竖向压力作用下重塑黄土土柱压缩湿陷及渗水试验研究  

Experimental study on compression collapsibility and infiltration of remolded loess soil column under vertical pressure

作　　者：张林 张登飞 陈存礼[1] 游子龙 孙佩娜 ZHANG Lin;ZHANG Dengfei;CHEN Cunli;YOU Zilong;SUN Peina(Shaanxi Provincial Key Laboratory of Loess Mechanics and Engineering,Institute of Geotechnical Engineering,Xi’an University of Technology,Xi’an 710048,China;Department of Geology,Northwest University,State Key Laboratory of Continental Dynamics,Xi’an 710069,China;Shanghai zhongjian dongfu investment and development co.,LTD.,Shanghai 200120,China)

机构地区：[1]西安理工大学岩土工程研究所陕西省黄土力学与工程重点实验室,陕西西安710048 [2]西北大学地质学系大陆动力学国家重点实验室,陕西西安710069 [3]上海中建东孚投资发展有限公司,上海200120

出　　处：《水利学报》2019年第10期1214-1221,共8页Journal of Hydraulic Engineering

基　　金：中国博士后科学基金项目(2018M633559);延安大学校级科研项目(YDQ2019-33)

摘　　要：为了探讨竖向压力对兰州非饱和重塑黄土土柱压缩湿陷特性、入渗过程及土-水特征的影响,利用一维土柱渗透仪开展了不同竖向压力作用下非饱和重塑黄土土柱的常水头渗水试验,得到其压缩湿陷曲线,浸润峰、入渗量、体积含水量时程曲线与监测截面土-水特征曲线。研究结果表明:(1)土柱压缩性与湿陷性在试验压力下与常规试验皆有差异;尺寸效应不影响试验黄土结构强度,对其湿陷起始压力影响不大;(2)土柱增湿时浸润峰的前行速率随竖向压力的增大而逐渐减小;增湿过程中土柱在力与水作用下入渗能力变化导致入渗速率曲线有交叉现象,且竖向压力越大入渗速率变化范围越小;(3)竖向压力作用改变了渗水路径,从而影响了监测点体积含水率的变化;(4)竖向压力作用对土-水特征曲线的三个阶段均有影响,压力作用时土柱饱和度皆大于无压力作用,且随着压力增大饱和度逐步增大,当吸力趋于0时,土样未完全饱和。最后利用经典Van Genuchten模型对不同竖向压力下土-水特征曲线进行拟合,模型拟合效果较好。通过试验及分析,为兰州新区建设提供相关参考依据。In order to investigate the influence of vertical pressure on the compression and collapsibility characteristics,infiltration process and soil-water characteristics of unsaturated remolded loess soil in Lanzhou,the unsaturated remolded loess soil under different vertical pressures was developed by one-dimensional soil column permeameter, to obtain its time history curve of compression collapse curve, infiltration peak,infiltration capacity,volume moisture content and soil-water characteristic curve of monitoring cross section. The results show that:(1) The compressibility and collapsibility of soil column are different from the conventional tests under the test pressure;the size effect does not affect the structural strength of the test loess,and has little effect on the initial pressure of the collapse.(2) When the soil column is humidified,the forward rate of the infiltrating peak gradually decreases with the increase of the vertical pressure.During the humidification process,the infiltration capacity of the soil column under the action of force and water leads to a crossover phenomenon of the infiltration. rate curve,and the larger the vertical pressure is,the smaller the variation range of infiltration rate wall be.(3) The stress changes the seepage path,which affects the change of the volume moisture content at the monitoring point.(4) The vertical pressure has an effect on the three stages of the soil-water characteristic curve. When the pressure is applied,the soil column saturation is greater than the no-pressure effect,and the saturation gradually increases with the pressure increase. When the suction force reaches 0, the soil sample is not fully saturated. Finally, the classical van Genuchten model is used to fit the soil-water characteristic curves under different vertical pressures,and the model fitting effect is better. Through the test and analysis,it provides relevant reference basis for the construction of Lanzhou New District.

关 键 词：非饱和重塑黄土 竖向压力 尺寸效应 浸润峰 土-水特征曲线 

分 类 号：TU411[建筑科学—岩土工程]