| Loess is a class of brown soil body, which is widely distributed in northwest China and has large porosity,high strength, special sensitivity to water and collapsibility. the soluble salt is one of the fundamental factors that affect the loess collapsibility and the structural, but the soluble salt in the quantitative study of loess structural impact is little, not enough system and deep. The influence of soluble salt on the structural of the collapsible loess will become the hot topic and difficult point in the study of structural loess. Aiming at the characteristics of ningxia loess and engineering problems.Based on the triaxial test method for soluble salt of TongXin in Ningxia collapsible loess structural quantitative research. First, the TongXin in Ningxia loess, particle composition, soluble salt content, physical and mechanical properties of the loess TongXin in Ningxia are analyzed.Through the four factors three levels orthogonal experiment on the influence of the loess structural,the soluble salt content, dry density and water content, as factors were discussed. Among them, the author puts forward the concept of structural similarity coefficient and structural similarity coefficient evaluation and control structural similarity of the remoulded sample and undisturbed soil samples, and study of structural loess from the angle of the soluble salt content are unique in this article. The results show that the loess structural increases along with the increase of dry density, salinity, decreases with the increase of moisture content. No matter what moisture content is high or low, soluble salt is one of the important factors that affect the loess structural. Then basing on in the orthogonal experiment results, the single factor of soluble salt experiment is processed, the relation of different kinds of soluble salt and loess structural is analyzed. The soluble salt in0.6-1.8%, the approximate linear relationship between salinity and structural parameters is found and the loess structural impact is biggest. Structure strength of the specimen and the salt content has a quadratic curve relationship and structural parameters and the salt content is three times, the correlation coefficient R2is close to1.O.They have good correlation. The loess structural influence degree of different salts are different.The order of effection is CaCl2<Na2SO4<composite salt (CaCl2:Na2SO4=3:7).that Soluble salt exists in crystalline state the influence of on structural loess is higher than the ionic state. There is important theoretical significance to enrich and develop the loess structural theory, and to further reveal the mechanism of loess collapsibility. |
