The Residual Shear Properties Of Three Kinds Of Plant Single Root To Improve Soil

This paper applies soil mechanical theory and experimental method, through increasing remoulded soil displacement to do direct shear test in the lab, sdudied these plants which were Caragana microphylla Lam.、Artemisia sphaerocephala Krasch. Hippophae rhamnidsLinn. root-soil composite and every influence factors residual strength characteristics, the results as following:When three kinds of plants root-soil composite shear displacement exceeded the soil test specification and the shear displacement was more than14mm, three kinds of plants root-soil composite has a larger ability to resist deformation than prime soil.During fast shear conditions, in the same diameter range the residual strength of these three plants root-soil composite all exceed pure soil; the residual cohesion: Caragana microphylla Lam.(36.76%)＞Artemisia sphaerocephala Krasch.(16.95%)>Hippophae rhamnides Linn.(10.10%) the residual internal friction angle has no obvious change.During slow shear conditions, the residual strength of these three plants the representative root-soil composite compare with pure soil was Artemisia sphaerocephala Krasch.＞Hippophae rhamnides Linn.＞Caragana microphylla Lam.; the residual internal friction angle has no obvious change.With the increase of soil moisture content, the residual strength and cohesion of these three plants root-soil composite has a trend of the first increase then in lower, the residual internal friction angle has a trend of the decrease. With the increase of soil density, The residual strength and cohesion of these three plants root-soil composite has a trend of the increase, the residual internal friction angle has no obvious change. With the increase of root diameter,the residual strength and cohesion of these three plants root-soil composite has a trend of the increase, the residual internal friction angle has no obvious change.The residual strength and the residual cohesion of these three plants the representative root-soil composite in different directions:the reverse root distribution>the vertical root distribution＞the lateral root distribution＞the forward root distribution, the residual internal friction angle of the reverse root distribution and the vertical root distribution has no obvious difference,but it was more than other distributions. With the increase of the number of the roots, the residual strength and the residual cohesion of these three plants the representative root-soil composite all has a trend of the increase; the residual internal friction angle has different trends.