Tunnelling and Underground Space Technology· 2024Q1
Collapse mechanism and treatments of a deep tunnel in the weathered granite fault zone
- 41citations
- Q1SCImago
- 2024year
Short summary
Tunnel excavation in weathered granite fault zones can trigger collapse by activating fractures that erode and expand, reducing rock stability. Discrete element modeling revealed an 'collapse arch' and asymmetric failure due to uneven stress fields.
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Key points
- Tunnel excavation activates granite fracture zones, leading to erosion and water ingress.
- Water erosion and expansion of fissures are the primary causes of reduced rock stability.
- Discrete Element Method (DEM) simulation showed a 'collapse arch' and asymmetric failure.
- Uneven stress fields correlate with the observed asymmetric tunnel failure.
- Effective treatments included grouting, enhanced support, and pipe roofs.
AI-generated from the title and abstract; the full text is not read.
Abstract
Tunnelling in the fault fracture zone is prone to collapse accidents. The failure characteristics and mechanism of a tunnel collapse in Qinghai were analyzed based on the theory of rock mechanics, discrete element method (DEM), and in-situ test. The results show that the construction disturbance leads to the activation of the granite fracture zone, in which many fissures are constantly eroded and expanded to conduct water, which is the main reason for reducing surrounding rock stability after tunnel excavation. DEM simulates the failure process of the surrounding rock, and the collapse arch is observed. The uneven distribution of the stress field in the whole model is consistent with the tunnel’s asymmetric failure phenomenon. Based on the results, treatments such as grouting, enhanced primary support, and advanced pipe roofs were adopted to improve the mechanical properties of fissures and enhance the stability of the surrounding rock. This case provides valuable lessons for similar tunnels.
The authors' abstract, as published at the source. Tunnelling and Underground Space Technology, 2024 · DOI ↗
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Field: General Engineering
General EngineeringEngineering