为研究大直径盾构隧道近穿及下穿对填土地基中桩基的扰动影响,依托某大直径盾构隧道工程,结合FLAC3D数值软件,对大直径盾构隧道近穿及下穿对桩基础的位移特征及承载力特性进行模拟分析.分析结果表明:盾构近穿及下穿过程中,对桩基础的位移及沉降存在扰动影响,其中盾构到达前10 m和通过后12 m范围,对桩基沉降影响较大,盾构近穿桩基时,桩基沉降速率较大,盾构下穿桩基时,盾构靠近桩基前20 m,桩基沉降速率变大,通过桩基后,桩基沉降趋于平缓.随着盾构的掘进,桩基靠近隧道处侧摩擦阻力波动较大,且隧道正上方的桩侧负摩阻力增大,易导致建筑物沉降.%In order to study the influence of the large diameter shield tunnel close and under pass through the pile foundation.Based on a large diameter shield tunnel project,combined with the FLAC3D numerical software,the displacement characteristics and bearing capacity characteristics of the large diameter shield tunnel in the near and under the pile foundation are analyzed numerically.The results show that the displacement and settlement of the pile foundation are affected by the deformation of the shield in the process of the shield tunneling and the tunneling,and the influence of 12m on the settlement of pile foundation is greater when the shield reaches 10m before and after passing through,when the shield close pass through the pile foundation,the pile foundation settlement rate is bigger,when the shield under pass through the pile foundation,the shield is close to the 20m of the pile foundation,and the settlement rate of the pile foundation becomes larger.With the shield tunneling,the friction resistance of the pile side near the tunnel is very large,and the negative friction resistance of the pile on the top of the tunnel will increase,which will lead to the settlement of the building.
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