Study on Stability of Tunnel Excavation Face Based on Implicit Material Point Method
The reasonable design of excavation face support force is essential to ensure shield tunnel stability.Currently,numerical simulation has become a widely applied,efficient,and practical technique in tunnel engineering design.Using a self-developed material point method program,calculations are conducted on a tunnel excavation face model,with support force applied to the excavation face via the stress control method.The excavation face stability is evaluated based on the model's kinetic energy and excavation face displacement,establishing a calculation method for tunnel excavation face stability.Initially,the method's feasibility is verified through comparisons with existing experimental and theoretical models.Subsequently,parameter analyses are conducted using the control variable method to explore how internal friction angle,cohesion,and tunnel depth affect the ultimate support force and failure patterns of the excavation face.Results indicate that,within soil strength parameters,friction angle has a more significant effect on the instability region than cohesion,with both showing a negative correlation with the model's ultimate support force.Additionally,the instability region of tunnel failure decreases as tunnel depth increases.
implicit material point methodtunnel engineeringexcavation face stabilitynumerical simulationlimit support forceinstability
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