Study On Coarse-grained Material Wetting Deformation Characteristics On Scale Effect

The wetting deformation of coarse-grained soil is a key problem in design of high earth rockill dam, but it is not solved well so far. And the difference caused by the scale effect is difficult to grasp in the experiment of coarse grained soil. In this thesis the wetting deformation and the scale effect of coarse-grained soil are studied systematically and intensively by wetting deformation test, analysis of test results.In this thesis the design gradation of Shuangjiangkou rockfill dam main rockfill is taken as the prototype and it is scaled by using equivalent substitution method、mixing method、elimination method、similar grading method. The scale test materials of dry and saturated state with 20mm and 10mm as the biggest grain size of each substitution grading are studied by using the three axle shear test instrument. Through the three axis test influence law of scale effect on strength and deformation of coarse grained soil is revealed; the reasons for the decrease of the strength and the increase of the volume of the test grade materials after saturation are discussed; the relationship on wetting axial strain, volume change and slaking stress levels of the test grade materials got from different scaling methods is explored.Three axis shear test of two kinds of coarse grained soil, limestone and basalt is conducted with dry and saturated states. According to the test results, the influence of the characteristics of the parent rock and the shape of particles on the strength and deformation of coarse grained soil is analyzed.By sorting the results of the single point test, it is found that the rule of particle breakage on the test grade materials got from different scaling methods is different under the same conditions;the relationship between particle breakage and soil strength is obtained and it is found that the coarse grained soil secant angle of internal friction and particle breakage rate is a power function by fitting.