcement system based on a combination of section steel and high-ductility fiber-reinforced cement-based composite material according to claim 1, characterized in that: The system is configured to select steel sections of different specifications according to the degree of deformation of existing segments.

3. The subway segment reinforcement system based on a combination of section steel and high-ductility fiber-reinforced cement-based composite material according to claim 1, characterized in that: The chemical anchor matches the steel specifications, and the implantation depth satisfies 10d≤h≤(t-150) mm, where d is the anchor diameter, h is the anchor implantation depth, and t is the segment thickness.

4. The subway segment reinforcement system based on a combination of section steel and high-ductility fiber-reinforced cementitious composite material according to claim 1, characterized in that: The fiber content of the poured high-ductility fiber reinforced cement-based composite material is 0.5% to 1.5% by weight.

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