THE ZONAL DISINTEGRATION MECHANISM OF SURROUNDING ROCK AROUND DEEP SPHERICAL TUNNELS UNDER HYDROSTATIC PRESSURE CONDITION： A NON-EUCLIDEAN CONTINUUM DAMAGE MODEL

A new non-Euclidean continuum damage model is proposed to investigate the zonal disintegration phenomenon of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition as well as the total elastic stress field distributions. The elastic stress fields of the surrounding rocks around deep spherical tunnels under hydrostatic pressure condition are obtained. If the elastic stresses of the surrounding rocks satisfy the strength criterion of the deep rock masses, the number, size and location of fractured and nonfractured zones are determined. The effect of physico-mechanical parameters of the surrounding rocks on the zonal disintegration phenomenon is studied and numerical computation is carried out. It is found from numerical results that the number, size and location of fractured and non-fractured zones are sensitive to the physico-mechanical parameters of the surrounding rocks.