滑带土残余强度的速率效应及其对滑坡变形行为的影响

Rate effect of residual strength of slip soils and its impact on deformation process of landslides

选取三角滩滑坡滑带土进行环剪试验,分析滑带土残余强度的速率效应及含水率对速率效应的作用,结合数值模拟揭示速率效应对滑坡变形行为的影响。研究结果表明:三角滩滑坡滑带土残余强度具正速率效应;滑带土残余强度的速率效应可表示为φ_r=Aln(v)+B,其中速率效应系数A反映速率效应的类型与剧烈程度;正速率效应下,受土体自身黏滞性与细颗粒定向性的交互影响,A随着含水率的增加先减小后增大;受正速率效应的影响,滑带土残余强度的动态变化控制着滑坡由活动阶段过渡到稳定阶段,揭示滑带土残余强度的正速率效应对滑坡的变形行为具有重要的影响,为滑坡"走走停停"的变形特性提供解释。

Using ring-shear testing on reconstituted soil samples from the Sanjiaotan landslide over a wide shearing rate,the impact of shearing rates on the residual strength of slip soils and the influence of moisture content on the rate effect were studied.The relationship between the rate effect and the deformation process of landslide is explored by the numerical simulation technology.The results show that the residual strength of samples is positively dependent on the shearing rates.The equation which quantitatively assesses three types of rate effects is presented:φr=Aln(v)+B,in which A is the rate effect coefficient.The residual strength of slip soils can display different types and violent degree of rate effects,accompanying A.Due to the viscosity of soils and the alignment of clay particles,the value of A increases firstly,and then decreases with the increment of moisture content in the positive rate effect.Affected by the positive rate effect,the residual strength of slip soils presents a dynamic change.It determines the process from active stage to stable stage of landslides.In summary,the rate effect on residual strength of slip soils plays a decisive role in the deformation process.