In light of the problems that exist regarding back water stops for the construction joints of tunnel linings, the following improvements were tested: (1) the water stop section was designed as trapezoid, which allows two wings to go deeply into the lining concrete and allows both sides of the flange to have enough space to fill the concrete; (2) the drainage holes were set at the side towards the water, with the geotextile on the top and the lower part to connect with the tunnel drainage system; (3) with the artificial crown, the back water stop to became the middle-buried one at the top; and (4) with buried pipes in the base of the lining, the two ends of the water stop were inserted into the groove and connected with a drain pipe without any middle joints.%文章针对隧道衬砌施工缝既有背贴式止水带存在的问题,对施工缝背贴式止水带防水技术尝试了以下改进:(1)将横断面设计为梯形,使两翼能稳定深入衬砌混凝土内部,保持翼缘两侧有足够大的空间充填混凝土,从而为止水带周围密实创造条件;(2)在迎水面设置了排水孔,排水孔上覆有滤水土工布,排水孔下端与隧道排水体系相通,该排水孔给背贴式止水带赋予了排水功能;(3)通过人工假顶使背贴式止水带在洞顶成为准中埋式止水带,从而解决背贴式止水带在洞顶其周围不密实的问题;(4)通过在衬砌基础埋管留槽,安装止水带时将其两端插入槽内并接通排水管,可实现止水带无中间接头、整条一次安装,避免止水带中间接头渗漏水.
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