浅埋富水砂层隧道复合注浆治理技术研究

青岛地铁四号线张村站横通道为浅埋富水砂层,为了解决开挖过程中面临的涌水涌砂问题,采用多方法复合注浆加固技术进行治理。模袋桩布置于重点加固区外轮廓,模袋桩工法能起到桩体加固作用,同时可以控制注浆扩散,抑制地表抬升;分段钢管桩布置于重点加固区域内部,采用分段注入的方式,均匀扩散有利于加固效果,且能避免局部不均匀注浆造成的抬升问题;在中粗砂地层中,水泥浆液的渗滤效应是不可忽视的,注浆扩散半径按1.2m进行考虑,实践证明是合理的。浅埋富水砂层注浆结束后,配合真空降水,实现了隧道内的无水施工环境。钢管桩、模袋桩和注浆三种方法构成了复合加固技术,配合其他辅助工艺方法,有效解决了浅埋富水砂层的治理难题,对类似工程具有借鉴意义。

The cross passage of Zhangcun Station of Qingdao Metro Line 4 is located in shallow water-rich sand layer.In order to solve the problem of water and sand gushing in the excavation process,a multi-method composite grouting reinforcement technology is adopted.The mold bag pile is arranged on the outer contour of the key reinforcement area.The mold bag pile method can play a role in pile reinforcement,at the same time,it can control grouting diffusion and inhibit surface uplift.The segmented steel pipe piles are arranged in the key reinforcement area,and the segmented injection method is adopted.The uniform diffusion is beneficial to the reinforcement effect and can avoid the lifting problem caused by local uneven grouting.In the mediumcoarse sand stratum,the infiltration effect of cement grout can not be ignored.The grouting diffusion radius is considered as 1.2m,which is proved to be reasonable in practice.After the grouting of shallow buried waterrich sand layer,combined with vacuum dewatering,the water-free construction environment in the tunnel is realized.The three methods of steel pipe pile,mold bag pile and grouting constitute a composite reinforcement technology.Combined with other auxiliary process methods,it effectively solves the problem of shallow buried water-rich sand layer treatment,which has reference significance for similar projects.