三峡工程二期下游土石围堰防渗墙施工难点与对策

Difficulties of Construction of Anti-seepage Wall at the Lower-reach Earth Cofferdam of the Second-phase Three Gorge Project and Countermeasures

三峡工程二期下游土石围堰堰体防渗采用单排塑性混凝土防渗墙、上接土工膜、下接帷幕灌浆形式。造墙施工因墙深、面积大、地层条件复杂、工期紧等因素,给施工带来了许多难点。施工过程中为此采取了一系列的技术措施和对策,使得造墙施工得以按期、优质完成任务,并为二期工程按时开工提供了可靠的保障。

The single-row plastic concrete anti-seepage wall with its top connecting with earth mantle and its bottom with curtain grouting is adopted to protect the lower-reach earth cofferdam of the second-phase Three Gorge project from seepage. A lot of difficulties arise from the construction of wall because of great depth, large area, complicated stratigraphical conditions and short construction period of time. For this reason, a series of technical measures and countermeasures are taken during construction so as to finish the task of wall construction on schedule and with high quality and to provide guarantee for starting work of the second-phase project on time. This paper will introduce these difficulties and countermeasures arising from the construction.