（南京军区建筑设计院 210029）
【提要】在进行天然地基上浅基础的设计时，必须验算地基承载力。如果存在软弱下卧层，还必须进行软弱下卧层承载力验算。根据《建筑地基基础设计规范》（GB50007—2002）中关于地基承载力计算及软弱下卧层承载力验算的相关规定，推导出一种可直接计算出满足要求的基础底面积的简便计算方法。运用该方法可准确地求出基础底面积而不必反复验算。
【关键词】 基础底面积  地基承载力  软弱下卧层
Simple Method to Determine Base Area of Natural Subgrade with Soft Substratum/Zhao Yanqiu，Bao Yuming (Nanjing Military Area Architecture Design Institute, Nanjing 210029, China)
Abstract:In the design of shallow foundation, the checking computation of the subgrade bearing capacity must be conducted. If there exists soft substratum, the checking computation of the soft substratum bearing capacity must be conducted. Based on the calculation rule of subgrade bearing capacity and verification of soft substratum bearing capacity in Code for design of building foundation (GB50007—2002), a simple method to determine the bottom area of foundation innatural subgrade is presented. The bottom area of foundation is calculated accurately with this method,and the trialcalculation is not needed.
Keywords:base area;   subgrade bearing capacity;  soft substratum