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采用荷载-位移联合搜索方法,对于饱和软黏土地基上裙板式桶形基础在水平荷载H、力矩M与扭矩T的非共面复合加载条件下的稳定性进行了比较系统的三维有限元分析,主要探讨了在不同荷载空间内桶形基础的破坏包络轨迹。在分析中,地基土服从基于Tresca屈服准则的理想弹塑性本构关系。计算结果表明,与传统共面复合加载情况相比,非共面复合加载条件下桶形基础的破坏包络面形状有较大差异。非共面复合加载情况下,包络面形状不依赖于基础埋深比,可用简单的圆或椭圆方程进行描述。根据有限元计算结果,将已有的三自由度破坏包络面方程扩展到六自由度复合加载空间内,进而初步建议了一个六自由度破坏包络面方程,并对于实际工程中常用的桶形基础埋深比,给出了方程中偏心度参数取值的确定方法。该方程可用来合理评价复杂荷载条件下软黏土地基上桶形基础承载力。
A three - dimensional finite element analysis of the stability of the apron plate foundation on saturated soft clay foundation under the non - coplanar complex loading condition of horizontal load H, moment M and torque T was carried out using the load - displacement joint search method. This paper mainly discusses the destruction envelopment trajectory of bucket foundation in different load space. In the analysis, the subsoil obeys the ideal elastoplastic constitutive relation based on the Tresca yield criterion. The calculation results show that the shape of the failure envelope of the bucket foundation is different greatly under the non-coplanar compound loading condition compared with the traditional coplanar composite loading condition. In the case of non-coplanar complex loading, the shape of the envelope does not depend on the underlying depth-to-depth ratio and can be described by a simple circular or elliptical equation. According to the finite element calculation results, the existing three-degree-of-freedom failure surface equation is extended to the six-degree-of-freedom composite load space, and then a six-degree-of-freedom failure surface equation is initially proposed. In addition, Shape embedded depth ratio, given the value of the eccentricity of the equation to determine the value of the method. The equation can be used to reasonably evaluate the bucket foundation bearing capacity on soft clay foundations under complex loading conditions.