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黄土震陷是地震发生时黄土地区发生的一种灾害。以典型马兰黄土(Q3)作为研究对象,对5组不同深度的原状黄土试样进行室内动三轴震陷试验,研究了该场地黄土震陷性随深度的变化特征。研究结果表明,(1)在天然含水率或是增湿、减湿情况下,黄土震陷深度曲线随动应力的增加均经历了一个从平稳、快速、再收敛至最大震陷深度的发展过程;(2)黄土震陷深度曲线的发展阶段动应力区间不尽相同,随着含水率的增加,黄土震陷快速发展期的动应力区间在变窄,最小动应力值变小,含水率20%条件下比5%最小动应力值可降低30%;(3)典型马兰黄土存在一个最大震陷深度,其最大震陷深度不受动应力、含水率影响,含水率仅能够降低达到最大震陷深度时最小动应力,加速黄土震陷深度的发展进程。在动应力不断增加的情况下,最终的黄土震陷深度曲线收敛于最大震陷深度,本次实验黄土场地的最大震陷深度约为15.5m。
Loess seismic subsidence is a kind of disaster occurred in the loess area at the time of earthquake. Taking the typical Malan loess (Q3) as the research object, five groups of undisturbed loess samples with different depths were tested for the dynamic triaxial vibration of the interior of the Loess Plateau. The characteristics of loess collapse with depth were studied. The results show that: (1) Under the condition of natural water content or humidification and dehumidification, the loess seismic depth curve has undergone a development from steady, rapid and re-convergent to maximum sinkage depth with the increase of dynamic stress ; (2) The dynamic stress range of loess subsidence depth curve is different during the development stage. With the increase of water cut, the dynamic stress range of the loess subsidence is narrowing and the minimum dynamic stress value becomes smaller. The water content is 20 (3) The maximum depth of subsidence in Malan loess is the largest, and the maximum depth of subsidence is not affected by dynamic stress and water cut, and the water cut can only decrease to the maximum The minimum dynamic stress in depth and the development of accelerating the depth of loess subsidence. Under the condition of increasing dynamic stress, the final loess seismic depth curve converges to the maximum seismic depth. The maximum depth of seismic collapse in this loess site is about 15.5 m.