城市地铁大跨准平顶直墙浅埋暗挖工法及关键技术试题.docVIP

城市地铁大跨准平顶直墙浅埋暗挖Research on Method Key Technologies of Long-span Similar Flat-roof and Upright-wall with Mining Excavation of Shallow Tunnels in Urban Metro Works Yang Weihu （1st Section of Xi’an Railway Engineering Company, China Railway Electrification Bureau Group，Baoji，721000，China） [Abstract] The long-span similar flat-roof and upright-wall is one of the urban metro station ancillary works in the late form of mining structure, with the such characteristics as shallow, long-span, changes structure and construction harsh conditions, It is widespread with the complex technical problems interactions between tunnels,surface subsidence, pipeline sabotage, reasonable stress transfer in construction. This paper as an example of successful practice of long-span similar flat-roof and upright-wall with mining excavation of shallow tunnels on the No.1 wind-road of Shiliuzhuang road subway station,By summary and discussion in it’s construction method key technologies such as subsidence checked, Interactions between tunnels cut, pipeline protection, collapsed rectification, steel grill optimization and reasonable stress transfer, and making such construction method it’s key technologies with long-span similar flat-roof and upright-wall with mining excavation of shallow tunnels in urban metro works for a certain degree of complementarity and expand [Keyword] Similar Flat-roof and Upright-wall, Mining Excavation of Shallow Tunnels, Interactions between Tunnels, Subsidence Checked, Reasonable Stress Transfer 前言 近年来，随着国民经济的蓬勃发发展，国内各大城市地铁，预计21世纪初至中叶将是我国大规模建设地铁的年代，与此相关，也会涌现出大量的岩土工程技术问题解决。m，单层段40.5m，开挖轮廓线标准断面净垮14.5m，风道平面及纵剖面如图1所示。其中风道双层段属于平顶双跨直墙结构，单层段属于单跨准平顶直墙结构（微拱，矢跨比仅为0.1），采用CRD法施工；风道单层段埋深4.5m，双层段5.3m，所处地层自上而下依次为杂填土层、粉细砂层、砂卵石层、粉质粘土层，地下水位位于开挖拱底以下5m深处，风道开挖拱部位于粉细砂层，土体自稳性差，极易坍塌。 二、施工方法及步序 石榴庄路站一号风道所处地层复杂，跨度大，顶部管线密布，且管线埋置较深使得风道单层段只能设计为矢跨比为0.1的准平顶直墙结构，双层段设计为“下压”平顶以躲避管线，风道大跨准平顶直墙结构的形式决定了其受力性能的减弱。因此，降低施工风险、遏制地面沉降、保护既有管线成为风道暗挖施