【摘要】 地铁施工过程中盾构下穿上部已支护的基坑,将会对其支护结构及周边土体产生影响作用,因此有必要在盾构下穿前采用数值模拟的方法进行基坑稳定性分析。采用FLAC^3D软件模拟盾构下穿基坑后,青岛滨海软土区土体和地下连续墙的受力和变形情况,分析不同的下穿深度对基坑的底板沉降造成的影响。研究表明,盾构下穿基坑后底板附近的横向位移较大并成一定角度斜向上对称扩展至地表面,这些部位施工时应注意加固。在一定范围内,基坑底板的沉降量随着盾构形心与地表之间的竖向距离的增大而减小。本项研究成果可以为盾构下穿基坑时土体和支护结构的变形控制以及选择盾构下穿的深度提供一定依据。更多还原

【Abstract】 In the process of subway construction, shield tunneling pass under the supported foundation pit will affect its supporting structure and surrounding soil. Therefore, it is necessary to use numerical simulation method to analyze the stability of foundation pit before shield tunneling pass under. In this paper, FLAC^{3 D} software is used to simulate the stress and deformation of soil and diaphragm wall in Qingdao coastal soft soil area after shield passing under the foundation pit, and the influence of different depth of shield driving on the floor settlement of foundation pit. The results show that the transverse displacement near the foundation pit floor is large after shield tunneling through the foundation pit and extends symmetrically to the surface obliquely and upward, so the reinforcement should be paid attention to in the construction of these parts. The settlement of the foundation pit floor decrease with the vertical distance between the shield center and the ground in a certain range. The results of this study can provide a basis for controlling the deformation of soil and supporting structure and selecting the depth of shield tunneling when shield tunneling passing under the foundation pit.更多还原