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在非饱和黄土压缩特性研究中,需要对天然黄土进行扫描,以获得增湿压缩前黄土微结构形态;对增湿压缩后的土样进行电镜扫描,获得其微结构变化。从微观角度揭示黄土增湿压缩的形成和过程机理,开展控制变量的压缩实验,对实验后的留样开展扫描电镜实验。通过对比黄土在不同含水量、不同压力下受压前后的微观结构变化,分析影响黄土孔隙结构变化的因素,以及孔隙结构在力与水的联合作用下的变化特征及变化过程。得到非饱和土增湿压缩变形的主要因素是外荷超载迫使结构强度的丧失,完成高分维向低分维的转化,改变接触方式,从而由各向同性朝着各向异性发展。
In the study of compression characteristics of unsaturated loess, the natural loess needs to be scanned to obtain the microstructure of the loess before humidification and compression. The microstructural changes of humidified and compressed soil samples are observed under an electron microscope. From the microscopic point of view, the formation and process of loess humidification and compression were revealed, and the compression experiments of control variables were carried out. The scanning electron microscopy (SEM) experiments were performed on the specimens after the experiment. By comparing the microstructure change of loess before and after compression under different water content and different pressures, the factors influencing the change of pore structure of loess and the changing characteristics and changing process of pore structure under the combined action of force and water are analyzed. The main factor to obtain the humidification and compression deformation of unsaturated soils is the loss of structural strength caused by the overload of the external load, the transformation from high-dimensional to low-dimensional, and the change of the contact mode, so that the isotropy develops toward anisotropy.