长短桩复合地基沉降计算方法分析及探讨

Analysis and Discussion on Settlement Calculation Method of Long and Short Pile Composite Foundation

地基沉降计算在地基基础工程中存在着很大的难题。虽然许多研究在沉降计算方面付出了巨大的努力,但在计算精度上仍存在很大差异。现行的关于长短桩复合地基沉降理论一直处于摸索和发展之中。本文通过对等效天然地基法和加权模量法进行沉降计算,分析得出:(1)等效天然地基计算计算结果比较符合实际,加权模量法计算虽然比较简单,但是沉降计算的误差比较大。(2)加权模量法沉降计算中,桩体对褥垫层及下卧层都具有一定的刺入变形。针对刚性长短桩体在复合地基中的压缩模量计算没有考虑桩顶和桩底的刺入变形效应。而在实际工程中,仅由桩身压缩模量计算得到的复合模量和实际有很大误差,因而计算得到长短桩复合地基的沉降量很小,不符合实际需要,故本文提出一种方法对加权模量法计算方法进行改进,希望其有助于复合地基沉降计算的深入研究。

The foundation settlement calculation is a great problem in the foundation engineering. Although many studies have made great efforts in settling calculations, there are still significant differences in computa- tional accuracy. The existing theory of composite foundation settlement for long and short pile has been in the process of groping and developing. In this paper, the equivalent natural foundation method and the weighted modulus method are used to calculate the settlement. The results show that （ 1 ） The calculation results of the equivalent natural foundation are realistic, and the calculation of the weighted modulus method is simple, but the error of its settlement calculation is larger. （2） In the settlement calculation of the weighted modulus meth- od, the pile has a certain piercing deformation on the mattress layer and the layer under the floor. The calcula- tion of the compressive modulus of the rigid long and short pile in the composite foundation does not take into ac- count the piercing deformation effect of the pile top and the pile bottom. In the actual engineering, the compos- ite modulus calculated by the compressive modulus of the pile only has a great error. Therefore, it is calculated that the settlement of the composite foundation is very small and does not meet the actual needs. Therefore, this paper proposes a method that improves weighted modulus method, and it is hoped that it can help to the deep study on the calculation of composite foundation settlement.