天然地基软弱下卧层顶面附加压力计算方法探讨

Discussion on Calculation Methods of Additional Stress on Top Surface of Weak Substratum under Natural Foundation

天然地基软弱下卧层承载力验算的关键,为下卧层顶面附加压力的计算。目前规范尚未明确1≤E_(S1)/E_(S2)<3时软弱下卧层顶面的附加压力计算方法,本文分别采用附加应力系数法和地基压力扩散角法(含叶戈罗夫理论解法、高大钊建议方法及地方规范提供方法),同时考虑了压缩模量比和计算深度的变化,对各计算方法下卧层顶面附加压力计算结果进行了分析对比,并给出1≤E_(S1)/E_(S2)<3时软弱下卧层顶面附加压力的计算方法建议。

The key point of weak underlying layer examination under natural foundation is the calculation of additional stress on top surface of weak substratum. At present, the additional stress coefcient calculation is not clear and defined if 1≤ES1/ES2〈3 in national standards, so this paper adopts two methods to calculate the stress coefcient as additional stress coefcient method and expansion angle of subgrade pressure methods （including Yegorov theoretical solution method, suggestion method by GAO Dazhao and local standards）, meanwhile considers changes of compression modulus ratio and depth, and analyzes and compares the calculating results from diferent calculation methods. The suggestions of additional stress calculation in the case of 1≤ES1/ES2 〈3 is provided.