原状黄土增湿过程中的静止土压力系数变化规律试验研究

发布时间：2018-05-22 11:03

本文选题：湿陷性黄土 + 静止土压力系数　；参考：《工程科学与技术》2017年05期

【摘要】：目前得到的湿陷性黄土静止土压力系数K_0,无法反映应力和含水两个因素的影响。本文开展了原状黄土增湿过程中K_0变化规律的试验研究,得到了力水耦合作用下K_0的计算方法。首先引入"增湿水平"这一概念描述土体的含水状态;开展竖向压力作用下的侧限分级浸水试验,分别研究增湿水平、基质吸力、竖向应变与K_0的相关关系;开展黄土湿陷的离心模型试验,验证室内试验结论的有效性。试验结果表明:"增湿水平"物理意义明确,能够反映土体的含水率初始情况和增湿过程;原状黄土K_0随着增湿水平的增大而线性增加,增加速率取决于竖向压力的大小,竖向压力越大增加速率越慢;增湿过程中K_0随着吸力的减小而线性增加,竖向压力越大K_0增加的速率越慢,与增湿水平对K_0的影响规律相似;不同竖向压力下增湿过程中的竖向应变与静止土压力系数K_0试验点分布在一个较窄的范围内,可以采用同一双曲线描述,且不同压力作用与浸水作用的先后次序对曲线影响较小。基于上述新疆伊犁黄土试验规律,建立以增湿水平和竖向压力为自变量的K_0的表达式,以及以竖向应变为自变量的K_0的表达式。
[Abstract]:The static earth pressure coefficient K _ 0 of collapsible loess can not reflect the influence of stress and water content. In this paper, the experimental study on the variation of K _ 0 during the humidification of undisturbed loess is carried out, and the calculation method of K _ 0 under the action of coupling force and water is obtained. Firstly, the concept of "humidification level" is introduced to describe the water state of soil, and the lateral limit step immersion test under vertical pressure is carried out to study the correlation between humidification level, matrix suction, vertical strain and K0, respectively. The centrifuge model test of loess collapsibility was carried out to verify the validity of the conclusion of laboratory test. The experimental results show that the physical meaning of "humidification level" is clear and can reflect the initial moisture content of soil and the humidification process, and the increase rate of the undisturbed loess K _ 0 increases linearly with the increase of the humidification level, and the increase rate depends on the vertical pressure. In the process of humidification, K _ 0 increases linearly with the decrease of suction, and the increase rate of K _ S _ 0 is slower with the increase of vertical pressure, which is similar to the effect of humidification level on K _ 0. The vertical strain and static earth pressure coefficient K _ 0 are distributed in a narrow range during humidification under different vertical pressures, which can be described by the same hyperbolic curve. The order of pressure and soaking has little effect on the curve. Based on the above experimental rule of loess in Yili, Xinjiang, the expressions of K _ s _ 0 with humidification level and vertical pressure as independent variables and K _ 0 with vertical strain as independent variables are established.
【作者单位】：中国水利水电科学研究院;西北农林科技大学水利与建筑工程学院;
【基金】：国家自然科学基金资助项目(51379220;51279171;51679264)
【分类号】：TU444

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