ANALYSIS OF HUMIDIFYING DEFORMATION CHARACTERISTICS AND MICROSTRUCTURE OF LOESS IN XINING AREA

This paper aims to examine the collapsible loess in Xining area. The burial depth and humidifying water content are analyzed with the confined compression tests for the change regularity in the collapsible deformation and compressive deformation of loess under humidifying conditions. Qualitative analysis is carried out on the microstructure of different humidification loess samples by means of scanning electron microscopy. Macro-microscopic analysis is further carried out for the relationship between the microstructure of the loess sample and the collapse deformation. The results show the follows. (1)With the increase of water content, the amount of collapse deformation and compression under the same pressure gradually become smaller. The soil will be compressed, the strength will be increased, the compressibility will be weakened, and the collapsibility will be weakened or there will be no collapsibility when the water content increases to a certain extent. (2)Due to the influence of loess stress history on its structure and collapsibility, with the increase of burial depth and water content, the 5m loess exhibits less humidification and deformation and compressive deformation than the 3m loess. (3)With the increase of water content before and after immersion, the arrangement of pores tends to be stable, the particle distribution is gradually concentrated. The degree of agglomeration becomes higher, the proportion of pore area gradually decreases, the pore morphology gradually becomes narrow and the macroscopic humidifying deformation of loess before and after water immersion consistent performance.