框架、筏基和土系统共同作用机理的探讨

本文采用不同的上部结构截面刚度,不同的筏基厚度和不同的有效应力弹性模量来探讨置于非均质土层上的筏基空间框架结构对共同作用分析的影响。通常,对置于非均质土层上筏基空间框架结构的共同作用分析需大容量的电子计算机,费用十分昂贵。本文采用了非常经济的简化方法。此简化方法是由金（King）和本文作者姚在英国“结构工程师”（The Structural Engineer）杂志一九八三年九月刊所介绍的。文中分析了一典型结构,得到了一些对设计非常有用的结论:第一,当上部结构的截面刚度改变时,对地基的沉降差影响很小,而对上部结构本身内力则影响很大。第二,适当改变筏基的刚度,对基础的沉降差和上部结构内力均有较大的影响。但不适当地增加过多,则影响很小,相反造成经济上的不合理。随筏基厚度的增加,筏基中的内力增加很大。第三,当土的有效应力弹性模量变化时,对建筑物的总沉降影响很大,但对上部结构和筏基中的内力及沉降差则影响很小。

An Assessment of the Effects of Structure/Raft/Soil Interaction

This paper is used to study the effects of interactive analysis of rafted framed structures founded on inhomogeneous soil by using different section moduli pf the superstructure, different raft thicknesses and different effective stress elastic mo duli of the soil.The interactive analysis of rafted framed structures founded on inhomogeneous soil media generally requires the use of a large computer, and is expensive. In this paper a much more economical simplified method to analyse these structures, which was developed by King and writer Yao in The Structural Engineer, September, 1983, is used. A typical long-rafted space frame is then analysed. Some intersting results which are very useful for design are obtained from the interactive analysis.First, when the relative section rigidities of the superstructure are varied by using different section sizes, the effects of the differential settements of the foundation are small. But the influence of the forces in the superstructure is significant.Secondly, when the relative rigidity of the raft is varied by using different raft thicknesses properly, both the effects of the differential settlements of the foundation and ths forces in the superstructure are significant. But for this type problem if the increasing of the raft thickness is too much, the effects are small and is expensive. However, the forces in the raft are varied significantly with the varying of the raft thickness.Thirdly, when the effective stress elastic moduli of the soil are varied, the effects of the total settlement of the building are significant. But the influence of the forces in the superstructure and raft and the differential settlements are small.