The residual strength of sliding basal soils plays a pivotal role not only in the movement of bedding landslides controlled by clay-rich interlayers but also in remobilized granular deposits. Many studies have focused on better understanding the residual shear behaviors of clayey and granular soils under relatively low shear rates. However, the residual strength varies with various clay fractions for clayey soils and fine-size fractions for granular soils, as well as shear rates (especially in fast ranges) need further examined. In the present research, results of a low- to high-rate continuous ring shear test on a clayey soil and three granular soils at the shear rates ranging from 0.5 to 50.0 mm/s were reported. The clayey soil was remolded from the shear zone soil of a bedding landslide controlled by a clay-rich interlayer with main minerals of illite-smectite, and the granular soils included two silica sands and one mixture of silica sand with fine granite residual soil particles. The results show that saturated clayey soil has an obvious positive shear rate effect on its residual strength after a certain shear rate; the mechanism is the transformation of shear mode, i.e., from sliding shearing to turbulent shearing with the increasing of shear rate. The high clay fraction may promote this transformation of shear mode. In addition, the critical shear rate of the clayey soil that has a positive shear rate dependency of the residual strength (i.e., rate-strengthening) is related to the clay fraction, i.e., a smaller critical shear rate appears in the clayey soil with higher clay fraction. The residual strength of saturated granular soils with different fine-size fractions do not show any shear rate-dependent, while the fine-size fraction affects the residual strength both in drained and undrained conditions; that is, the higher the fine-size fraction is, the lower the residual strength is. Moreover, the neutral shear rate effect of granular soils in this study may be related to the low normal stress and low shear rate range. The authors believe that, results such as those obtained in this work, may be useful for developing a more suitable constitutive model to better understand the postfailure motion (or reactivation kinematics) of bedding landslides controlled by clay-rich interlayers, as well as rock avalanche deposits remobilized by heavy rainfall.

滑动基层土的残余强度不仅在受富含粘土夹层控制的层理滑坡运动中起关键作用，而且在再活化的颗粒沉积物中也起关键作用。许多研究都集中在更好地了解粘土和粒状土壤在相对较低的剪切速率下的残余剪切行为。然而，剩余强度随粘土的各种粘土分数和粒状土壤的细粒度分数而变化，以及剪切速率（特别是在快速范围内）需要进一步检查。在本研究中，报告了在剪切速率范围为 0.5 至 50.0 mm/s 的粘土和三种粒状土壤上进行的低速至高速连续环剪切试验的结果。黏性土由以伊利石-蒙脱石为主要矿物的富粘土夹层控制的顺理滑坡剪切带土改造而成，颗粒土包括两种硅砂和一种硅砂与细花岗岩残余土颗粒的混合物。结果表明，饱和黏性土在一定剪切速率后对其剩余强度有明显的正剪切速率影响；其机理是剪切方式的转变，即随着剪切速率的增加由滑动剪切转变为湍流剪切。高粘土比例可能会促进这种剪切模式的转变。此外，剩余强度与剪切速率呈正相关（即速率强化）的粘土临界剪切速率与粘土分数有关，即 粘土含量较高的粘土中出现较小的临界剪切速率。不同细粒级饱和颗粒土的残余强度不表现出任何剪切速率依赖性，而细粒级影响排水和不排水条件下的残余强度；即细粒率越高，残余强度越低。此外，本研究中粒状土的中性剪切速率效应可能与低正应力和低剪切速率范围有关。作者认为，在这项工作中获得的结果可能有助于开发更合适的本构模型，以更好地理解富含粘土夹层控制的层理滑坡的破坏后运动（或重新激活运动学），