Abstract: The ground fracturing of slope in front of the tunnel face, whose horizontal distance exceeds 5 times of the tunnel section size from the tunnel face, has become an urgent issue. To address this issue, the ground fracturing of slope in front of heading face of Yangda tunnel in Guangxi caused by the tunnel excavation was studied by means of geological exploration and slope monitoring as a project example, and the following simulation model of the finite difference software FLAC^3D based on ubiquitous-joint model was suggested to simulate the ground fracturing. The response of the slope caused by tunnel excavation considering the influence of dominant joints was calculated with the finite difference software FLAC^3D based on ubiquitous-joint model and the inverse technique, and the distribution characteristics of plastic zone was laid special stress on. The results from geological exploration showed that the dip direction of the dominant joint J1 was almost the same as the slip direction of main sliding body. The results from slope monitoring showed that the maximum buried depth of main sliding body was from 15 m to 18 m and the slope sliding area after slope reinforcement was given. The results from numerical simulation showed that the maximum buried depth of main sliding body was close to that from slope monitoring results, the 63 m linear length between the two ends of the top fracture of the slope was close to that of the actual fracture, and the distance from one of the ends of the top fracture to one of the heading faces, 99 m, was close to the actual distance 90 m. The results indicate that the suggested simulation model is feasible and available and it can be referred for similar engineering.

Key words: tunnel excavation, slope, ground fracturing, geological exploration, slope monitoring, ubiquitous-joint model