Abstract:

The surrounding rocks of Wanggangshan Tunnel are subclassified based on railway design standards and surrounding rock classification standards; the tunnel construction process is simulated by finite element software ABAQUS considering excavation direction, complex surrounding rock conditions and fault and fracture zone; and the characteristics of stress and deformation of tunnel lining and surrounding rock after threebench excavation are obtained. And then, the doubleside drift method which is favourable for deformation control is put forward; and the deformation control effect is verified. Finally, the influencing factors on deformation of tunnel lining and surrounding rock are analyzed; and the optimal advancing parameters and primary/temporary support mode are obtained. The numerical calculation results show that: 1) The excavationinduced deformation of tunnel lining and surrounding rock can be effectively controlled by doubleside drift method. 2) The anchor bolt plays a significant role in complex strata. 3) Cyclic advancing and primary support strength have influence on excavation induced deformation; and the deformation of tunnel lining and surrounding rock can be effectively controlled by using new composite segment primary support. 4) The fault and fracture zone is the key to Wanggangshan Tunnel; as a result, rational excavation method and relevant auxiliary surrounding rock disturbance reducing methods should be adopted.

Key words: Wanggangshan Tunnel, superlarge crosssection tunnel, subclassification of surrounding rock, threebench method, doubleside drift method, 3D numerical simulation