基于蠕变试验的路基压实黄土流变本构模型研究

发布时间：2019-01-02 08:27

【摘要】：结合具体试验路段,运用载荷装置与高压固结仪对不同能级强夯条件下的压实黄土进行蠕变试验,探讨压实度和含水量对压实黄土结构屈服强度的影响,建立可反映压实黄土流变特性的本构模型。研究结果表明:在蠕变应力小于土体的结构屈服强度时,地基土体主要表现为衰减蠕变;蠕变应力大于土体的结构屈服强度时,其蠕变类型主要表现为稳定蠕变;当蠕变应力远大于土体的结构屈服强度时,其蠕变类型主要表现为加速蠕变。一维高压固结条件下土样的塑性残余变形与含水量近似呈线性关系,压实度和含水量与结构屈服强度呈指数关系。原状黄土的回滞环形态上呈狭窄的条形,而压实黄土则呈新月形;载荷试验条件下压实黄土不同阶段分别表现为线性黏弹性和非线性黏塑性流变特征,可建立压实黄土流变本构模型反映其应力应变基本规律。
[Abstract]:The creep tests of compacted loess under different energy levels of dynamic compaction are carried out by means of loading device and high pressure consolidation instrument combined with concrete test section. The effects of compaction degree and water content on yield strength of compacted loess structure are discussed. A constitutive model reflecting the rheological characteristics of compacted loess was established. The results show that when the creep stress is smaller than the yield strength of soil, the creep of foundation soil is mainly attenuated creep, and when the creep stress is greater than the structural yield strength of soil, the creep type is mainly stable creep. When the creep stress is much greater than the yield strength of soil, the creep type is mainly accelerated creep. Under the condition of one dimensional high pressure consolidation, the plastic residual deformation of the soil sample is approximately linear with the water content, and the compaction degree and water content are exponentially related to the yield strength of the structure. The hysteresis loop of the undisturbed loess is narrow in shape, while the compacted loess is in the form of a crescent. Under the loading test conditions, the different stages of compacted loess show linear viscoelastic and nonlinear viscoplastic rheological characteristics respectively. The rheological constitutive model of compacted loess can reflect the basic laws of stress and strain.
【作者单位】：陕西铁路工程职业技术学院铁道工程系;
【基金】：陕西省教育厅自然专项科研计划项目(16JK1171) 陕西铁路工程职业技术学院科研基金资助项目(STY2015-09)
【分类号】：U416.1

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