循环荷载下温州超固结软土动强度与变形分析

Analysis of dynamic strength and deformation of Wenzhou overconsolidated soft clay under cyclic loading

通过循环三轴试验对循环荷载作用下温州超固结软粘土的动力特性进行了研究。重点分析正常固结、轻超固结和强超固结软粘土在循环荷载作用下动应力、孔压及轴应变随循环次数变化的规律。研究结果表明,循环荷载作用下超固结软粘土将产生负孔压。对于轻超固结软粘土,负孔压将发生转向;而对于强超固结软粘土,孔压始终向负孔压方向发展。随着超固结比的增大,土体的动应变累积速度减慢,转折应变随之减小,而临界循环应力比随之增大。随着超固结比的增大,土体的动强度增加。与正常固结比相比,超固结软粘土的动强度曲线更平缓,强度衰减速率更小。

The dynamic behavior of Wenzhou overconsolidated soft clay under cyclic loading was studied by cycli triaxial tests. The change oi dynamic stress, pore water pressure and strong overconsolidated soft clay with oyclic number were investigated respectively. It is observed that negative pore water pressure is generated for overconsolidated clay under cyclic loading. For light overconsolidated clay, the negative pore pressure turns positive with the increase of cyclic number. However, for strong overconsolidated clay, the pore pressure is always negative. The dynamic strain of the clay accumulates more slowly, turning strain decreases, critical cyclic stress ratio and dynamic strength increase along with the increase of overconsolidated ratio. Compared with normal consolidated clay, the dynamic strength curves of overconsolidated clay are smoother with a less degradation rate.