胡鲁水电站尾水隧洞大断层超前强支护施工技术

Study on Strong Advanced Support Technology Applied at the Major Fault Section in the Tailrace Tunnel of Hulu Hydropower Station

马来西亚胡鲁水电站尾水洞与其下游的肯逸尔水库相连,从尾水出口掘进347 m时遇到117 m长的大断层,其中地质条件最差处是断层核心区一段长39 m的土层段,该段地下水丰富且不能自稳而发生塌方。项目部和国际知名咨询公司的德国地质专家一起,制定了采用“泡沫混凝土、灌浆、大管棚(管棚内加钢筋束)、长面钉(face nail)、小管棚桩(micro-piles)、闭环大钢拱架”等联合超前强支护技术,保留中部核心土并分区短进尺开挖,成功穿越了长断层。介绍了具体的研究与实施过程。

Tailrace tunnel of Hulu Hydropower Station in Malaysia is connected to the Kenyir Reservoir in the lower reach.When excavate inward 347m from the tailrace outlet,a major fault of 117m are encountered,among which 39m soil layer with the worst geological condition is found at the fault core area.This section collapsed due to abundant underground water and lacking of self-stability.The contractor,together with German geologist from internationally renowned consulting company,applies advanced supporting techniques such as foamy concrete,advance grouting,large tube piles(reinforced in tube piles),face nail,micro-tube piles,closed loop large steel ribs to retain the central core soil and compartments for short-length excavation,and with those measures,the major fault is successfully passed through.This paper introduces in detail the process of the study and the on-site practice of the supporting technology.