三峡明渠截流与三期土石围堰工程综合施工技术

Comprehensive construction technology for the open channel clos ure and the third stage of earth-rock cofferdam at Three Gorges Project

三峡明渠截流与三期土石围堰分为水下填筑、水上填筑和防渗工程.水下填筑主要为导流明渠截流和水下围堰,导流明渠截流具有水力学指标高、施工时间短、工程量大、抛投强度大等特点,实现明渠双戗堤立堵截流,解决了龙口段施工技术、上下游戗堤进占相互配合、设置拦石坎和提高抛投强度、防止堤头塌滑等问题.防渗工程由防渗墙、帷幕灌浆、混凝土墙帽与土工织物组成,是围堰工程的关键项目,在此提出了有效的施工技术和质量控制措施,确保了施工工期和施工质量.

The open channel closure and the third s tage of earth-rock cofferdam at Three Gorges Project include under-water fills,ab ove-water fills and seepage-control work. The part of under-water fills mainl y comprises the diversion channel closure and under-water cofferdam constructio n. Realizing the diversion channel closure, characterized by high hydraulic ch aracteristics, short construction period, large volume of work and strong inte nsity for material dumping, has relied on the method of full-front closure alo ngside a double banquette to overcome difficulties in the final gap closure, to ensure the interaction of the upstream banquette with the downstream one, to r aise the height of rock dumping, and to avoid collapses. The seepage-control w ork is composed of a seepage-control wall, grout curtain, concrete cap for wa ll and geofabric work. It is the centerpiece to ensure the cofferdam stability. Some measures related to construction techniques and quality control are also pr esented in this article.