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结合苏锡常地区地面沉降研究,用单向固结仪研究饱和黏性土在复杂荷载作用下的蠕变变形特征。试验土样取自苏锡常地区第2弱透水层。研究结果表明,在初次加载时黏性土具有明显的蠕变性,在双对数坐标中蠕变变形与时间呈直线关系,且直线斜率随荷载水平增大而减小,但在荷载水平达到一定值后斜率变化不大;在初次卸载时黏性土仍有明显的回弹蠕变,特别是在卸载水平较高时,卸载回弹蠕变变形与应力和时间的关系仍可用幂函数表示;在循环荷载作用下,加卸载达到变形稳定的时间随循环次数增加而减小。当循环荷载最大值小于土样的先期固结压力时,土样在2次加卸载循环后达到弹性变形状态;当循环荷载最大值等于土样的先期固结压力时,土样在5次加卸载循环后达到弹性变形状态。
Based on the study of land subsidence in the areas of Suzhou, Wuxi and Changzhou, the creep deformation characteristics of saturated cohesive soils under complicated loads are studied by a one-way consolidation method. The soil samples were taken from the second weakened aquifer in the Suzhou-Wuxi-Changzhou area. The results show that the clay has obvious creep during initial loading, the creep deformation in double logarithmic coordinates has a linear relationship with time, and the slope of straight line decreases with the increase of load. However, when the load reaches After the first unloading, the slope still has obvious rebound creep. Especially when the unloading level is high, the relationship between unloading rebound creep deformation and stress and time can still be expressed by power function Under the cyclic loading, the time of loading and unloading reaching the stable deformation decreases with the increase of the number of cycles. When the maximum cyclic loading is less than the pre-consolidation pressure of soil sample, the soil sample reaches the elastic deformation state after 2 loading-unloading cycles. When the maximum cyclic loading is equal to the consolidation pressure of soil sample, Unloading cycle to achieve elastic deformation.