软土地基桶形基础循环累积变形研究

Cyclic accumulative deformation of bucket foundation on soft clay strata

针对软土地基桶形基础在循环荷载作用下的变形问题进行研究。首先,通过桶形基础循环模型试验获得在动、静荷载作用下地基的破坏特性。然后,从模型土池中取土样,进行不固结不排水(UU)循环三轴试验,测其循环累积应变特性,建立了累积应变与其相关因素间的关系。最后,采用有限元的方法模拟模型试验,将循环累积变形等效为蠕变,在理想弹塑性的基础上加入蠕变来计算循环荷载作用下桶形基础的变形,并与模型试验结果进行比较。结果表明,软土地基桶形基础在循环荷载作用下的变形与静力下的蠕变有相似的特点,桶形基础循环累积变形可以用等效为蠕变的方法计算。

The primary goal of this research is to solve the deformation problem of the bucket foundation on soft clay strata under cyclic load. Firstly, by cyclic model test, the failure characters of bucket foundation under static and cyclic load are studied. Secondly, unconsolidated undrained cyclic triaxial tests of the soil used in the model test are conducted under different static and cyclic loads to study characters of cyclic accumulative strains; and the relationship between strains and the relative factors is established. Finally, the model tests are simulated by using the finite element method. The cyclically accumulated deformation is equalized as a process of creep; and the deformation is calculated using ideal elastoplastic plus creep model. Then the calculated result is compared with the test result. It is concluded that the deformation of bucket of bucket foundation on soft clay strata under cyclic load is similar to the creep under static load, and the cyclic accumulative deformation can be calculated using this equalized method.