Single-Layer Tunnel Lining with Fiber-Reinforced Concrete
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Solution Overview
Problem
The existing tunnel supporting systems based on the mine-tunnelling method face challenges such as complex construction processes, poor concrete pouring quality, and low construction efficiency, particularly in large-section tunnels, due to the need for secondary lining structures and complicated excavation methods.
Innovation Solution
A single-layer lining tunnel structure method is developed, which simplifies the construction process by removing temporary supports and using compactness agents and high-strength fibers in concrete to enhance durability and impermeability, along with a special spraying process, and grouting pipes to improve resistance to surrounding rock and water infiltration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a composite lining structure with initial support and secondary lining is used, then the tunnel can resist stratum deformation and water load, but the construction process becomes complicated and construction efficiency decreases
Solution Approach 1:
The patent extracts and removes the secondary lining structure from the traditional composite lining system, retaining only the initial support as a single-layer lining. This eliminates the complex construction processes of waterproof board installation, steel bar binding, formwork erection, and concrete pouring associated with secondary lining, while the initial support is designed to bear both construction and operational loads directly
Solution Approach 2:
The initial support structure is designed to perform multiple functions: it provides temporary support during construction, serves as the permanent tunnel lining, resists stratum deformation, and withstands water and operational loads. This multi-functional design eliminates the need for separate secondary lining structures
2Reliability
If a composite lining structure with waterproof boards and secondary lining is used, then water infiltration is prevented, but the construction process becomes more complex and time-consuming
Solution Approach 1:
The patent removes the separate waterproof board layer and secondary lining concrete structure from the traditional system. Instead, the initial support uses sprayed concrete with added waterproofing agents and compactness agents that provide inherent waterproofing properties, eliminating the need for separate waterproofing layers and secondary lining construction
Solution Approach 2:
The patent changes the chemical parameters of the sprayed concrete by adding waterproofing agents and compactness agents, transforming it from a simple support material to a composite material with enhanced waterproofing and impermeability properties, thereby achieving waterproofing function within the single-layer lining structure
3Ease of manufacture
If traditional sprayed concrete without additives is used, then the construction process is simple, but the concrete durability and impermeability are insufficient
Solution Approach 1:
The patent creates a composite concrete material by combining sprayed concrete with waterproofing agents, compactness agents, and high-strength fibers. This composite material maintains the ease of sprayed application while significantly enhancing durability, impermeability, and structural performance for long-term tunnel operation
Solution Approach 2:
The patent modifies the chemical and physical parameters of the concrete by incorporating various additives and fibers, changing it from ordinary sprayed concrete to a specialized composite material with enhanced durability, waterproofing, and structural properties suitable for single-layer lining applications
4Ease of operation
If grid steel frames with sprayed concrete are used as initial support, then stratum deformation is controlled during construction, but the overall structural rigidity is insufficient for single-layer lining
Solution Approach 1:
The patent combines grid steel frames with heavily reinforced sprayed concrete containing high-strength fibers and additives, creating a composite structure that maintains the deformation control advantages of steel frames while achieving the structural rigidity necessary for single-layer lining to withstand operational loads independently
Solution Approach 2:
The patent enhances specific local properties of the sprayed concrete by adding high-strength fibers and compactness agents in concentrated amounts, creating zones of enhanced strength and rigidity within the lining structure to compensate for the reduced overall thickness compared to secondary lining
Data Source
AI summary
Provided are a system and construction method of a single-layer lining tunnel structure based on a mine-tunnelling method. With the single-layer lining tunnel structure, a structural rigidity and durability of the tunnel are improved. A construction process of sprayed concrete is improved, specifically, compactness agent and durability enhancing fiber are added to concrete to improve the compactness of concrete, and a special spraying process is adopted to reduce a bound rate of the concrete, and thus to improve the impermeability of sprayed concrete to reach a impermeability level of waterproof concrete. Steel fiber, cellulose fiber, synthetic fiber and other materials are added into the concrete can improve the tensile strength, crack resistance and durability of the concrete.