Numerical Modeling of Nonlinear Deformation Behavior of Shallow Tunnel by Strain-Softening Analysis
Shinichi AKUTAGAWA, Jae-Ho LEE and Tsutomu KITANI
Abstract:In NATM tunnel constructions passing through unconsolidated soil and shallow depths, it is inevitable that ground displacement will occur around tunnels, which may significantly affect nearby structures. Experimental and numerical analysis approaches have been undertaken to understand deformation behaviors during tunneling. This paper consists of two phases. In the first phase, a numerical model that can account for reduction of shear stiffness and frictional strength parameters simultaneously was proposed to investigate the effects of key parameters on the deformation mechanisms on key parameters, e.g. nonlinear parameters, horizontal stress ratio, and shotcrete thickness. The second phase was performed to compare model test results with those of numerical modeling, for validating the proposed strain-softening analysis method. Key Words:NATM tunnel, Strain softening analysis, Tunnel key parameters, Tunnel experimental test