Anisotropy of macro and micro characteristics of remolded Nanning expansive soil
In order to reveal the influence of expansive soil meso structure on the macro expansion,Nanning re-molded expansive soil was studied.The macro test is carried out by self-developed three-dimensional dilatometer to obtain the influence law of dry density on expansion rate.The meso pore and soil particle structure are studied through CT scanning test.The meso characteristics and fractal characteristics of pores and particles are systemati-cally analyzed based on Avizo software.Combined with three-dimensional macro test,the influence of meso struc-ture characteristics on macro expansion deformation is revealed.The results show that the horizontal expansion rates of the sample are basically the same.The vertical expansion rate is greater than the horizontal expansion rate.With the increase of dry density,the ratio of horizontal-vertical expansion rate is close to 1.The ratio of ver-tical-horizontal porosity increases with the increase of dry density;When the ratio of horizontal-vertical expansion is close to 1,the ratio of vertical-horizontal porosity is larger,indicating that there is a good relationship between horizontal-vertical porosity and macro horizontal-vertical expansion.The ratio of vertical-horizontal soil particle size decreases with the increase of dry density.When the ratio of horizontal-vertical expansion rate is close to 1,the ratio of vertical-horizontal soil particle size is smaller,indicating that there is also a good relationship between horizontal-vertical soil particle size and three-dimensional expansion rate pore fractal dimension is used to charac-terize pore complexity,which is not directly related to three-dimensional expansion rate.