Research on Deformation Behaviour of Soft Surrounding Rock Tunnel During Construction

Based on the numerical simulation method combined with in-situ data of typical projects, the spatial distribution characteristics and affect distance of deformation for soft rock tunnel were analyzed. In addition, the influence law of tunnel deformation by surrounding rock characteristics, buried depth, in-situ stress level and cross section form was discussed. It shows that the tunnelling deformation consists of the prior deformation before excavation, the deformation of woring face and the later deformation after excavation. And for the soft rock tunnels, the displacements such as the prior crown settlement before excavation, the squeezing displacement of working face and the arch springing settlement afer excavation are obvious, so it is important that strengthen the pre-support of arch crown, and stable the working face and the arch springing by taking effective measures to control the large deformation effectively. The influence factors of construction deformation in tunnel are complex, and influence each other. For this reason, be in line with the principle of overall consideration, integrated treatment, and take various means to cope with the three kinds of deformation above, can the deformation be controlled effectively for large deformation problems of soft rock tunnel.