Failure Modes and Stability Studies of Shield Face Stability for Short Distance Under Crossing Existing Tunnel Construction

摘要

The supporting pressure value of excavation face directly determines the stable state of excavation face, and its value will directly lead to instability of excavation face if the value is too small. When the shield is underneath the existing tunnel, special attention should be paid to the support pressure setting of the shield working face. The value of the shield should take full account of the stiffness constraints of the surrounding soil around the built tunnel. ABAQUS software was used to analyse the failure mode of the soil around the existing tunnel due to the instability of the excavation surface caused by the small pressure setting of the excavation face, which is caused by the small pressure setting of the excavation face. The prism is optimized to be a prism with different opening angles, which makes it closer to the actual situation, and calculates the critical support pressure of the excavation face when the shield passes through the existing tunnel. The research results can provide a reference for the effective value of the supporting force of the excavation face during the construction of the shield tunnel passing through the existing tunnel.