Experimental Study On Dispersive Factors Of Cohesive Soils

Dispersive clay is eroded easily by flowing water, so it is easy to cause great destructionfor some water conservancy and hydropower construction projects. Dispersive clay are widelyspread in China. The research of dispersion mechanism of cohesive soil and its affectingfactors has some practical significance.The study basing on the double electric layer theory, and the force between soil particles,the knowledge of soil mechanics, agrology, soil electrical, soil physics, soil chemistry, using avariety physical and chemical properties data of soil and dispersive property to studydeterminant of dispersive property of clay and dispersive mechanism of clay by internal andexternal factors. Provide applications of the dispersion of clay for the engineering intheoretical basis.First of all, study on the mechanism of dispersive soils in the internal aspect. Comparingthe physical and chemical properties, mineral composition with the results of the dispersiveproperty of the clay, study the relationship between the limits of moisture content, claycontent, cement, mineral type and the dispersion mechanism of clay.Second, study on the mechanism of dispersive soils in the external aspect. ComparingpH, cation content and its concentration with the results of the dispersive property of the clay,study the relationship between the limits of moisture content, clay content, cement, mineraltype and the dispersion mechanism of clay.Combined the results of the dispersive property of the clay by fragments test and doublehydrometer test,study how pH and cation content, and its concentration in medium to effectthe results of the dispersive property of the clay.The key conclusions in this thesis can be summarized as follows:1. The dispersive mechanisms of clay has relationship with Clay liquid limit, plastic limit,clay minerals, Montmorillonite conten and Illite content, and clay content, cementcontent,but not the major determining factor.2. The dispersive mechanisms of clay has large relationship with PH value, cation type,cation concentration, and cation price in the surrounding environment.3. The study result that a certain content of Na+and a certain alkaline pH value arenecessary conditions to make clay dispersive. 4. When the soil is dispersive,high-priced cation in the surrounding environment takesthe replacement of Na+in the soil particles easily,and restrains the dispersion of the soil moreobviously and efficiently.