考虑盾壳与土体摩擦力的盾构下穿既有地铁隧道施工控制研究  

Construction Control of Shield Tunneling underneath Existing MetroTunnel Considering Friction between Shield Shell and Soil

作　　者：来弘鹏[1] 王腾腾 张林杰 袁野 罗维 LAI Hongpeng;WANG Tengteng;ZHANG Linjie;YUAN Ye;LUO Wei(School of Highway,Chang′an University,Xi′an 710064,Shaanxi,China;China Railway Beijing Engineering Group Co.,Ltd.,Beijing 102308,China)

机构地区：[1]长安大学公路学院,陕西西安710064 [2]中铁北京工程局集团有限公司,北京102308

出　　处：《隧道建设（中英文）》2021年第5期729-739,共11页Tunnel Construction

基　　金：国家自然科学基金项目(51978064)。

摘　　要：摩擦力是盾构下穿对既有结构施工力学行为影响的重要因素。为明确盾构下穿过程中土舱压力、注浆压力、摩擦力对既有隧道变形的影响规律,给出合理的施工技术参数,考虑盾构自重及土压力分布特征,推导了摩擦力计算公式,分析了摩擦力分布特征,将此计算结果通过Fish语言写入FLAC 3D有限差分软件,结合实体工程,对盾构下穿既有地铁隧道施工技术参数进行了系统研究,并通过实测数据验证了研究成果的可靠性。研究结果表明:1)盾壳与土体之间的摩擦力沿盾壳四周不均匀分布,量值随土体内摩擦角、重度及隧道埋深的增大而增加;2)盾构下穿过程中,既有结构竖向位移表现为先隆起、后沉降,其中土舱压力、摩擦力是造成既有结构隆起的主要原因,隆起量随土舱压力、摩擦力的增大而增大;3)盾尾脱离后既有结构沉降主要受注浆压力、摩擦力的影响,沉降量则随注浆压力的增大、摩擦力的减小而减小;4)与不考虑摩擦力的数值计算模型相比,考虑摩擦力的模型计算结果与工程实测数据吻合更好,且既有2号线运营地铁隧道结构变形满足规范所要求的控制标准,验证了研究成果的合理性与适应性。The friction is a crucial factor that affects the mechanical behavior of an existing structure induced by undercrossed shield tunnels.To investigate the influence laws of soil chamber pressure,grouting pressure,and friction on the deformation of existing tunnels and provide rational tunneling parameters,a friction calculation formula is deduced considering shield deadweight and soil pressure distribution characteristics.Then,the distribution law of friction is analyzed and the results are written into a finite difference software,FLAC 3D,through Fish language.Finally,a systematic study is conducted on technical parameters of shield tunneling underneath a metro tunnel and the feasibility is verified by field monitoring results.The results show the following.(1)The friction between shield shell and soil is unevenly distributed around the shield shell and the value increases with increasing friction angle,gravity,and tunnel depth.(2)In the process of shield tunneling,the vertical displacement of the existing structure first uplifted and then settled,soil chamber pressure and friction are the main reasons for the existing structure to be uplifted,and the uplifting increases with the increasing soil chamber pressure and friction.(3)Settlement of the existing structure is mainly affected by grouting pressure and friction after shield tail passes through,and the settlement decreases with the increase in grouting pressure and decrease in friction.(4)Compared with the numerical calculation model without considering friction,the calculation results of the model considering the friction agrees better with the engineering-measured data,and the structural deformation of the existing metro tunnel in the operation meets the control standards,which verifies the rationality and adaptability of the results.

关 键 词：盾构下穿 盾壳与土体摩擦力 盾构施工参数 变形监测 FLAC 3D 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]