Abstract:

Large deformation of surrounding rock is a common construction geological disaster of great harm. Some studies  were done to abate or even eliminate the influence to the engineering. First, the cause of extrusion large deformation of soft rock in a typical section was revealed based on engineering geological conditions and stress test results analysis. Then, combined with field monitoring data, stress and deformation characteristics of the rock mass were studied by a finite difference program in a soft rock section construction process. The effect of supporting structure on the surrounding rock stability was analyzed. Surrounding rock deformation was effectively controlled  by considering support, and the influence scope caused by excavation decreased from two times as much as the tunnel diameter to one time. Extrusion deformation of the working face was effectively controlled. According to the analysis of a construction process simulation considering support, control measures were presented to control the soft rock large deformation in this section, and specific treatments were proposed to deal with the intrude limit caused by large deformation. Good effects were gained by these  measures, and it has reference meaning to similar engineering.

Key words: weak and fractured, large deformation, construction mechanical behavior, support measures