Tunnelling activity inevitably induces change of soil stress and hence may cause adverse effects on nearby pile foundations. In this study, a three-dimensional centrifuge model test and a series of numerical analyses were carried out to investigate the effects of pile group in clay due to twin tunnelling in different depth. The springline of twin tunnels in the test were located at half a tunnel diameter above the pile toe (Test FF). Numerical back-analysis of centrifuge model test and parametric study were also carried out to get more insight of twin tunnels-pile interaction. Two more configurations, i.e., twin tunnels located at mid-depth of the pile (Simulation MM) and below the pile toe (Simulation BB), were investigated in the numerical analyses. The relative elevation between the twin tunnels and pile group has a significant effect on the pile settlement and the pile bearing capacity. Apparent loss of the pile bearing capacity (i.e., 90.2%) and the largest pile settlement (i.e., 5.5% of pile diameter) due to twin tunnelling are identified in Simulation BB. The maximum value of the loss of the pile bearing capacity was 2.7 times of the minimum value (Simulation MM). Additionally, the maximum transverse tilting of pile group induced by twin tunnelling is also observed when C/D = 3.7 (i.e., Simulation BB).
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机译：隧道活动不可避免地诱导土壤压力的变化，因此可能对附近的桩基产生不利影响。在该研究中，进行了三维离心机模型测试和一系列数值分析，以研究不同深度的双隧道引起的粘土中桩基的影响。测试中的双隧道的弹跳线线位于桩脚趾上方的隧道直径（测试FF）上。还进行了离心机模型试验和参数研究的数值背分析，以获得对双隧道桩相互作用的更多洞察力。在数值分析中研究了两种更多的配置，即位于桩中深度（模拟mm）和桩脚趾下方的双隧道（仿真BB）。双隧道和桩基之间的相对升高对桩沉降和桩承载力具有显着影响。在模拟BB中鉴定了由于双隧道引起的桩承载力（即90.2％）和最大桩沉降（即5.5％的桩直径）的表观损失。填充能力损失的最大值为最小值的2.7倍（仿真mm）。另外，当C / D = 3.7（即，仿真BB）时，还观察到由双隧道沟引起的桩基的最大横向倾斜。
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