Calculation of Characteristics of Damaged Zones Surrounding Circular Tunnels Considering the Influence of Gravity Loading

This research effort, considers the true triaxial stress state and takes into account the effect of body forces due to the weight of the Excavation Damaged Zone (EDZ) to develop a new solution describing for the induced stress field within the weak medium surrounding a circular tunnel. The solution approach is based on the generalized nonlinear unified strength criterion; by changing the effect of intermediate principal stress, new solutions based on different failure criteria, e.g. Hoek and Brown and Generalized Twin Shear Stress can be obtained. Comparison of the results obtained from suggested methodology with published results shows the differences to be insignificant. The maximum relative error for EDZ thickness value and the radial stress at EDZ-EdZ interface were found to be ۱.۳% and ۱.۵% respectively. The results also demonstrate that values of EDZ thickness and induced stresses at EDZ-EdZ interface are related to the nonlinear rock mass quality and in situ stresses.

Keywords:

Tunnel , Excavation Damaged Zone (EDZ) , Body force , generalized nonlinear unified strength criterion