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盾构隧道施工引起的环境土工效应分析一直是城市轨道交通安全控制的关键课题。由于目前该领域较少考虑隧道衬砌与土体相互作用带来的影响,尤其是较少针对衬砌应力进行分析,由此提出带衬砌浅埋隧道开挖受非对称收敛变形影响的地层变形计算方法;同时考虑地层与衬砌之间的非对称收敛协调变形模式,建立带衬砌隧道开挖的Airy应力函数解析解答。通过实例研究,得到带衬砌隧道非对称变形模式下的地层沉降和水平位移曲线,并与实测数据进行对比验证;通过参数分析,获取土体和衬砌的材料特性、隧道几何特性以及隧道埋深等主要参数对浅埋隧道开挖地层变形和衬砌应力的影响规律。结果表明:非对称收敛变形模式对地层位移的影响明显,在此条件下得到的沉降槽和水平位移曲线与实测值吻合较好,地表最大沉降值更接近于实际;隧道半径或土层硬度对土体沉降最大值有较大影响,减小半径和硬化土层对减少土体沉降量效果显著,而衬砌几何参数的改变对沉降量的影响不大;衬砌轴力和弯矩整体关于90°/270°轴即隧道竖轴线严格对称,其中轴力沿圆周呈倒“8”字分布,而弯矩随着k值的增大,沿圆周方向由“8”字形向“0”字形过渡,最大轴压力和最大负弯矩发生在拱腰位置,土体侧压力系数k的取值对衬砌轴力和弯矩的分布和大小影响明显。分析成果可为正确预估软土浅埋盾构开挖变形提供一定的理论依据。
Environmental geotechnical analysis caused by shield tunnel construction has been a key issue in the safety control of urban rail transit. Because the influence of the interaction between tunnel lining and soil is rarely considered in this area, especially the lining stress is rarely analyzed, the calculation method of strata deformation caused by the asymmetric convergence and deformation of shallow tunnel with lining is proposed In the meantime, the non-symmetrical convergence and deformation modes between strata and lining are taken into account to establish the analytical solution of Airy stress function with tunneling. Through case study, the formation settlement and horizontal displacement curve under the asymmetrical deformation mode with lining tunnel are obtained and compared with the measured data. The material characteristics of the soil and lining, the geometric characteristics of the tunnel and the depth of the tunnel are obtained through parameter analysis Influence of Main Parameters on Formation Deformation and Lining Stress in Shallow Tunnel Excavation. The results show that the asymmetric convergence deformation mode has obvious influence on the displacement of the formation. The settlement groove and horizontal displacement curve obtained in this condition are in good agreement with the measured value, and the maximum settlement value of the surface is closer to the actual value. The tunnel radius or the hardness of the soil layer The maximum value of soil subsidence has a greater impact. Reducing radius and hardened soil have significant effect on reducing soil subsidence, while the change of lining geometric parameters has little effect on subsidence. The axial force and moment of lining are about 90 ° / 270 ° axis that is strictly symmetrical tunnel vertical axis, axial force along the circumference was inverted “8 ” word distribution, and bending moment with the k value increases along the circumferential direction from “8 ” to “ 0 ”, the maximum axial pressure and the maximum negative bending moment occur in the position of arch waist. The value of soil side pressure coefficient k has obvious influence on the distribution and size of lining axial force and bending moment. The results of the analysis can provide a theoretical basis for correctly estimating the deformation of shallow shield tunneling.