西二线九江盾构设备进洞技术研究

Researches on Techniques for Shield Machines Entering Holes in Jiangxi Jiujiang Section of West-East Gas Pipeline Ⅱ

由于砂层、淤泥层等软土地层承载力差,为了预防盾构设备在该类地层进洞出现涌水、涌砂,因此有必要采取措施保证盾构机成功进洞。西二线九江长江盾构项目盾构设备进洞过程中,采用降水法排除地下水,稳定开挖面土体,防止施工中产生流砂。将预埋钢板的管片以焊接的方式进行连接,加强管片之间的固定,提高隧道的整体稳定性,防止管片出现变形、环缝漏水、漏砂等现象。自行设计并委托加工了一套由两道帘布橡胶板、一环扇形压板和一道紧急密封气囊等组成的混合式密封装置,防止出现涌水、涌砂。在盾构掘进控制方面,将进洞段分为三个阶段,各对应阶段采取了相应的掘进模式。通过以上措施,实现了盾构机成功进洞。因此,盾构机在砂层等软土地层采取相关技术措施是非常必要的。

Because there is poor bearing capacity in such soft soil layer as sand layer and sludge layer,it is necessary to take some measures to ensure that shield machines enters holes successfully in order to prevent water and sands from gushing when these machines enters holes in such soft soil layer.In Jiangxi Jiujiang Section of West-East Gas Pipeline II project,dewatering method was adopted to drain out groundwater and stabilize the soil body of the excavation face so as to prevent quicksand from occurring during construction.Pre-buried steel plates were welded together with each other to strengthen stabilization between these steel plates and strengthen stability of whole tunnels so as to prevent deformation of steel plates and circumferential weld leakage.Furthermore,adopted were a kind of composite sealing devices which consist of flaps rubber sheets and a ring of fan-shaped linking pieces and emergency seal air bags.In the aspect of shield construction progress control,corresponding tunneling modes were adopted in different tunneling stages.The above technical measures were so necessary for ensuring that shield machines enters holes successfully.