In order to study the damage distribution of tunnel’s surrounding rock

firstly

an elastoplastic damage constitutive model of Q2 loess is deduced based on triaxial shear tests and compiled as a user-defined damage model( UDM ) of FLAC3D. Then the conception of surrounding rock damage degree (SRDD) is put forward and compiled into a post-processing module. Based on the first loess multi-arch tunnel of road–Lishi tunnel

the damage position of tunnel’s surrounding rock of two construction schemes is numerically simulated. The research results show that the SRDD and damage localization rules can be simulated well at every excavation step; and it also provides reference for the optimization of tunnel construction scheme. The research results provide a new method for the optimization of tunnel construction scheme and choice of construction scheme.