盖挖逆作地铁车站施工关键工艺改进探析

Analysis of Key Technological Improvement in Construction of Metro Station by Cut-and-Cover Top-Down Method

为解决盖挖逆作车站施工中地下连续墙的预埋接驳器偏位破损、结构板采用地模施工时混凝土表观质量差、侧墙采用满堂架或斜撑架施工时混凝土浇筑质量难保证、水平施工缝处理不到位混凝土浇筑不密实、侧墙拆模过早保温保湿养护不到位极易渗漏水等问题,在深圳地铁9号线向西村站施工中对盖挖逆作关键工艺改进探析,总结出如下结论 :1)采用角钢及封盖板对地下连续墙预埋接驳器进行精确定位及保护,有效提高了接驳器的使用率;2)结构板采用矮支模体系,混凝土表观质量好;3)侧墙采用可移动式单侧支模体系,施工便捷、混凝土浇筑质量有保证;4)改进侧墙与顶板接缝处理方式,提高了接缝防水质量;5)侧墙采用双层模板带模养护,有效保证了侧墙混凝土养护条件及防水质量。

In order to solve the problems in the construction with cut-and-cover top-down method,i. e. deviation and breakage of the embedded connector for underground diaphragm wall; poor appearance quality of concrete when the construction board adopts ground formwork; uncontrollable quality of concrete when the sidewall adopts full formwork support or inclined bracing frame; uncompacted concrete pouring when waterproof treatment of horizontal construction joint is not enough and easy water leakage of sidewall induced by premature formwork dismantling not enough thermal insulation and moisture holding up. The key technological improvements in the construction of Xiangxicun Station on Shenzhen Metro Line 9 are discussed. Some conclusions are drawn as follows：（ 1） The usage of connector has been effectively improved by using angle steel and cover plate to accurately locate and protect the embedded connector for underground diaphragm wall.（ 2） The concrete has a good appearance quality when the structural template adopts short bracket system.（ 3） The construction is convenient and the concrete pouring quality can be guaranteed when the sidewall adopts movable unilateral formwork system.（ 4） The waterproof effect of joints can be improved by improving treating method for joints between sidewall and roof.（ 5） The concrete curing condition and waterproof quality of sidewall can be effectively guaranteed by adopting double-deck formwork curing system.