植物根系固土护坡效应的原位测定

通过对南望山山脚下樟树的4个含根土样和素土样在现场进行原位剪切试验,对比素土样和4个含根土样的强度值、位移值,分析评价植物根系的固土护坡效应。结果表明:1)根系的存在提高了土体的峰值强度和残余强度,且根系提高土体残余强度的程度更高;2)同素土样相比,4个含根土样在强度峰值点对应的位移值更大,在土体被剪破前,含根土体能够承受更大的变形,根系增加了土体的延性;3)含根土体的应变软化段曲线较素土体的更加平缓,根系降低了土体峰值点后抗剪强度的减小幅度,使土体在较大应变处仍能保持较高的强度,提高了土体的延性;4)剪切断面上总根长、根面积比与土体抗剪强度的增量均成正相关。

In situ measurement of mechanical effect of plant root systems on soil reinforcement and slope protection

In-situ direct shear tests on the undisturbed soil and four root-soil composite systems of camphors were conducted at the foot of the Nanwang Mountain. Shear strength and displacement of them were compared and mechanical effects of the root systems on soil reinforcement and slope protection were evaluated.The results showed that:1) the shear strength and residual strength of soils were reinforced by root systems and the increased amplitude of the residual strength was higher.2) Compared with the soil without roots,the displacements in the intensity peak of four soils with roots were significant.The latter could withstand greater deformation before cutting break and the root systems increased the ductility of the soil.3) The curves at the strain-softening stage of four soils with roots were more moderate than that of soil without roots.The reducing amplitude of shear strengths of the former after reaching the peak was reduced and the soil with roots could remain a higher strength when a larger strain appeared,so the ductility of the soil with roots was increased.4) The increment of shear strengths was correlated to total root length and root area ratio on the cut section,respectively.