二期上游围堰防渗墙的施工技术

三峡二期上围堰防渗墙是围堰工程成败的关键，在施工中大量采用了先进的大型设备，如ＢＣ－３０液压铣槽机，机械式抓斗，冲击式反循环钻机，高压旋喷泵等。同时大量采用了新工艺，新材料，新技术，如用“铣爆”法，“铣抓钻结合”法成槽；用“双反弧接头槽”法，“铣削”法连接；用于灌浓浆法处理漏失地层；用反循环泵吸法清孔换浆等，既满足了防渗墙高施工要求，又确保了工程质量，为我国防渗墙施工开创了新局面。

Construction Technology of Cut-off Wall in Cofferdam

The construction of the cut - off wall in the second - phase upstream cofferdam at the Three Gorges Project is the key item for the cofferdam works. A number of advanced construction equipment was employed, such as BC - 30 hydraulic trench cutter, automatlc crab, re - circular impulsive drill, hlgh - pressure rotary jet pump, etc. Meanwhile, many new techniques were applied,e. g., trenching processes and cutting, chlseling and blasting, and by cutting, crabbing and drilling; overlapping by double-counter-arc joint trench, and by cutting; pre - grouting thick mix into leaking strata; and cleaning of holes and changing of new mortar with re - circular pump. The new equipment and techniques not only met the construction requirements, and also ensured the construction quality of the cut - off wall, and initiate a new prospect for construction of cu -off wall in China.