Influence of portal excavation of shallow-buried bias tunnel on stability of soil‒rock bedding slope: a case study of Moziping tunnel
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View abstract on PubMed
Summary
This summary is machine-generated.Tunnel excavation in mountainous areas can destabilize soil-rock slopes. This study reveals deformation patterns and failure modes, providing a method to evaluate slope stability for safer tunnel construction.
Area Of Science
- Geotechnical Engineering
- Tunneling Engineering
- Slope Stability Analysis
Background
- Excavating tunnel portals in shallowly buried bias tunnels in mountainous regions poses significant risks of soil-rock bedding slope instability.
- This instability threatens the safety of tunnel construction projects.
Purpose Of The Study
- To investigate the impact mechanism of tunnel excavation on the stability of soil-rock bedding slopes.
- To develop a reliable method for evaluating slope stability in composite strata.
- To reveal slope deformation patterns and failure modes during tunnel portal excavation.
Main Methods
- Theoretical analysis using the transfer coefficient method to establish a mechanical model of a tunnel-soil-rock bedding slope.
- Numerical simulation to assess slope stability.
- Field monitoring to observe deformation and failure characteristics.
- Development of a slope stability evaluation method for composite strata.
Main Results
- Theoretical and numerical simulations showed high agreement (4% difference) in stability coefficients (1.18 and 1.13, respectively), validating the proposed theoretical method.
- Slope deformation progresses through three stages: rapid (≤0.22D), slow with rebound (0.22D-2.63D), and stable (>2.63D).
- Interlayer sliding at the soil-rock interface causes significant horizontal displacement and promotes slip surface formation, with plastic strain concentration at the slope toe triggering instability.
Conclusions
- The proposed theoretical method reliably evaluates the stability of soil-rock layered slopes after tunnel excavation.
- Understanding the three-stage deformation pattern and the role of interlayer sliding is crucial for predicting slope behavior.
- The findings provide a theoretical basis for ensuring the safety of tunnel construction in mountainous areas with soil-rock layered slopes.
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