浅埋圆形基础竖向地基承载力极限分析上限解

Upper-bound Limit Analysis of the Vertical Bearing Capacity of Circular Shallow Foundations

圆形基础是一种应用广泛的基础形式,而目前基础承载力研究主要集中在条形基础上,对圆形基础研究较少.针对现有圆形基础承载力求解方法中存在的问题,构建了多块体离散破坏模式,同时考虑土体自重、黏聚力及边载因素,求得竖向极限承载力的上限解表达式,并编制了最优化计算程序.将计算结果与已有的滑移线解、上限解、Hansen解以及工程实测资料进行广泛比较,证明该处计算浅埋圆形基础承载力的方法是更加准确合理的.然后根据计算结果分析了圆形基础地基滑裂面特性,发现由于同时考虑了土体重度,计算得到的地基滑裂面范围小于经典的对数螺旋滑裂面,滑裂面范围随内摩擦角的增大而增大,随重度增加而减小,随基础埋深的增大而增大.

The circular foundation is one of the most widely used foundation types. However, little emphasis has been placed on the research of the bearing capacity for circular shallow foundations than strip footings. To solve this problem, an upper-bound solution of the bearing capacity of circular shallow foundations was presented on the basis of the limit analysis by building a multi-block discrete model and taking soil weight, cohesion, and overload into account. Then, the present solutions have proved more accurate through comparisons with measured values found in references and calculation results using other meth- ods. Additionally, analyses of the ground slide surface were carried out, which show that the scope of the slide surface searched is smaller than that of the classical logarithmic spiral surface, due to the weight of the soil. The scope of the slide surface increases with the increase of internal friction angle and embedded depth, but decreases with the increase of the unit Weight of soil.