非饱和与饱和黄土统一性动力响应机制试验研究

发布时间：2018-01-26 15:38

本文关键词： 黄土饱和非饱和动荷载响应机制室内试验　出处：《兰州大学学报(自然科学版)》2016年05期 　论文类型：期刊论文

【摘要】：动荷载作用下,非饱和与饱和天然黄土在直观表现上显著不同,前者以震陷(动残余应变)为特征,后者则表现为液化现象.基于室内静(动)三轴试验、土水特征曲线测试,结合天然黄土的水、气两相在固相介质中的渗透性,研究固、水、气三相介质控制黄土应力响应过程的差异性作用,揭示天然黄土动残余应变与液化在动力响应机制上的统一性.试验分析结果表明:不同加载过程中,加载应力与残余变形、残余变形与孔隙压力的相关系数,普遍高于加载应力与孔隙压力的对应量值;相较固相介质响应外部荷载作用的变形过程,水、气两相的响应明显具有受限于固相介质变形的特征;固相介质的受载变形和水、气两相介质的低渗透性,是黄土动力响应过程中孔隙压力增长的决定性因素;非饱和与饱和黄土在直观现象上的差异,与水、气相在渗透性与可压缩性方面的显著差别密切关联.
[Abstract]:Under dynamic load, unsaturated and saturated natural loess are obviously different in visual performance, the former is characterized by earthquake subsidence (dynamic residual strain), while the latter is liquefaction, based on indoor static (dynamic) triaxial test. The soil-water characteristic curve test, combined with the permeability of natural loess water and gas in solid medium, studied the difference of stress response process controlled by solid, water and gas three-phase medium. This paper reveals the unity of dynamic residual strain and liquefaction of natural loess in dynamic response mechanism. The experimental results show that the correlation coefficient between loading stress and residual deformation, residual deformation and pore pressure in different loading processes. Generally higher than the corresponding value of loading stress and pore pressure; Compared with the deformation process of solid medium responding to external load, the response of water and gas phases is obviously limited by the deformation of solid medium. The loading deformation of solid medium and the low permeability of water-gas two-phase medium are the decisive factors for the increase of pore pressure in the dynamic response process of loess. The difference between unsaturated loess and saturated loess is closely related to the obvious difference in permeability and compressibility of water and gas phase.
【作者单位】：中国地震局兰州地震研究所;中国地震局(甘肃省)黄土地震工程重点实验室;兰州大学哲学社会学院;
【基金】：中国地震局地震预测研究所基本科研业务费专项(2013IESLZ01) 国家自然科学基金项目(51209186) 甘肃省科技计划项目(145RJZA152)
【分类号】：TU444
【正文快照】： 黄土属于一类第四纪沉积物黄土沉积时的地质营力、生成环境和物质来源等独特要素,形成了黄土多孔隙、弱胶结的显著结构特征[231.黄土结构特性使黄土表现出特有的工程地质特征与力学性质'在相关研究领域内黄土被归类为一种特殊土.现场考察和室内试验研究结果表明151:黄土极易在

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