毛乌素沙漠南缘粉细砂湿陷特性试验及影响因素研究

Experimental study on collapsibility characteristics of silty fine sand in the southern edge of Mu Us Desert and its influencing factors

毛乌素沙漠地区部分粉细砂表现出遇水强度降低、竖向变形沉降增大的特性,研究该地区粉细砂湿陷特性及其影响因素是该地区工程建设中亟待解决的问题之一。本文以毛乌素沙漠南缘粉细砂为研究对象,通过一系列室内特性试验,研究在不同垂直压力、试样干密度、初始含水率和粒径级配下粉细砂的湿陷特性及其影响变化规律。结果表明:砂土试样的湿陷性随试验压力的增大呈现先增大后减小的趋势,随试样干密度的增大而减小,随初始含水率的增大而减小,随粒径的增大而减小;通过单因素分析法,结合各因素对粉细砂湿陷系数影响幅值的大小,可以得出干密度是影响砂土湿陷性的主要因素,初始含水率、粒径大小和垂直压力是影响砂土湿陷性的次要因素。该研究结果可为毛乌素沙漠地区工程建设提供参考,为同类型场地湿陷性研究提供借鉴。

Some silty fine sands in Mu Us Desert show the characteristics of the reduced strength when encountering water and the increased vertical deformation and settlement.To study the collapsibility characteristics of silty fine sands in the area and its influencing factors is one of the problems to be solved urgently in engineering construction in the area.In this paper,the silty fine sand in the southern edge of Mu Us Desert is taken as the study object,and a series of indoor characteristic tests are conducted to study the collapsibility characteristics of silty fine sand under different vertical pressures,sample dry density,initial moisture content and particle size grading,as well as its influence on the change law.The study results show that the collapsibility of sand samples shows a trend of first increasing and then decreasing with the increase of test pressure,decreasing with the increase of sample dry density,decreasing with the increase of initial moisture content,and decreasing with the increase of particle size;through the single factor analysis method,combined with the magnitude of the influence of various factors on the collapsibility coefficient of the fine sand,it can be concluded that the dry density is the main factor to affect the collapsibility of the sand,while the initial moisture content,particle size,and vertical pressure are secondary factors to affect the collapsibility.The study results could provide the reference for engineering construction in Mu Us Desert area and for collapsibility study of similar sites.