高地应力大断面特长水工隧洞灌浆施工技术

Grouting Construction Technology of Long Hydraulic Tunnels with High Crustal Stress and Large Cross-sections

在建锦屏二级水电站4条引水隧洞群穿越锦屏山主峰山体,最大埋深2525m,最高地应力值69.94MPa,隧洞施工过程中在高地应力区将出现大的涌漏水,危及隧洞的施工安全。通过对锦屏隧洞围岩地质、断面条件、工程重点与难点等因素分析,结合隧洞开挖及支护理论,并对隧洞开挖过程中的灌浆技术进行了分析和研究,确定了锦屏高地应力条件下大断面特长水工隧洞灌浆施工中制浆系统和与围岩条件相适应的灌浆参数,分析了符合施工顺序及施工过程的施工工艺。采用这种灌浆技术,保证了长大隧洞开挖围岩稳定和地下结构的安全。

The 4 diversion tunnels of Jinping secondary hydroelectric power station pass through the Mt. Jinping prominent peak mountain massif. The maximum burying depth is 2 525 m and the maximum crustal stress is 69.94 MPa. In the tunnel construction process large water leakage will arise, which will endanger the security of the tunnel construction. Through the analysis of the surrounding rock geology, cross-section conditions, key points and difficulties of the engineering, with a combination of the theories of tunnel excavation and support, as well as the study on grouting technology in the process of tunnel excavation, the paper determines the pulping system which works under high crustal stress and extremely long hydraulic tunnel and the grouting parameter which adapts to the wall rock condition, and analyzes construction technology conforming to the construction order and the construction process. The construction practice of tunnel in the initial stage showed that this grouting technology may guarantee the stability of the surrounding rocks in the excavation of long and large tunnels as well as the security of the underground structure.