武汉软土的卸荷应力—应变归一化特性研究

因土体卸荷引起的工程问题与一般土工加载问题表现的特性明显不同,目前对土的卸荷应力—应变归一化特性研究并不深入。开展不同固结压力与卸荷比的K0固结剪切试验,探究卸荷条件下软土的变形规律,重点研究卸荷条件下软土的应力—应变归一化特性。结果表明,武汉软土卸荷变形特性与卸荷应力路径以及卸荷比关系密切,其应力—应变关系成双曲线关系,具有较高的非线性与归一化特性,这也使得应用邓肯—张模型去描述土的卸荷特性成为可能,该研究对于改进工程设计计算具有重要意义。

Study on Stress-Strain Normalization of Soft Soil under Excavation Unloading in Wuhan Area

Excavation is a typical unloading process.The soil behavior under excavation unloading is obviously different from that under loading condition.The in-depth research on the characteristics of stress-strain normalization of soil has a long way to go.In this paper are presented the K0 consolidation shear tests under different consolidation pressures and unloading ratios,the deformation characteristics of soft soil under unloading conditions and the its stress-strain normalized relationship.The results show that in Wuhan area the soft soil deformation characteristics under unloading condition are closely related to the unloading path and unloading ratio.The stress-strain shows a hyperbolic relationship with high nonlinearity and normalized characteristics.It makes Duncan Chang model applicable to describe the unloading characteristics of the soil and is of importance to improve the engineering design and calculation.