石家庄地铁1号线市招待所段至北国商城段为左右两线，区间隧道上方靠近一既有污水管道，污水管已使用60 a。整条区段上污水管道与隧道呈一定夹角，角度较小。其中靠近地铁车站k10＋928．290～k10＋943．59区间隧道断面尺寸有所扩大，且污水管底板距离左线隧道拱顶仅6．8 m，该区段既有污水管在隧道开挖过程中可能存在安全风险，并且受污水管可能的渗水影响，隧道本身开挖过程中也存在稳定问题。分别分析了隧道开挖过程中既有污水管底板、边墙和拱部横向和纵向应力分布规律，并通过分析纵向不均匀沉降和纵向应力分布的关系，对隧道开挖过程中既有污水管的破坏机制进行了探讨。最后针对工程特点，提出了改进的超前加固方案。石家庄地铁为石家庄市新建工程，对工程后续建设具有一定的借鉴意义。%Metro Line 1 from City Hostel to North Mall in Shijiazhuang has two lanes , the top of which is close to a sewage pipe that has been used for 60 years.There is a small angle between the sewage pipe and the tunnel.The section size of tunnel segment k 10+928.290~k10+943.59 near a metro station is larger and there is only about 6.8 meters from the base plate of the sewage pipe to the top of the left tunnel .The sewage pipe in this section maybe face risk during tunnel excavation and tunnel excavation will also face stability risk because of possible seepage .This paper mainly analyzes the horizontal and vertical stress distribution of base plate , side wall and arch of the sewage .Through the analysis of the longitudinal uneven settlement and vertical stress distri-bution, this paper discusses the failure mechanism of the existing sewage during tunnel excavation .On this ba-sis, this paper introduces improved forepoling proposals in view of the engineering characteristics , which may be of reference value for other tunnel construction in the city .
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