An experimental study of the influence of structural parameters on dynamic characteristics of loess. Issue 132 (May 2020) - Wu, Zhijian
Abstract: The structural properties of soil control and influence its macro-mechanical properties. Based on long-term engineering practice, the engineering characteristics and phenomena exhibited by loess in various engineering geological environments are observed to be all related to its structural characteristics. Under different confining pressures and with different water contents, it is found that the structural parameter of loess has a quantitative relationship with macroscopic and mesoscopic parameters. This is based on the triaxial tests of undisturbed loess, saturated loess, and remolded loess with the same dry densities as those of the three typical loess sites in Xiji Ningxia, Ruicheng Shanxi, and Yongdeng Gansu. The test results show that the initial structural parameter decreases with the increase in confining pressure and water content. By processing the meso-image of loess in Xi'ning Qinghai, Yongdeng and Lanzhou Gansu, Xiji Ningxia, and Ruicheng Shanxi with MATLAB and IPP software, and acquiring the corresponding parameters, it is found that there are mesoscopic parameters (porosity, probability entropy, equivalent diameter, and fractal dimension) that are most related to structural parameter. By introducing structural parameter into the dynamic stress-dynamic strain relationship of undisturbed loess, the theoretical and experimental values are observed to be basically consistent, this indicates that the structural dynamic stress-dynamic strain curve can better characterize the deformation and dynamic property of loess under dynamic loading. Highlights: The spatial distribution characteristics of loess meso-structure in the Loess Plateau are presented. The structural parameter of the loess is extracted based on the dynamic triaxial tests. The relationship between the structural parameter, md, and the strain, ε, is obtained. Porosity, probability entropy, equivalent diameter, and fractal dimension are most related to its structural parameter. The structural parameter is introduced into the dynamic stress–strain relationship curve of undisturbed loess.