Study on the Vertical Rational Structure of Tunnel Lining in the Fault-Rupture Zone

Abstract

Related to the actual project in the new Qi Daoliang tunnel between Lanzhou and Lintao highway, select 300-meter calculation range along the tunnel vertically including fault-rupture zone and effect fault-rupture zone, utilize 8 -node, 6-plane block element to scatter the calculating range, at the same time, use the deduced 8 -node, three dimensional jointed element to imitate the transformation gap of the tunnel lining, employ three-dimensional elasto-plastic static finite element program to analyze stress and transformation state of surrounding rock and lining in different construction stages of the new Qi Daoliang tunnel. Through the analysis and comparison of the calculation result of the three conditions: not placing transformation gap through, placing one transformation gap in the middle of the fault-rupture zone, placing two transformation gaps in the beginning and the end of the fault-rupture zone etc, we can get the following points: ①The gallery transformation in the fault-rupture zone and the plastic area in the surrounding rock are obviously bigger than the non-fault-rupture zone. ②Owing to the effect of fault-rupture zone, the increasing range of internal force of the initial support and twice lining is about 10% to 30%. ③Placing the transformation gap in the fault-rupture zone can obviously play a role in releasing lining internal force and transformation energy in the surrounding rock. ④In the start and end changing point of fault-rupture zone, the transformation gap should be placed in the tunnel lining.