Numerical Analysis on Load Carrying Mechanism of Single Pile Due to Twin Stacked Tunnelling

Abstract

AbstractIn recent years, the construction of twin tunnels in several populous cities increases significantly for better infrastructural development. In many situations, tunnel alignment must be laid below the high-rise buildings, bridges or important civil engineering structures. In such condition, the chances of detrimental effect on the foundations of these structures become very high. Hence, it is important to understand the tunnel–pile interaction mechanism for better safety and serviceability of these structures existing on the pile. In view of this series of numerical analysis are carried out on twin tunnel–pile interaction behaviour. It is observed that sequence of twin tunnel excavation gives significant effect on load carrying mechanism of pile. Two different tunnel excavation sequences are considered in the present study. In first sequence, first tunnel excavation is carried out near the mid-depth of pile and second tunnel excavation is carried out near the pile toe followed by the first one (ST). In second sequence, the excavation near the pile toe is carried out first and second tunnel excavation is carried out near the mid-depth of pile (TS). It is found that a sudden change in load bearing capacity is observed for first twin tunnels sequence (ST). Whereas, a smooth transition in load bearing capacity of pile is observed for second twin tunnel sequence (ST).KeywordsTunnelPileTunnel excavation sequenceLoad carrying capacity of pile