随着我国城镇化进程的加快，为缓解日益增长的城市交通压力，改善城市环境，大直径隧道被广泛应用于城市交通建设当中。与传统的隧道开挖方法相比，盾构法具有施工速度快、对周围环境影响小、施工质量易于保证等优点。然而，在城市施工中大直径盾构隧道仍然面临着地质条件复杂、下穿危险区域多、与既有建筑物较近等危险因素。因此，研究大直径隧道盾构施工及其对周边设施的影响，可为此类工程的施工设计提供参考。本文首先依据对泰沙基活动门问题的数值模拟，进行土拱效应的相关机理研究。并在此基础上，建立了能反映盾构隧道施工工序的数值模型，对隧道盾构施工过程中盾壳所受的摩阻力大小以及盾构施工对周围土体变形的影响进行参数分析。最后针对一实际的盾构隧道工程项目进行数值模拟计算，为优化其设计方案提供参考意见。主要研究成果如下：1.对活动门问题进行数值模拟，得出在不同情况下泰沙基土拱理论的计算精度，为隧道工程的施工设计提供参考。并在此基础之上对影响活动门的成拱因素、活动门位移与其所受压力间的关系进行分析，为下一步研究做准备。2.建立了能反映盾构机向前掘进过程的数值模型，得出在体积损失率不同的情况下，覆土厚度、土体摩擦角、土体粘聚力和克泥效对盾壳所受摩阻力的影响。并根据数值模拟结果，从土拱效应、盾构机所受压力、盾壳与周围土体接触面的粗糙程度等角度分析各因素的影响机理。3.建立隧道盾构施工的数值模型，能够合理考虑隧道施工工序，并正确反映其对周边地层的影响。利用所建立的模型，进行包括覆土厚度、土体摩擦角、土体粘聚力、注浆压力、支护压力和体积损失率等影响因素研究，探究隧道盾构施工对其周围和地表土体的影响机理。4.针对北京城市副中心站综合交通枢纽工程，根据地勘数据和设计图纸，分别建立2D和3D数值模型进行计算，对设计方案进行了复核和优化。在原有设计方案中，计划在地下三层结构加盖中隔墙以减小下方隧道变形。根据计算结果，论证不需添加中隔墙，为施工方节省工程成本。

With the acceleration of urbanization in China, large-diameter tunnels have been widely used in urban transportation construction to alleviate the urban traffic pressure. Compared with traditional tunnel excavation methods, shield tunneling has the advantages of fast construction speed, minimal impact on the surrounding environment and easy guarantee of construction quality. However, in urban construction, large-diameter shield tunnels still face risks such as complex geological conditions, multiple dangerous areas to pass through and proximity to existing buildings. Therefore, studying the construction of large-diameter shield tunnel and its impact on surrounding buildings can provide reference for the construction design of such projects.In this paper, a study on the mechanism of soil arching effect was conducted by using numerical simulations based on the trap-door problem. On this basis, a numerical model that reflects the construction process of shield tunneling is established to analyze the frictional resistance of the shield shell during tunnel construction. It is also used to analyze the impact of shield construction on the deformation of surrounding soil. In the end of this paper, a numerical model which is based on an actual shield tunneling project is established to provide guidance for optimizing its design scheme. The main research achievements are as follows:1. Using Numerical simulations on the trap-door problem to determine the accuracy of Terzaghi soil arching theory under different conditions, providing a reference for the construction design of tunnel engineering. Based on this, an analysis was conducted on the factors affecting the formation of arches in the trap-door problem, as well as the relationship between its displacement and the pressure it receives, in preparation for further research.2. A numerical model that can reflect the forward excavation process of shield tunneling machines was established. The model was used to study the effects of the thickness of the overburden, soil friction angle, soil cohesion, and clay shock on the frictional resistance of the shield. The study also analyzed the mechanism of various factors from the perspectives of soil arching effect, pressure on the shield tunneling machine, and roughness of the contact surface between the shield and surrounding soil based on the numerical simulation results.3. A numerical model was established for tunnel shield construction, which can reasonably consider the tunnel construction process and accurately reflect its impact on the surrounding soil. Based on the obtained model, the influence factors, including the thickness of the overburden, soil friction angle, soil cohesion, grouting pressure, support pressure, and volume loss rate, were studied to explore the mechanism of the impact of tunnel shield construction on the surrounding and surface soil.4. Based on the transportation hub of Beijing sub-center station, 2D and 3D numerical models were established according to the geological exploration data and design drawings. The design scheme was reviewed and optimized. In the original design, it was planned to add partition walls in the three underground layers to reduce the deformation of the tunnel. According to the calculation results, it was demonstrated that there was no need to add partition walls, which could save construction costs for the construction party.