Influence Of Moulding Water Content On The Soil Water Characteristics And Deformation As Well As Strength For Compacted Loess In Lanzou

Loess is a kind of special soil.During the compaction process,it is often used to press the soil of the optimum moisture content to the same degree,after a rainfall and evaporation,soil compaction is ultimately have the same dry density and experimental water content,but internal macro structure of soil is different,resulting in different engineering properties of soil.So the research of influence of moulding water content on deformation characteristics of compacted loess,to solve the problems of engineering for compacted loess is very meaningful.Take the compacted loess samples of Lanzou for the same dry density(a certain degree of compaction)but different moulding water content(near the optimum moisture content),wet increase or decrease to the same experimental water content to experiment,so as to take a series of research on deformation and strength and soil water characteristics of compacted loess.This essay first through a series of unconfined compression tests under different conditions,analysis the influence of different structures caused by the change of molding water content on the stress-strain and strength characteristics as well as the structural parameter was investigated for the compacted loess with different experimental water contents.The initial structural parameters can well reflect the influence together with molding water content and experimental water content on compacted loess structure.There is a good normalization between the unconfined compression strength and the initial structural parameters under different molding water content,which is in line with the linear function relationship.Through a series of compression tests with controlled suction and wetting tests in stage under the condition of lateral confinement,the influence of structure caused by different molding water contents on the compressive properties and collapsible deformation as well as soil water characteristics was analyzed for compacted loess with different initial testing water contents and the path of force water.The structure yield pressure and the initial structural parameters are well normalized and can be described with a hyperbola.The ratio of pore ratio and compressive stress ratio in different conditions are well normalized.Through the triaxial consolidation drained shear tests under different conditions,analysis the influence of confining pressure and molding water content as well as experimental water contents on deformation strength characteristic and yield characteristics for the compacted loess with different experimental water contents.The strength index and the initial structural parameters have a good normalization,which corresponds to the power function relation.The yield line under different conditions on the q-p plane approximates the oblique ellipse of the symmetric and k0 lines.Through the plane strain triaxial shear test under different confining pressures of compacted loess with different water content in Lanzhou,the law of development of the principal stress in the plane strain direction is studied,and the characteristics of the middle principal stress are revealed and described.such as the analysis of plane strain and two kinds of conventional triaxial stress state of stress and strain,the relationship between the strain,intensity,etc,is given based on the rule of Lade-Duncan of the relation between the two kinds of stress intensity index.