Finite Element Analysis of Damage in Tunnel Floor Through Strength Reduction

摘要

Transformation method of different yield criterions was put forward and relation expressions of the shear safety factors of tranditional Drucker-Prager and modified D-P model were obtained under plain strain condition. Based on finite element strength reduction method, tunnel floor was brought into failure state through changing field variables to reduct strength parameters. By numerical simulaton, variation trend of the element node displacement, equivalent plastic strain, stress with the reduction coefficient were analyzed and the potential rupture surface of tunnel floor was obtained through connecting the equivalent plastic strain mutation points. Taking the sudden increasing of displacement at critical point as evaluation criteria, the stability safety coefficient was calculated which provide theoretical basis to select suitable reinforcement parameters.