川西非饱和混合土土水特征曲线研究
发布时间：2018-10-17 20:42
【摘要】：川西地区地质构造和气候条件复杂,交通荷载和降水入渗经常会引发处于非饱和状态的混合土公路路基变形过大或滑坡破坏,非饱和土的工程性质主要与其吸力值紧密相关。为掌握川西非饱和混合土矿物成分与初始干密度对其土水特征曲线的影响规律,针对川西山区3种崩坡积混合土,采用滤纸法和压力板仪法相结合的试验方案,缩短试验时间,测得各自在不同初始干密度下的土水特征曲线,并通过微观特征来分析宏观现象,探究混合土特征因素的影响机理。试验结果表明:矿物成分对土水特征曲线有显著影响,亲水矿物含量越高,基质吸力越大且曲线走势越平缓;反之,含有较多石英矿物和较少黏粒时,基质吸力通常较低;在相同基质吸力条件下,干密度越大,土体含水量也越大;同时,干密度对土水特征曲线的影响程度随着含水量的减小而增大。最后,采用Van Genuchten(VG)模型拟合川西混合土土水特征曲线,其拟合参数与颗粒级配、非饱和程度相关,拟合曲线与试验曲线吻合较好。
[Abstract]:The geological structure and climatic conditions in western Sichuan are complex, traffic load and precipitation infiltration often lead to excessive deformation or landslide damage of roadbed of mixed soil in unsaturated state. The engineering properties of unsaturated soil are mainly related to its suction value. In order to understand the influence of mineral composition and initial dry density of unsaturated mixed soil in western Sichuan on the characteristic curves of soil and water, the paper filter method and pressure plate method were used to combine the filter paper method and pressure plate method to shorten the test time for three kinds of sloping mixed soil in western Sichuan mountainous area. The soil and water characteristic curves at different initial dry densities were measured, and the macroscopic phenomena were analyzed by microscopic characteristics, and the influence mechanism of the characteristic factors of mixed soil was explored. The results show that the mineral composition has a significant effect on the soil-water characteristic curve, the higher the hydrophilic mineral content, the greater the matrix suction and the more gentle the curve trend, whereas the lower the matrix suction is when there are more quartz minerals and less clay particles. Under the condition of the same matrix suction, the more dry density, the larger the soil water content, and at the same time, the influence degree of dry density on soil-water characteristic curve increases with the decrease of water content. Finally, the Van Genuchten (VG) model is used to fit the characteristic curve of mixed soil and water in western Sichuan. The fitting parameters are related to particle gradation and unsaturated degree, and the fitting curve is in good agreement with the experimental curve.
【作者单位】： 西南交通大学高速铁路线路工程教育部重点实验室;西南交通大学土木工程学院;
【基金】：国家自然科学基金项目(41572245)
【分类号】：U416.1
本文编号：2277910
[Abstract]:The geological structure and climatic conditions in western Sichuan are complex, traffic load and precipitation infiltration often lead to excessive deformation or landslide damage of roadbed of mixed soil in unsaturated state. The engineering properties of unsaturated soil are mainly related to its suction value. In order to understand the influence of mineral composition and initial dry density of unsaturated mixed soil in western Sichuan on the characteristic curves of soil and water, the paper filter method and pressure plate method were used to combine the filter paper method and pressure plate method to shorten the test time for three kinds of sloping mixed soil in western Sichuan mountainous area. The soil and water characteristic curves at different initial dry densities were measured, and the macroscopic phenomena were analyzed by microscopic characteristics, and the influence mechanism of the characteristic factors of mixed soil was explored. The results show that the mineral composition has a significant effect on the soil-water characteristic curve, the higher the hydrophilic mineral content, the greater the matrix suction and the more gentle the curve trend, whereas the lower the matrix suction is when there are more quartz minerals and less clay particles. Under the condition of the same matrix suction, the more dry density, the larger the soil water content, and at the same time, the influence degree of dry density on soil-water characteristic curve increases with the decrease of water content. Finally, the Van Genuchten (VG) model is used to fit the characteristic curve of mixed soil and water in western Sichuan. The fitting parameters are related to particle gradation and unsaturated degree, and the fitting curve is in good agreement with the experimental curve.
【作者单位】： 西南交通大学高速铁路线路工程教育部重点实验室;西南交通大学土木工程学院;
【基金】：国家自然科学基金项目(41572245)
【分类号】：U416.1
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