既有建筑对极软岩地层中土压盾构的施工影响

基于土压盾构在极软岩地层中近距离下穿既有建筑的背景，采用ABAQUS有限元数值模拟与现场实测相结合的方法，从地表和建筑物竖向位移变化及其控制的角度出发研究既有建筑对盾构施工的影响.实测结果表明:地表和建筑物在盾构下穿过程中会呈现出先隆起后沉降的趋势，其中在盾尾脱出阶段地表和建筑物会产生较大速率的沉降.数值模拟结果表明:建筑物改变了地层原有的应力场，使地表最终沉降峰值向靠近建筑物方向偏移并增大，沉降槽宽度也在一定程度上增大.本研究对于土压盾构穿越地层敏感区域具有较强的理论指导意义.同时，在工程实践方面，也对土压盾构采用施工参数调节与补强注浆来进行沉降控制提出了具体的指导方案. 

Influence of Existing Buildings on Construction of Earth Pressure Shield in Extremely Soft Rock Stratum

In this paper, based on the background of the earth pressure shield tunneling through the existing buildings in the extremely soft rock formation at a short distance, using the method of combining ABAQUS finite element numerical simulation and on-site monitoring, from the perspective of surface and building vertical displacement changes and their control, the impact of existing buildings on shield construction is studied. The actual measurement results show that the ground surface and buildings will show a trend of uplift first and then subsidence during the underpass of the shield. Among them, the surface and buildings will settle at a relatively large rate during the shield tail exit stage. Numerical simulation results show that the building changes the original stress field of the stratum, and the final settlement peak of the ground surface shifts and increases toward the direction of the building, and the width of the settlement trough is also increased in a smaller range. The research in this paper has a strong theoretical guiding significance for the earth pressure shield to penetrate the sensitive area of the formation. At the same time, in terms of engineering practice, a specific guidance plan for the use of construction parameter adjustment and reinforcement grouting for settlement control of the earth pressure shield is also proposed.