Abstract:

Separated tunnel is a primary job practice in deep and overlength highway tunnel. Taking into account the diversity of construction progress of two tunnels, it is put forward that the study of rockburst prediction of the tunnel excavated slower through the rockburst condition of the tunnel excavated quicker. In order to investigate the rockburst influence of the tunnel excavated quicker to the tunnel excavated slower, a series of calculations and analyses are carried out by using the FEM; and some results are obtained. When horizontal stress is equivalent to vertical stress in initial stress field, the rockburst intensity of arch bottom of the tunnel excavated slower will increase with the increment of lateral pressure coefficient and the decrease of tunnel clear distance; when horizontal stress is dominant in initial stress field, the rockburst intensity of crown of the tunnel excavated slower will decrease with the increment of lateral-stress coefficient and the decrease of tunnel clear distance. Finally, the practical example demonstrates that the rockburst situations of the tunnel accord with the analytical result of the method.

Key words: separated tunnel, rockburst, lateral-stress coefficient, finite element simulation, tunnel clear distance