Mechanical characteristics and isolation effects of isolated piles due to side loading

Based on the settlement control of the immersed tube tunnel of Hong Kong-Zhuhai-Macao Bridge, laboratory model tests are performed to study the bearing behaviors and isolation effects of isolation piles under a large side loading in the island edge. The results show that the mechanical properties of isolation piles are similar to typical characteristics of passive piles, and the maximum bending moment for isolation piles becomes larger as the length increases. The maximum axial force of the adjacent piles decreases by 10.5% under each level of side loading due to the isolation effects of isolated piles. At the same time, the maximum positive and negative bending moments decrease by 20% and 25%, respectively. The decreasing degree for the maximum axial force of the adjacent piles decreases as the length of isolation piles increases. However, the decreasing degree for the maximum positive bending moment of the adjacent piles is enhanced by the increasing length of isolation piles. The isolation effects become more outstanding as the lengths of isolation piles increase.