Composite Tunnel Support Using Fabric Bags and Steel Frames
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Solution Overview
Problem
Existing support methods for tunnels excavated under complex geological conditions, such as deep soft rocks and faults, face challenges with stability due to low bearing capacity and susceptibility to cracking, especially with methods like bolting-steel mesh-shotcreting support and concrete arch support.
Innovation Solution
A composite supporting structure combining fabric-form bag-behind-wall grouting and high-strength support frames, where circumferential and longitudinal fabric-form bags are arranged around concrete-filled steel tube support frames, connected by high-strength fiber bundles and rods, to form a full-section composite high-strength supporting structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If bolting-steel mesh-shotcreting support is used, then the support can be installed quickly, but the bearing capacity is low and the sprayed concrete is prone to cracking
Solution Approach 1:
The patent combines multiple support materials (shotcrete, steel mesh, anchor rods, and optional steel arches) into a composite support system. The shotcrete provides immediate surface protection, steel mesh reinforces the concrete, and anchor rods provide deep rock anchoring, creating a multi-component support structure with enhanced overall bearing capacity while maintaining relatively fast installation speed.
Solution Approach 2:
The patent merges multiple support technologies (bolting, steel mesh installation, shotcreting) into a unified support system. By combining these different support methods working together, the system achieves both the installation speed advantage of mechanized methods and the bearing capacity of multiple reinforcement layers.
2Strength
If concrete arch support is used, then the bearing capacity is high, but the construction speed is slow and cracks occur during aging
Solution Approach 1:
The patent applies preliminary reinforcement measures by installing steel mesh and anchor rods before pouring the concrete arch. This preliminary action ensures that the concrete structure has inherent reinforcement from the start, preventing cracking during aging while maintaining high bearing capacity. The steel mesh is pre-positioned to provide immediate structural integrity.
Solution Approach 2:
The concrete arch is made composite by embedding steel mesh and anchor rods within the concrete structure. This composite construction provides both the high bearing capacity of concrete and the crack-resistant properties of steel reinforcement, while the pre-installed components help maintain construction speed.
3Ease of manufacture
If simple bolting-steel mesh-shotcreting support is used, then the installation is simple, but the support stability is insufficient under complex geological conditions
Solution Approach 1:
The support system uses composite materials including shotcrete, steel mesh, and anchor rods working together. The shotcrete provides surface bonding, steel mesh provides tensile reinforcement, and anchor rods provide deep rock anchoring, creating a multi-material system that maintains stability under complex geological conditions while retaining relative installation simplicity.
Solution Approach 2:
The patent merges multiple support functions into a single integrated system. The combination of bolting, mesh reinforcement, and shotcreting creates a unified support structure that addresses various failure modes simultaneously, improving reliability without significantly complicating the installation process.
Data Source
AI summary
The present invention provides a composite supporting structure combining fabric-form bag-behind-wall grouting and high-strength support frames and a construction method thereof, relating to the field of underground engineering support. The composite supporting structure comprises multiple sections of composite supporting units sequentially arranged in a longitudinal direction, wherein each of the composite supporting units comprises support frame, circumferential fabric-form bags are arranged outside top plate sections and side sections of the support frames, and longitudinal fabric-form bags and longitudinal supports are arranged in an alternating manner outside bottom plate sections of the support frames. The present invention forms an active-passive combined full-section composite high-strength supporting structure that may solve the problems of support difficulties such as high ground pressure, strong disturbance and the like of deep wells.