地铁车站围护结构桩间初期支护模筑混凝土施工的新方法研究

Research on the New Construction Method of Model-Building Concrete of Early Supporting Formwork Between Piles of the Enclosur Structure of Subway Station

厦门地铁3号线2标五工区车站围护结构均采用钻孔灌注桩+旋喷桩桩间止水,而钻孔灌注桩作为围护结构的城市地铁基坑开挖时,需对基坑侧围护桩进行填平处理,喷射混凝土施工方法施工步骤多,周期长,成本高,基面平整度差,且对环境污染大,本工法介绍了一种地铁车站围护结构桩间初期支护模筑混凝土施工的新方法,该方法对基面外观质量可控,线型顺直,基面平整,利于防水板敷设,且钢围檩及钢支撑安装顺直,标高及轴线位置控制较好,围檩背后无脱空现象,基坑支撑安全系数较高,弥补了传统围护桩间喷射混凝土施工时混凝土表面平整度差、线性不顺直、桩间渗漏水的缺陷。

In the fifth work area of No.2 bid section of Xiamen metro line 3,the station retaining structure adopts bored cast-in-place pile+rotary jet grouting pile to stop the water.When the urban metro foundation pit with bored cast-in-place pile as the retaining structure is excavated,the retaining pile at the side of the foundation pit needs to be filled and leveled.The shotcrete construction method has many construction steps,long period,high cost,poor flatness of the foundation surface,and great environmental pollution.This method introduces a kind of construction method.The new construction method of the initial support formwork between the retaining structure piles of the subway station is controllable for the appearance quality of the foundation surface,the straight line,the flat foundation surface,which is conducive to the laying of the waterproof board,the installation of the steel purlin and the steel support is smooth and straight,the elevation and axis position are well controlled,the back of the purlin is not hollowed out,and the safety factor of the foundation pit support is high,which makes up for the spray concrete between the traditional retaining piles during the soil construction,the concrete surface has the defects of poor flatness,linear irregularity and leakage between piles.