Undisturbed loess analyzed with CT scanning in the process of undrained triaxial compression test(Ⅱ)
LEI Sheng-you~1,TANG Wen-dong~(1,2),WANG Xiao-mou~1, DAI Jing-liang~1(1.School of Highway , Chang'an University,Xi'an 710064,China;2.Architecture Scientific Research Institute of Anhui,Hefei 230001,China)
In order to investigate the micro-mechanism of harden yield damage of undisturbed loess, the authors carried out the un-drained tri-axial compression tests on the undisturbed loess as well as CT scanning the specimen. Combining images and data of the CT scanning with the stress-strain curve, explained the course of harden yield damage by means of damage theory. According to the change of section density deviator stress, and find that at the beginning of shearing, the soil specimen is in elastic state which is undamaged one, and then, the density increases quickly, the structure of the soil begins to reach the stage of destroying. When the axial deformation reaches the value of 12 mm, the density increases slowly, which confirms that the original structure of the soil have been failed and the a new stable one formed. From the curve of CT number-deviator stress, and find that CT number increases with the development of deviator stress greatly, which states clearly that the increase of bearing capacity dependants on the increase of strength of soil, because of the extruding ,the increase of density and section area of specimen contributes to that of strength of the soil , through observing the images of CT scanning ,and find that in the process of shearing ,small pores in the soil become smaller and smaller ,and finally to disappear, big pores are filled with soil grain , so the soil becomes compactness.