干湿循环条件下干燥应力历史对粉质黏土饱和力学特性的影响

发布时间：2018-05-15 22:29

本文选题：干湿循环 + 干燥应力　；参考：《水利学报》2017年02期

【摘要】：以大连地区典型粉质黏土为研究对象,对经历不同干燥应力历史的粉质黏土试样在饱和条件下进行了固结不排水三轴剪切试验。通过对各组试样固结不排水剪切试验的应力-应变关系、孔隙水压力和有效应力路径等试验结果的对比分析,探讨了干燥应力历史对粉质黏土饱和力学特性的影响。固结不排水三轴剪切试验结果表明:干湿循环过程中粉质黏土在饱和条件下的力学特性变化与历史干燥应力有关,历史干燥应力越大,土体在饱和条件下的力学特性变化越明显。相同围压条件下,干湿循环试样的初始剪切刚度比未经历干湿循环的原始试样要高,历史干燥应力越大,初始剪切刚度增长越明显。随着历史干燥应力的增加,干湿循环试样的应力-应变曲线逐渐由应变硬化转变为应变软化,孔隙水压力的发展由先增加后减小转变为孔压持续增长,有效应力路径逐渐由"S"型转变为向左下方发展。干湿循环过程引起了土体的不可逆体积压缩和微裂隙的发展,进而影响土体的饱和力学特性。
[Abstract]:The undrained triaxial shear tests of silty clay samples with different drying stress histories were carried out under saturated conditions. The effects of drying stress history on saturated mechanical properties of silty clay were investigated by comparing the stress-strain relationship pore water pressure and effective stress path of undrained shear tests. The results of undrained triaxial shear test show that the mechanical properties of silty clay under saturated conditions are related to the historical drying stress, and the greater the historical drying stress is, The change of mechanical properties of soil under saturated condition is more obvious. Under the same confining pressure, the initial shear stiffness of the dry-wet cycle sample is higher than that of the original sample without dry-wet cycle. The greater the historical drying stress, the more obvious the increase of initial shear stiffness. With the increase of historical drying stress, the stress-strain curve of dry-wet cycle samples gradually changed from strain hardening to strain softening, and the development of pore water pressure changed from first increasing and then decreasing to continuous increase of pore pressure. The effective stress path gradually changed from "S" type to the lower left side. The process of dry and wet circulation causes the irreversible volume compression and the development of micro-cracks in soil, thus affecting the saturated mechanical properties of soil.
【作者单位】：江南大学环境与土木工程学院;大连理工大学海岸与近海工程国家重点实验室;
【基金】：国家自然科学基金项目(41572252,51609102) 大连理工大学海岸与近海工程国家重点实验室开放基金(LP1613)
【分类号】：TU442

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