中文摘要：

针对桩筏基础等刚度设计条件下普遍存在的＂碟形沉降＂现象,从变形控制角度出发,将筏底桩体视为非线性弹簧,采用单桩载荷试验所得Q-s曲线作为弹簧刚度,建立了桩筏基础简化分析模型.通过数值模拟手段,采用平面变刚度、竖向变刚度和空间变刚度三种设计方法降低筏板基础的差异沉降,比较分析了桩筏基础均布荷载下各种设计方法的沉降特征.结果表明桩筏基础的空间变刚度可有效减小基础差异沉降,改善基础受力变形特征,并降低材料用量,技术经济效益显著.

英文摘要：

The dish-shaped settlement curves are often induced in piled raft foundations.For reducing the differential settlement occurring in this kind of foundations,a simple numerical simulation model is presented in this paper.In this model,piles are treated as springs and the stiffness of the piles is decided according to the Q-s curves of capacity test.To decrease the differential settlement,three analysis methods are employed,which are horizontal variable-stiffness design method,vertical variable-stiffness design method and dimensional variable-stiffness design method.Comparisons about settlement are made between the equivalent-stiffness design method and other variable-stiffness design method.The results indicate that the dimensional variable-stiffness design method is effective to reduce the differential settlement and to economize the building materials consumed.