考虑地层渗透性的盾构隧道施工期管片上浮预测  

Prediction for shield tunnel segment uplift considering the effect of stratum permeability

作　　者：舒瑶[1] 季昌[1] 周顺华[1] 何超[1] 黄钟晖 张世荣 

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]南宁轨道交通集团有限责任公司,广西南宁530029

出　　处：《岩石力学与工程学报》2017年第A01期3516-3524,共9页Chinese Journal of Rock Mechanics and Engineering

摘　　要：地层渗透性影响盾尾同步注浆浆液的凝固,从而影响施工期管片上浮。针对目前施工期管片上浮分析缺乏考虑地层渗透性影响的不足,将同步注浆浆液视为牛顿流体、土层简化为多孔介质,利用渗透力学及流体力学原理,提出渗滤效应下同步注浆浆液固结时间的计算方法;进而将不同地层浆液固结时间、浆液性质及施工掘进速度等因素,表征为管片上浮分析的等效梁模型中的浆液未凝固区长度,对等效梁模型进行改进,建立考虑不同渗透性地层中同步注浆浆液固结特性的管片上浮分析模型,并编制有限元程序对其求解。利用此模型对南宁某含粉砂–圆砾、砂层及粉质黏土等地层的盾构区间施工期管片上浮特性进行分析,结果表明:考虑地层渗透性影响的等效梁模型进一步揭示了地层特性影响管片上浮的作用机制,其计算结果与现场实测数据具有更好的一致性,更适合于不同渗透性地层管片上浮分析。同时得到,地层渗透性越小,同步注浆浆液固结时间越长,盾尾浆液压力消散越慢,管片上浮量值越大。Stratum permeability affects the consolidation of shield tunnel simultaneous grouting, thus affecting the segments uplift during construction period. Since the analysis of shield tunnel segment uplift during tunnel construction does not consider the impact of strata permeability, assuming the grout of simultaneous grouting as Newtonian fluid and the soil as porous media and applying the theory of penetration mechanics and fluid mechanics, a calculation method for the consolidation time of simultaneous grout under the condition of filtration effect in permeable stratum was proposed. Then the equivalent continuous beam model for shield tunnel segment uplift analysis during tunnel construction was revised by putting the consolidation time and the properties of simultaneous grout, excavating velocity into the length of unconsolidated zone in the equivalent continuous beam model. Thus an equivalent beam model for shield tunnel segment uplift calculation considering the consolidation properties of simultaneous grout under the condition of filtration effect in permeable stratum was established and FEM programing was employed to solve this model. The rule of shield tunnel segment uplift during tunnel construction in stratum of silty sand and cobble, sand and silty clay in Nanning was investigated based on this model. And the result shows as follows： The equivalent beam model considering the effect of stratum permeability further reveals the mechanism for the formation characteristics influencing segments uplift. Besides, the calculation results match well with the measured data in situ and the model is more suitable for segment uplift analysis in different permeability stratum. Meanwhile, we draw the conclusion that the weaker the stratum permeability, the longer consolidation time for simultaneous grout, the longer dissipation time for simultaneous grout pressure and the greater the magnitude of tunnel segment uplift.

关 键 词：隧道工程 盾构隧道 管片上浮 等效梁 渗滤效应 

分 类 号：U45[建筑科学—桥梁与隧道工程]