杭州地铁汽高区间全断面圆砾层承压水条件下盾构施工关键技术

在我国经济体系越发稳定的今天,国内地铁系统的建设速度不断提高。国内各地几乎都在兴建地铁项目,众多且复杂的地质问题成为了地铁建设最大的挑战。杭州地区属于具有高压缩性、低承载力、高灵敏性及高触变性的淤泥质黏土层。但在周边区域,出现了具有承压水作用的全断面圆砾地层,隔水层为上覆的淤泥质土及下卧风化基岩层,主要特点为圆砾石粒径级配差且夹杂粘土,承压水层总厚度较大且水力联系密切。从当前全国施工经验来看属于盾构不适合施工地层,目前在杭州地区对全断面承压水圆砾地层研究成果较少。本文以杭州地铁为例,针对杭州全断面圆砾地层勘察研究成果,并借助于南宁、成都在相似地层的施工经验结合本工程特点,总结了从盾构机选型、刀具配置、掘进参数、渣土改良、沉降控制及端头加固等方面措施,以便为更多业界人士作业提供思路上的支持。

Key Techniques of Shield Construction under Confined Water Condition of Full Cross Section Gravel Layer in Hangzhou Metro

Today,as China's economic system becomes more and more stable,the construction speed of the domestic subway system continues to increase.In almost all over the country,subway projects are under construction,and numerous and complex geological problems have become the biggest challenges in subway construction.The Hangzhou area belongs to silty clay layer with high compressibility,low bearing capacity,high sensitivity and high thixotropy.However,in the surrounding area,a full-section boulder formation with confined water appears.The water-proof layer is overlying muddy soil and beneath weathered bedrock layer.The main feature is that the grain size of the conglomerate is poor and the clay is mixed and the total thickness of the confined water layer is large and the hydraulic connection is close.Judging from the current national construction experience,the shield is not suitable for construction strata.At present,there are few research results on the full-section confined water conglomerate stratum in Hangzhou.This article takes the Hangzhou Metro as an example,based on the survey and research results of Hangzhou's full-section gravel strata,and with the help of the construction experience of Nanning and Chengdu in similar strata and combined with the characteristics of this project,summarizes the measures,such as,the selection of shield machine,tool configuration,driving parameters,slag improvement,settlement control and end reinforcement,which provides thought support for more people in the industry.