Abstract To explore the failure mechanism of tunnel structures in earthquakes, a static field was imposed to dynamic calculation by shifting the boundary between static and dynamic, which was taken as an initial stress condition for the improvement of the dynamic strength reduction method, the feasibility of which was proven by a computing application. The improved dynamic strength reduction method is used to calculate and analyze the failure mechanism of deep and shallow buried tunnels under seismic action, and the results show that failure processes are different for tunnels with different depths. For the shallow-buried tunnel, failure begins at the two sides above the tunnel and gradually forms a fracture plane cutting through the ground; for the deep tunnel, the plastic strain first occurs at four stress-concentrated corners with a smaller plastic strain on the crown and floor, and then a continuous plastic strain zone is formed gradually from the two sides until failure finally occurs. In light of seismic action, this paper analyzes the factors affecting tunnel failure, studies the failure mechanism of tunnel structures of different surrounding rock grades, spans, structure types, and buried depths, and finally carries on a comparative analysis for each influence factor.
Abstract：
To explore the failure mechanism of tunnel structures in earthquakes, a static field was imposed to dynamic calculation by shifting the boundary between static and dynamic, which was taken as an initial stress condition for the improvement of the dynamic strength reduction method, the feasibility of which was proven by a computing application. The improved dynamic strength reduction method is used to calculate and analyze the failure mechanism of deep and shallow buried tunnels under seismic action, and the results show that failure processes are different for tunnels with different depths. For the shallow-buried tunnel, failure begins at the two sides above the tunnel and gradually forms a fracture plane cutting through the ground; for the deep tunnel, the plastic strain first occurs at four stress-concentrated corners with a smaller plastic strain on the crown and floor, and then a continuous plastic strain zone is formed gradually from the two sides until failure finally occurs. In light of seismic action, this paper analyzes the factors affecting tunnel failure, studies the failure mechanism of tunnel structures of different surrounding rock grades, spans, structure types, and buried depths, and finally carries on a comparative analysis for each influence factor.
SUN Chang-Xin-1,
2 ,
吕Xiao-Chun-1
.Discussion of the Seismic Failure Mechanism of a Tunnel Based on the Improved Dynamic Strength Reduction Method[J] MODERN TUNNELLING TECHNOLOGY, 2014,V51(6): 41-49
2014, Vol. 51 