Research progress on collapsible characteristics of loess and its modification methods
In order to reduce the hazards of a series of geological disasters caused by loess collapsibility,the research results of loess collapsibility at the present stage were sorted out and analyzed,some of the important results obtained by the three mainstream research methods in the microscopic study of loess collapsibility were summarized,the evaluation methods of loess collapsibility at home and abroad and their focus on the differences were analyzed,the modification methods of collapsible loess were summarized and the prospect of the future research of the microscopic mechanisms of loess collapse and the evaluation of collapsibility was provided.The results show that the root cause of the collapsibility of loess is its own unique bracket structure,when loess is exposed to water,some of the clay particles in the bracket structure undergo hydration and expansion,leading to particle slippage,and as the water content reaches the threshold,the weak connections in the loess structure will be the first to be damaged so the stability of the bracket structure is significantly affected by the water content.At present,based on the multiple linear regression method,the partial least squares method,and other methods,a lot of collapsibility evaluation theories have been established on the relationship between loess collapsibility and various physical indexes,soil layer depth,and microstructure parameters.Aiming at the difference between the calculated value and measured value of loess collapsibility,scholars propose correction coefficients,discontinuous distribution effect coefficients of collapsible loess,and other parameters for correction.The modification methods of collapsible loess can be divided into two categories:physical modification and chemical modification.Physical modification methods such as the water immersion method and the deep ramming method realize modification by changing the pore structure and particle arrangement of the soil.The various kinds of curing agents added in chemical modification reinforcement will have a series of reactions with water and soluble salts in loess,increasing the content of clay particles and cement in loess and thus realizing the improvement of various properties of loess.
loesscollapsibilitymicroscopic mechanism of collapsecollapsibility evaluationmodification
万方数据
维普
