盾构掘进对邻近桩基的变形特征研究

深圳地铁7号线盾构区间在YDK14+180~+280段进行近接桩基施工中,为了严格控制施工对近接桩基的扰动,以保证施工的安全性,通过有限元软件分析了不同掘进姿态在盾构施工过程中对近接桩基的影响。指出:1)盾构掘进姿态是施工过程中对近接结构物影响十分显著的因素,施工时应加以严格控制;2)在盾构蛇行推进过程中,随桩基与掌子面距离的减小和盾构蛇行偏角的加大,盾构施工掘进对桩基的影响程度在加大;3)在盾构刀盘推进至距离桩基间距为2.0D时,应严格控制盾构施工过程中的掘进姿态,特别需要控制盾构的左右偏离。

Study on Characteristics of Deformation of Adjacent Pile Foundations Caused by Shield Boring

From YDK14+180 to YDK14+280 of a running tunnel on Line 7 of Shenzhen Metro, the shield bores close to the existing pile foundations of a bridge. In the paper, the influence of different shield attitudes on the pile foundations is analyzed by means of finite element program, so as to bring the disturbance to the pile foundations under effective control and to ensure the tunneling safety. Conclusions drawn are as follows: 1) Shield attitude has great influence on the pile foundations, therefore shield attitude should be well controlled during tunneling; 2) As the distance between the shield and the pile foundations reduces and the shield rolling angle increases, the impact of shield boring on the pile foundations grows; 3) When the distance between the shield cutterhead and the pile foundation is twice the tunnel diameter, the rolling of the shield shall be strictly controlled.