基于有限元数值模拟的盾构施工对地表沉降的参数影响分析

Analysis of Influence of Shield Tunnel Construction on Ground Settlement Parameters Based on Finite Element Numerical Simulation

以实际工程为背景,采用有限元数值方法探讨了隧道埋深、掘进压力、应力释放系数等因素对地表沉降的影响.分析中采用控制变量法,将单因素取合理范围内不同参数进行数值模拟和结果对比分析,研究各因素在不同值域对地表沉降的影响程度.结果 表明,随着隧道埋深的增加,地表沿隧道纵、横向位移极值均逐渐减小,沉降曲线的曲率随之减小;盾构掘进压力对隧道掘进施工过程产生的地表沿隧道纵向位移影响较大,对横向位移影响较小;盾尾注浆的及时性对于地表位移影响较大,未注浆条件下地表位移沉降远大于其他情况,注浆的强度对于地表位移影响相对较小;随着刀盘与盾尾刷之间岩土体应力释放系数的增加,地表沿隧道纵、横向位移均逐渐增加.

Based on the practical engineering,the finite element numerical method is used to explore the influence of factors such as the depth of the tunnel,the heading pressure,and the stress release coefficient on the ground settlement.In the analysis,the control variable method is used.Different parameters within a reasonable range are taken for single factor for numerical simulation and comparative analysis of results.The degree of influence of each factor on surface settlement in different value ranges is studied.The results show that as the depth of the tunnel increases,the extreme values of the longitudinal and lateral displacements of the surface along the tunnel gradually decrease,and the curvature of the settlement curve decreases accordingly.The impact on the longitudinal displacement of the surface caused by the tunneling pressure during the tunneling process is greater than that of the lateral displacement.The timeliness of grouting at the shield tail has a greater impact on surface displacement.The surface displacement settlement under the condition of no grouting is much greater than other cases,and the strength of grouting has relatively small impact on surface displacement.As the stress release coefficient of the rock and soil between the cutter head and the shield tail brush increases,the longitudinal and lateral displacements of the ground surface along the tunnel gradually increase.