上马相迪A水电站引水隧洞开挖施工技术

Excavation construction technology of headrace tunnel for Upper Marsyangdi A Hydropower Station

尼泊尔上马相迪A水电站为引水式隧洞,开挖断面为中小型,隧洞长度5000 m。受地形地质条件影响,单工作面开挖距离较长,且围岩中不同程度揭露有砂卵石、云母片岩段、破碎断层带、遇水泥化层等现象。本工程克服“近90条断层、渗水量大”等不利条件顺利开挖贯通,过程中所采取的开挖技术可供类似工程参考。

The Upper Marsyangdi A Hydropower Station in Nepal adopts headrace tunnel with a small and medium-sized excavation section and a tunnel length of 5000 m.Due to the topographic and geological conditions,the excavation distance of single working face is rather long and sand pebble,mica schist section,broken fault zone,and cementation layer exposed in the surrounding rocks.This project overcame the unfavorable conditions of"nearly 90 faults and large seepage volume"and completed the headrace tunnel excavation smoothly.The excavation techniques adopted in the process can be used as reference for similar projects.