根系作用下的基材土–岩接触面原位剪切试验研究

采用自制原位剪切仪,对不同粗糙度、不同多花木蓝根系密度的基材土–岩接触面进行原位剪切试验,研究了基材土–岩接触面的剪切变形特征。研究表明,基材土–岩接触面剪切应力–位移具有典型的软化特性;受根系加筋、锚固作用影响,含根试样的剪切破坏面粗糙、破碎。根系作用对土–岩接触面峰值剪切强度、峰值剪切位移及残余剪切强度影响明显,对比发现,不同粗糙度下,相同根系面积比对提高界面峰值剪切强度的贡献率差异较小;根系面积比较小时,增强界面峰值剪切强度的贡献率低于粗糙度,随着根系面积比增大,根系提高界面强度的作用更为明显,其贡献率显著增加。

In-situ shear tests on base material soil-rock interface interacted by roots

The shear characteristics of base material soil-rock interface are studied by means of in-situ shear tests by using the homemade shear apparatus under various interfacial roughnesses and root densities of Indigofera amblyantha. The test results reveal that the shear stress-displacement of the base material soil-rock interface is characterized by typical shear softening. Under the reinforced effect of roots on base material soil and its anchorage effect on soil-rock interface in the tests, the rooted samples exhibit rough fractured shear failure plane. The contribution of roots to improving the interfacial peak shear strength, peak shear displacement and residual shear strength is significant. According to the comparison, it is found that the contribution differences are small for the same root area ratio (RAR) to improving the intrfacial peak shear strength under different roughnesses. For a small RAR, the contribution ratio of roots is lower than that of interfacial roughness. As RAR increases, however, the effect of roots on improving the interfacial peak shear strength is more obvious, the contribution ratio of roots thus increases significantly.