长潭河水利枢纽导流隧洞进口段开挖及支护设计

Excavation and support design for diversion tunnel inlet section of Changtanhe Hydraulic Complex

长潭河水利水电枢纽工程导流隧洞进口段岩石风化,层间错动及节理裂隙发育,岩体结构松散,开挖时存在围岩稳定问题。为保证隧洞及早进洞和施工期安全,对该段采取先开挖导洞再进行扩挖并采用管棚法施工。介绍了隧洞进口段开挖与支护的设计。

There exist weathered rock mass, interlayer faults and developed joint fissures at the inlet section of the diversion runnel of Changtanhe Hydraulic Complex. Loose rock may lead to stability problem of surrounding rock during excavation. In order to accelerate tunneling while ensuring construction safety, a pilot tunnel is excavated first before expansion excavation with pipe-roof method adopted. The author also introduced the excavation and support design for the inlet section of the tunnel.