导流隧洞钢拱架与喷锚支护体系有限元分析

钢拱架支撑是地下洞室开挖中的重要支护型式之一,与喷锚支护措施相结合能够有效地控制围岩变形和减小围岩失稳机率.结合某水电站工程实际,针对不支护、喷锚支护、钢拱架与喷锚联合支护等不同情况,采用三维有限元法对导流洞开挖过程中围岩的位移、塑性区,喷层、锚杆及钢拱架的应力分布情况进行了计算分析.结果表明:与普通的喷锚支护相比,采用钢拱架与喷层、锚杆组成联合支护体系能够对围岩变形提供直接抗力,围岩位移和塑性区范围大大减小,各支护材料的应力也有较大程度的降低,为导流洞围岩破碎洞段施工期的稳定提供了有力的保证.

Finite element analysis of combined support system of steel arch shelf and lock bolting with shotcrete in diversion tunnel

Steel arch shelf support is an important support style.It can be combined with shotcrete and anchoring support to effectively control surrounding rock deformation and to reduce the possibility of instability.In accordance with the diversion tunnel of a hydropower station,different schemes of no support,support with shotcrete and anchoring and steel arch shelf combined with shotcretc and anchoring support have been studied by means of finite element method.The surrounding rock displacements,plastic zone and the stresses of steel arch shelf,bolting and shotcrete are analyzed.Compared with the ordinary shotcrete and anchoring support,the surrounding rock displacements,plastic zone as well as the support stresses become much smaller because the steel arch shelf combined support can provide direct resistance to surrounding rock deformation.The combined support system can effectively guarantee the surrounding rock with fracture zone stability during the diversion tunnel construction period.