泥水平衡盾构穿越富水砂砾层施工技术研究

文章依托沈阳地铁十号线11标长青桥站—浑南大道工程,该工程区间全长1.6 km,采用?6240 mm泥水平衡盾构施工,穿越段以富水砂砾层为主,最大粒径110 mm,在施工过程中,通过优化调整刀盘的合理选型和泥浆参数,有效地减少了刀盘的磨损,全程未更换刀具。研究表明:通过分析盾构设计阶段刀盘的选型配置和隧道贯通后刀具的磨损情况,提出了一套有针对性的泥水盾构刀盘配置;通过分析施工掘进参数可知,提高泥浆粘度虽然可以增加泥浆支护效果,但易在盾构刀盘的正面形成泥饼,导致正面砾石无法顺利进入土舱内,进而造成扭矩及推力的异常;通过分析不同粘度、比重下盾构机扭矩及推力的变化,总结了富水砂砾层中泥浆参数的合理指标,对今后类似工程的施工具有借鉴意义。

Study on the Construction Techniques for Slurry Balance Shield Passing through Water-rich Sandy Gravel Stratum

A slurry balance shield with diameter of ?6240 mm is adopted for the 1.6 km long Changqingqiao sta tion-Hunnan Avenue station running tunnel of lot 11 of Shenyang metro line 10 which passes through the stratum mainly composed of water-rich gravel layer with the maximum particle size of 110 mm.The cutter wear is effectively reduced and no replacement of cutterhead is taken in the whole construction process by optimizing and adjusting the type selection of shield cutterhead and slurry parameters.The main conclusions are as follows:a set of targeted slurry shield cutterhead configuration option is put forward through analyzing the type selection and configuration of cutter head in shield design and the cutter tool wear condition after breakthrough of the tunnel;based on an analysis of driving parameters,it is found that increasing the viscosity can improve the effect of slurry support but it is easy to form filter cake on the front of shield cutterhead,thus the gravel muck at front can′t enter into earth chamber smoothly,causing occurrence of abnormal torque and thrust;the reasonable indexes of slurry parameters for slurry shield in water-rich gravel layer are summarized by analyzing the changes of torque and thrust of the shield under different viscosities and specific gravities.