吸力式沉箱组合基础承载特性研究

摘要

Based on the application background of the suction caisson foundation in bridge engineering, a numerical simulation method is used to investigate the bearing performance of the combined suction caisson foundation,and the number and spacings of caissons are considered. The effort is focused on the difference of bearing performance between the combined foundation and the single foundation, and on the contributions of connecting roofs to the bearing capacity of foundation.The analysis results show that the load?displacement curves of the combined caisson foundation are the same as those of the single caisson foundation. Similar to the pile group effect,the vertical bearing capacity of the caisson cannot be fully utilized in the combined foundation. Due to the contribution of the connecting roof between caissons, the vertical bearing capacity of the combined foundation will be greater than the sum of the corresponding numbers of the single suction foundation under a large caisson spacing, and it increases with the increasing caisson spacing. The lateral bearing capacity of the combined foundation is greater than the sum of the corresponding numbers of single suction foundation,and the contribution of connection roof can be neglected.%基于吸力式沉箱基础应用于桥梁工程的背景,考虑不同数量的沉箱组合和沉箱间距,通过数值模拟的方法研究了吸力式沉箱组合基础的承载特性,重点分析了组合基础与单个基础承载性状的差异,以及连接各沉箱的顶板对基础承载力的贡献.计算结果表明,沉箱组合基础与单个沉箱基础的荷载-位移曲线类型都相同;受类似于"群桩"效应的影响,竖向荷载作用下组合基础中的沉箱承载力不能完全发挥,但由于沉箱之间的连接顶板可以提供阻力,所以当沉箱间距较大时组合基础的承载力会大于相应数量单个基础的承载力之和,且随着沉箱间距的增大而增大;对于水平荷载作用下的吸力式沉箱组合基础,其承载力大于相应数量单个基础的承载力之和,连接顶板底部与土体之间的摩擦和挤压对于组合基础承载力的提高可以忽略不计.