先动后静荷载联合作用下结构性软粘土力学响应
发布时间：2019-06-26 11:31
【摘要】：为研究结构性软粘土在先动后静荷载作用下的力学响应特性,利用动静扭剪仪对天津滨海结构性软粘土进行了不同动应力幅值和波形的循环荷载作用,当动力累积塑性应变达到不同控制值后,再对土样进行静力三轴剪切试验。试验结果表明,在循环荷载作用下,累积塑性变形不断增大,土体结构破损加剧,随着先期动应力幅值和累积塑性应变的增大;之后,静力三轴应力应变关系曲线由应变软化型逐渐变为硬化型,其区分界限(1.25%)即为结构屈服应变;以结构屈服应变为分界点,相同围压下静力破坏应力随累积塑性应变的增大呈先快后缓的下降趋势。
[Abstract]:In order to study the mechanical response characteristics of structural soft clay under static load, the cyclic loading of Tianjin coastal structural soft clay under different dynamic stress amplitudes and waveforms was carried out by using dynamic and static torsional shearing apparatus. When the dynamic cumulative plastic strain reached different control values, the static triaxial shear test was carried out on the soil sample. The experimental results show that under cyclic load, the cumulative plastic deformation increases and the damage of soil structure intensifies, with the increase of the amplitude of initial dynamic stress and cumulative plastic strain, then the static triaxial stress-strain relationship curve gradually changes from strain softened type to hardened type, and its distinguishing limit (1.25%) is the yield strain of the structure. When the yield of the structure becomes the boundary point, the static failure stress decreases rapidly at first and then slowly with the increase of cumulative plastic strain under the same confining pressure.
【作者单位】： 天津城建大学土木工程学院;天津市软土特性与工程环境重点实验室;
【基金】：国家自然科学基金项目(41372291) 天津市科技计划项目(15JCZDJC40600,15ZCZDSF00220)~~
【分类号】：TU442
[Abstract]:In order to study the mechanical response characteristics of structural soft clay under static load, the cyclic loading of Tianjin coastal structural soft clay under different dynamic stress amplitudes and waveforms was carried out by using dynamic and static torsional shearing apparatus. When the dynamic cumulative plastic strain reached different control values, the static triaxial shear test was carried out on the soil sample. The experimental results show that under cyclic load, the cumulative plastic deformation increases and the damage of soil structure intensifies, with the increase of the amplitude of initial dynamic stress and cumulative plastic strain, then the static triaxial stress-strain relationship curve gradually changes from strain softened type to hardened type, and its distinguishing limit (1.25%) is the yield strain of the structure. When the yield of the structure becomes the boundary point, the static failure stress decreases rapidly at first and then slowly with the increase of cumulative plastic strain under the same confining pressure.
【作者单位】： 天津城建大学土木工程学院;天津市软土特性与工程环境重点实验室;
【基金】：国家自然科学基金项目(41372291) 天津市科技计划项目(15JCZDJC40600,15ZCZDSF00220)~~
【分类号】：TU442
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