射水法、锯槽法造防渗墙施工质量控制

结合长江重要堤防同马大堤加固工程I、II标段垂直防渗墙施工实践,论述了射水法、锯槽法施工工艺及其特点.射水法成墙施工工艺简单,对各种地层的适应能力强,机具经改进后,可穿透卵石层、块石等障碍物,成墙最大深度可达28.5 m,但槽孔的垂直度要求高,槽孔的倾斜度控制是质量控制的重点和难点.锯槽法成墙施工工艺相对复杂,对地层也有一定要求,但成墙具有连续性,成墙质量易于保证,质量控制的重点是土工布隔离体及槽内混凝土的浇筑质量.施工完成后,通过开挖探坑、取芯等检查,防渗墙接头、墙体质量均符合要求.

Quality control for seepage prevention wall construction by water jet and trentch-cutting method

Based on the construction practice of the vertical impervious core in the No.1 and No.2 bidding sections of the important Tongma dyke strengthening works of the Yangtze River,the construction technology and characteristics of the water jet method and the trench-cutting method are expounded.The construction technology of impervious cores by water jet method is simple and well suitable for various strata.After the construction equipment for this method is improved,it can penetrate cobble strata,rock blocks,etc.,and construct impervious cores with their depth up to 28.5 m.The inclination control of trenches is the key and difficult point in quality control for the water jet method,because an accurate verticality of trenches is required.The construction technology of impervious cores by the trench-cutting method is relatively complicated and only suitable for a limited sort of strata,but the impervious core can be successively constructed and its quality is easy to guarantee.For the trench-cutting method ,the focal point of quality control is in the body isolated by geotechnical cloth sacks and the placement of concrete in trenches.The inspection of completed impervious cores through excavating exploratory pits and core extraction shows that the quality of the impervious core body and its joints meets the design requirements.