Numerical Study of Zonal Disintegration within a Rock Mass around a Deep Excavated Tunnel

Abstract

Zonal disintegration around a deep excavated tunnel is a characteristic of the rock mass intense fracturing phenomenon. In this paper, three-dimensional numerical tests on the failure processes of rock samples containing vertical wall semiarched tunnels are performed with the three-dimensional Realistic Failure Process Analysis (RFPA3D)–Parallel system model running on a Lenovo 1800 cluster, in order to study the configuration of zonal disintegration within the rock mass around the deep excavated tunnels. This study focuses on the zonal disintegration phenomenon in the tunnel longitudinal direction and the time-lag effect. Numerical results show that the microcracking in the disintegration zone within the model decreases gradually from the tunnel surface to the interior of the model along the tunnel longitudinal direction; the disintegration zone within the model also reduces, but the diameter of the disintegration zone becomes larger. Numerical results also indicate that an apparent time lag exists in the forming of the zonal disintegration. In other words, the zonal disintegration does not occur instantly after the excavation. Therefore, this time lag has to be considered carefully in the support design of the deep excavated tunnels.