The Experimental Study Of The Coefficient Of Experision About Expansive Soil By Restructured Trixial Apparatus

Taking yunnan chenggong strong expansive soil as the research object,using the conventional test method,the intermittent suction method,continuous suction method and the restructuring triaxial apparatus for expansive soil suction expansion stress and the strain measurement,getting the general rule of the stress and strain of soil about the moisture content and the water quantity;The main research results are as follows:1.According to the expansion of the existing theory,through the corresponding simplified,according to the soil of three-phase index of unsaturated soil expansion deformation is deduced general formula δ=ρd/ρωSrΔω+[ρd/-ρωSrω0-(1-ρd/ρs)],and simplifythe expansion deformation of the general calculation formulaδ =α·Δω+ c,and propose the concept of coefficient of expansion.2.By no charge swelling test,intermittent water absorption swelling test and three axis expansion deformation test to measure the expansion deformation,and get expansion deformation and moisture content change of the general linear rule and the changing rule of the coefficient of expansion deformation3.Discussing the relationship between expansion force and suction force,according to the variation of suction in the soil and use poiseuille theory to calculate the amount of expansion stress theoretical formula to get the general formula about expansion stress P = aΔω+ β,and propose the concept of expansion stress coefficient.4..Through balance pressure test,the continuous water absorption expansion force and restructured triaxial apparatus expansion force test,get the similar rule,the size of the expansion force and soil water quantity presents the obvious linear relationship,and prove the feasibility of expansion stress coefficient.5.By modification of the triaxial apparatus of expansive soil stress and strain measurement,through the observation of the relationship between water quantity and the deformation,the water,which into the soil,one part is used in expansion deformation and another part in the form of free water filling into the pore.6.Compared with other test methods use restructuring triaxial apparatus can get a result that the expansion coefficient of stress and strain are changes for the water gradually,it also conforms to the theoretical formula of the coefficient,and is more helpful for the researches on the mechanism of the expansion of the soil.While conventional test method of expansion coefficient,which make the simplified method for calculating the stress and strain,is more conducive to practical application.