富水软弱围岩浅埋隧道防水施工技术优化研究

Study on the optimization of waterproof construction technology for shallow tunnel in water-rich soft surrounding rock

为解决富水软弱围岩浅埋隧道容易出现渗漏水的施工难题,本文结合某隧道工况,采用新工艺、新工装、新设备提高注浆和二衬的防水质量,在隧道浅埋段采用地表袖阀管注浆工艺,并借助改进的袖阀管和止浆塞对隧道初期支护轮廓线周围500~600 cm内软弱围岩进行袖阀管高压劈裂分段定位注浆,从而形成n形加固防水拱,有效阻止地层渗水,增强围岩稳定性,缩小注浆区域;二衬施工采用充填混凝土防水板铺挂新工艺,确保防水板平展性,保证衬砌密实;引进新型充填混凝土防水板铺挂台车,可以实现防水板自动铺挂和焊接;衬砌台车采取新型L形折页式端头模板,有效提高了止水带的施工质量以及封端模的工效,节约了施工成本,提高了二次衬砌防水效果,保证隧道施工和运营安全,相关施工经验为同类型隧道的防水施工提供借鉴。

In order to solve the construction problem of shallow tunnel with rich water and weak surrounding rock,which is prone to water leakage,this paper adopts new technology,new tooling and new equipment to improve the waterproof quality of grouting and secondary lining in combination with the working conditions of a tunnel:the surface sleeve valve pipe grouting technology is used in the shallow-buried section of the tunnel,and the sleeve valve pipe high-pressure fracturing sectional positioning grouting is carried out for the soft surrounding rock within 500-600 cm around the initial support contour line of the tunnel with the help of the improved sleeve valve pipe and grout stop plug,thus forming n-type reinforced waterproof arch,effectively preventing formation water seepage,enhancing the stability of surrounding rock,and reducing the grouting area;The second lining construction adopts the new technology of filling concrete waterproof board to ensure the flatness of the waterproof board and the compactness of the lining;The introduction of a new type of concrete filled waterproof board laying and hanging trolley can realize the automatic laying and welding of waterproof boards;The lining trolley adopts a new L-shaped folding end formwork,which effectively improves the construction quality of the water stop and the work efficiency of the end formwork,saves the construction cost,improves the waterproof effect of the secondary lining,and ensures the safety of tunnel construction and operation.The relevant construction experience provides a reference for the waterproof construction of the same type of tunnel.