增湿-减湿作用下黄土裂隙演化规律研究

发布时间：2018-03-28 23:18

本文选题：节理裂隙　切入点：增湿-减湿　出处：《工程地质学报》2017年02期

【摘要】：黄土内部存在各种裂隙,增湿-减湿作用导致原状黄土内部裂隙不断发展演化,因此研究在增湿-减湿作用下黄土裂隙发育演化规律具有非常重要的意义。以陕北延安地区某边坡黄土为研究对象,通过CT扫描技术获得了增湿-减湿作用下土样细观结构变化图,得到了土样CT数ME及SD值随土样增湿-减湿作用的变化曲线。研究结果表明:随着土体湿度的增加,土体内部损伤速率缓慢增加,当含水率超过土样塑限后,土体内部损伤速率加快,含水率超过一定值时,速度又减缓,CT数的均值和方差随含水率变化皆呈反"S"曲线;随着干湿循环次数的增加,土样微裂纹逐渐发育,表现为伸长变宽,呈不规则的分叉、甚至贯通;4次干湿循环后,土样裂隙裂缝基本成了网状,土样较破碎,此时CT数的均值和方差变化不大;干湿循环幅度越大,土样内部损伤程度也越大,土样内部节理裂隙发展也就越快。
[Abstract]:There are all kinds of cracks in loess. The effect of humidification and desiccating causes the internal cracks of undisturbed loess to develop and evolve continuously. Therefore, it is of great significance to study the development and evolution of loess fissures under the action of humidification and dehumidification. The microstructure changes of soil samples under the action of humidification and dehumidification were obtained by CT scanning technique, and the curves of soil CT number ME and SD value with soil sample humidification and moisture desiccation were obtained. The results showed that: with the increase of soil moisture, The internal damage rate of soil increases slowly. When the moisture content exceeds the plastic limit of soil sample, the damage rate of soil is accelerated, and when the moisture content exceeds a certain value, the mean value and variance of CT number slow down with the change of water content are all in inverse "S" curve. With the increase of dry-wet cycle times, the microcracks of soil samples develop gradually, showing that the microcracks of soil samples grow wider and become irregular bifurcations. Even after four dry-wet cycles, the cracks of soil samples are basically reticulated, and the soil samples are relatively broken. At this time, the mean and variance of CT number change little; the larger the range of dry and wet circulation, the greater the damage degree of soil sample, and the faster the development of joints and fractures in soil sample.
【作者单位】：西安科技大学建筑与土木工程学院;四川省眉山市彭山区住房和城乡规划建设局;
【基金】：国家自然科学基金项目(41672305,41172262) 陕西省重点科技创新团队计划(2014KCT-30)资助
【分类号】：P642.131

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