N-J水电站地下厂房开挖支护施工技术

Construction technology of excavation and support of underground powerhouse of N-J Hydropower Station

巴基斯坦N-J水电站地下厂房区域围岩差,地质条件复杂,而厂房开挖跨度大、高度高、贯入四周高边墙的洞室多,致使厂房在开挖过程中产生了较大的围岩收敛变形,最大变形值达302 mm。以地下厂房超前地质勘探和变形监测成果为依据,从开挖施工程序、方法以及永久支护设计调整和优化等角度,详细介绍和总结了大变形条件下的地下厂房开挖施工技术及其技术要点。可供类似工程借鉴参考。

The underground powerhouse of N-J Hydropower Station in Pakistan is located in a region where the surrounding rock is poor and the geological condition is complicated. Furthermore, the powerhouse excavation is large in span and height, and many caverns pass through surrounding high side wall, causing large convergence deformation in the excavation process with the maximum value of 302 mm. Based on previous geological survey and monitoring results of deformation, the construction technolo-gy of underground powerhouse excavation under large deformation and the key technical point were introduced and summarized from the aspects of procedure and method of excavation construction, adjustment and optimization of permanent support design.