Underground transport infrastructure (tunnelling) plays a vital role to accommodate the rapid increase in urban population. Those tunnels are unavoidably constructed adjacent to high rising building supported by piled raft foundations which reduces differential settlements in the buildings. In this study, 3D numerical modelling using an advanced hypoplasticity soil model was carried out to investigate the responses of an existing (2 × 2) piled raft to twin stacked tunnelling at various depths. In each simulation, the first tunnel was constructed near the mid-depth of the pile shaft, the second tunnel was constructed either next to the toe of the piled raft (case ST), below but to one side of the piled raft (case SB) or directly beneath the pile toe (case SU). In addition, three more analyses were carried out to investigate the effects of change of construction sequence of twin stacked tunnels (i.e. cases TS, BS and US) on piled raft. The twin stacked tunnelling in case of SU caused the largest settlement but the smallest induced bending moment of the piled raft. On the contrary, the largest tilting of the pile raft took place in case SB. The first tunnel in each case caused the load transfer from the raft to the piles. On the contrary, the second tunnelling caused the increment in the load taken by the raft due to penetration of the raft into the ground. The different construction sequence of twin stacked tunnels had a substantial effect on settlement and tilting of the piled raft.

地下交通基础设施（隧道）在适应城市人口迅速增长方面发挥着至关重要的作用。那些隧道不可避免地与由桩筏基础支撑的高层建筑相邻，这减少了建筑物中的差异沉降。在这项研究中，使用先进的低塑性土壤模型进行了3D数值建模，以研究现有的（2×2）桩筏对不同深度的双桩隧道的响应。在每个模拟中，第一个隧道建在桩身中间深度附近，第二个隧道建在桩筏的脚趾附近（案例ST），在桩筏的下方（但在SB一侧）建造）或直接位于桩趾下方（案例SU）。此外，进行了另外三项分析，以研究双排隧道（即TS，BS和US情况）的施工顺序变化对桩筏的影响。在SU情况下，双排隧道引起最大的沉降，但引起的堆积筏的弯矩最小。相反，在SB情况下，发生了桩筏的最大倾斜。在每种情况下，第一条隧道都将载荷从木筏传递到桩上。相反，第二次隧穿由于筏子渗透到地面而引起筏子承担的载荷的增加。双排隧道的不同施工顺序对桩筏的沉降和倾斜有很大影响。在SU情况下，双排隧道引起最大的沉降，但引起的堆积筏的弯矩最小。相反，在SB情况下，发生了桩筏的最大倾斜。在每种情况下，第一条隧道都将载荷从木筏传递到桩上。相反，第二次隧穿由于木筏向地面的渗透而导致木筏承受的载荷增加。双排隧道的不同施工顺序对桩筏的沉降和倾斜有很大影响。在SU情况下，双排隧道引起最大的沉降，但引起的堆积筏的弯矩最小。相反，在SB情况下，发生了桩筏的最大倾斜。在每种情况下，第一条隧道都将载荷从木筏传递到桩上。相反，第二次隧穿由于筏子渗透到地面而引起筏子承担的载荷的增加。双排隧道的不同施工顺序对桩筏的沉降和倾斜有很大影响。第二次隧穿由于筏子渗透到地面而导致筏子承受的载荷增加。双排隧道的不同施工顺序对桩筏的沉降和倾斜有很大影响。第二条隧道由于木筏向地面的渗透而导致木筏承受的载荷增加。双排隧道的不同施工顺序对桩筏的沉降和倾斜有很大影响。