| 摘要: |
| 【目的】分析增湿及剪切条件下黄土结构性的演化发展特性。【方法】在初始含水率为10%，15%，18%，22%，44%（饱和）以及固结围压为50，100，200，300 kPa条件下对黄土进行三轴剪切试验，测定并分析应力结构性参数、应力比结构性参数与综合应变的关系。【结果】黄土应力结构性参数和应力比结构性参数均能够反映出在整个应力加载过程中压剪作用对土结构性渐变演化特性的影响。但是在初始剪切阶段应力结构性参数的变化规律受试验条件的影响相对较大，在低固结围压、低含水率情况下，应力结构性参数随着综合应变的增加总体呈现出先上升后下降，之后趋于稳定的变化趋势；在固结围压及含水率较高的情况下，应力结构性参数随着综合应变的增加而逐渐减小。在增湿及剪切条件下，应力比结构性参数随综合应变的增加呈现单调衰减的趋势，且二者之间的关系曲线光滑，规律性较强；应力比结构性参数与综合应变之间呈指数函数关系。【结论】与应力结构性参数相比，应力比结构性参数能有效且完整地描述增湿和压剪应力作用下黄土结构性演化的整个过程。 |
| 关键词: 黄土 结构性 演化特征 增湿压剪 本构模型 |
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| 基金项目:国家自然科学基金项目（41272320）；贵州省自然科学基金项目（黔科合J字LKB［2012］13号）；贵州省教育厅自然科学重点项目（黔教合KY字［2013］179） |
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| Structural evolution of collapse loess under moisture and compression shearing stress |
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LUO Ai-zhong,SHAO Sheng-jun,FANG Juan,et al
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| Abstract: |
| 【Objective】This study analyzed the structural development process of collapse loess under moisture and compression shearing stress.【Method】The tri axial shearing tests of collapse loess were carried out with initial water contents of 10%,15%,18%,22%,and 44% (saturation),and confining pressures of 50,100,200,and 300 kPa.The stress structural parameter,stress ratio structural parameter and comprehensive strain were measured and their relationships were analyzed.【Result】The structural evolution of loess was reflected by stress structural parameter and stress ratio structural parameter.But stress structural parameter was significantly affected by experimental condition at the initial loading stage.When the pressure and water content were low,stress structural parameter increased firstly before decreasing to a stable level as the increase of stress.When the pressure and water content were high,stress structural parameter decreased as the increase of stress.Stress ratio structural parameter decreased as the increase of stress and the relationship curve was smooth with strong regularity.There was an exponential relationship between stress ratio structural parameter and compressive strain.【Conclusion】Stress ratio structural parameter provided a complete description of the throughout structural development process under moisture and compression shearing. |
| Key words: loess structural development evolution law moisture and compression-shearing constitutive model |
