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为认识真空预压地基在真空压力卸载中的变形特性,对原状软黏土土样进行了常规三轴仪等向压缩与膨胀试验以及CKC三轴仪压缩膨胀试验,以模拟真空预压地基中各种应力状态下的土体单元在卸除真空压力这种球形压力后的变形特征。研究结果表明,真空压力卸载过程中地基土体既产生弹性的体积膨胀,因偏应力的存在,土体还产生剪切变形,在真空联合堆载预压中,堆载产生的较大偏应力将导致真空压力卸载时地基回弹很小,甚至地基继续沉降。真空压力卸载时,地基的沉降效果是土体膨胀变形和土体的剪切变形的叠加。
In order to understand the deformation characteristics of vacuum preloading foundation in vacuum pressure unloading, conventional triaxial compression and expansion test and CKC triaxial compression expansion test were carried out on the original soft clay soil to simulate the vacuum preloading Deformation characteristics of soils under stress state after removing spherical pressure under vacuum pressure. The results show that the soil in the process of vacuum pressure unloading not only produces elastic volume expansion, but also produces shear deformation due to the deviatoric stress. In the vacuum combined preloading, the large deviatoric stress Will lead to the foundation when the vacuum pressure unloading rebounds very small, and even the foundation to continue settlement. When the vacuum pressure is unloaded, the subsidence effect of the foundation is the superposition of soil expansion deformation and soil shear deformation.