Abstract:

In order to analyze the stability of surrounding rocks of Zhoushan subsea tunnel with drill-and-blast construction method, a typical cross section is chosen according to geological information. A model for numerical analysis is established according to geometrical parameters and geological information.of the typical cross section. An international calculating mode is used to simulate explosive load, and the explosive load is imposed on simulative blast holes in equivalent stress form due to characteristics of dynamic calculation of FLAC3D. By means of analysis of velocities and accelerations of survey points, it is easy to draw the conclusion that each velocity-time curve and each acceleration-time curve satisfy the explosive distortion rule; and the peak values of vibration velocities are less than failure criterion of rock. The influence scope under explosive load is within the recommendatory thickness of rock overburden. Then the rationality of recommendatory thickness of rock overburden and explosive scheme is validated. Eventually, in order to define the effects that are imposed on the surrounding rocks by the thickness of rock overburden and charge amount, the calculation results under different conditions are presented. Some conclusions are drawn so as to benefit the future construction and other analogical rock engineerings.

Key words: subsea tunnel, numerical analysis, overburden rock thickness, drill-and-blast method, explosive load, stability