基础沉降与其尺寸非线性关系的有限元分析

Analysis of nonlinear relationship between foundation settlement and its dimension by finite element method

现行规范根据载荷试验确定地基承载力时所依据的是线性变形理论,沉降计算结果与工程实际颇有不符,导致承载力使用的保守.对中、低压缩性的砂性土和黏性土2种地基进行了变直径的非线性数值模拟计算与分析.结果表明,随着基础宽度B的增大,基础沉降s非线性地增大,并逐渐趋于平缓,沉降宽度比s/B快速减小并趋于0,表现出显著的非线性.此外,还给出了考虑荷载水平的拟合公式,并结合工程实例,验证了其正确性.

In current codes, the basis according to which the subgrade bearing capacity is determined by plate loading test complies with linear deformation theory. The calculated settlements are always not agreed with those measured in engineering practice. The ground bearing capacity cannot be fully estimated. For sandy soil and clay loam with low or medium compressibilities the foundtions were calculated and analyzed by diameter-variable nonlinear numerical simulation. The conclusion is that foundation settlement s will nonlinearly increase with increase of the foundation width B , and tend towards constance, and settlement-width ratio s/B will reduce rapidly and tend to zero finally. It is a nonlinear relation. Moreover, a fitting equation according to load level was proposed, then verified by engineering practice, the equation can be used in practice.