基于流变模型的反倾层状岩体倾倒变形发育深度的力学分析

Geological Model Analysis on the Depth of Toppling Deformation in the Anti-dip Rock Slopes

为了研究反倾层状岩体倾倒变形的发育深度,结合倾倒变形发展演化过程的时效性特点,将岩层抽象为在自重及层间应力作用下的弯曲悬臂梁,选取Kelvin流变模型,以变形发育极限位置处拉应变为零作为发育深度的判据,计算得出了层状岩体倾倒变形的发育深度;并利用发育深度恒为正的特点得到了倾倒变形发生的判据条件。计算结果表明,层状岩体倾倒变形发育深度受岩性条件及坡体结构的影响;而倾倒变形发生与否则主要受到岩层倾角、边坡坡角及层间内摩擦角的影响。结论可以为倾倒变形边坡变形规模判断及稳定性分析提供依据。

The study focuses on the depth of toppling deformation occurred in the anti-dip rock slopes with the consideration of the time-sensitive characteristics of the development process. The proposed rheological model is modified on the basis of the Kelvin model,which consider the rock layers as curved cantilevers that are subject to self-weight and inter-layer stresses. The mode estimates the depth of the bended rock layers by using the fixed column base as the zero deformation point,of which the results facilitate the determination of the possibility of toppling failure. The proposed model revealed that the depth of the toppling failure is governed primarily by the lithological condition and localized geological setting of the slope,whereas the possibility of toppling failure largely depends on the strata inclination,slope angle,and interlayer internal friction angle. The study aids to the understanding on the magnitude of toppling deformation and slope stability analysis.