基于能量演化的反倾层状岩坡多级折断面深度计算模型

Multi-stage fracture depth calculation model of reverse dip rock slope based on energy evolution

多级折断是反倾层状岩质斜坡倾倒过程中普遍发育的一种变形破坏现象。为准确定位反倾层状岩质斜坡倾倒变形过程中多级折断带的埋藏深度,首先从能量守恒角度出发,结合悬臂梁模型,利用外力做功吸收能量与板梁变形释放能量守恒关系推导单层板梁能量平衡方程;在此基础上,根据岩体弹性屈服和弯折破坏2种临界失稳状态,分别推导出2种板梁失稳折断计算模型,并通过改变岩层倾角、斜坡坡角、斜坡高度等参数建立反倾层状岩质斜坡多级折断面深度计算模型;最后,利用离心模型试验和实际工程案例对计算模型的可靠性进行验证。研究结果表明:离心模型试验能够充分揭示反倾层状岩质斜坡倾倒变形过程中存在多级折断现象,整个倾倒变形过程可分为后缘岩体倾倒变形、岩层折断面裂隙逐级形成贯通和斜坡岩体倾倒失稳3个阶段;反倾层状岩坡多级折断面深度计算模型结果与离心模型试验结果、云南某边坡工程案例中各级折断带的埋深相吻合,证明了提出的反倾层状岩坡多级折断面深度计算模型可对离心模型试验和实际工程案例进行较为准确的折断深度定位,且能够根据计算结果判别边坡变形破坏的主要失稳模式。研究成果对反倾层状岩质斜坡的稳定性评价研究及破坏机制分析具有一定的理论和实际意义。

Multiple-stage fracturing is a prevalent deformation failure phenomenon during the tilting process of inclined layered rock slopes.To accurately determine the burial depth of the multi-stage fracturing zones during the tilting deformation process of inclined layered rock slopes,this study analyzed energy conservation principles.Combining a cantilever beam model,it derived an energy balance equation for a single-layered beam by considering the absorption of energy from external forces doing work and the release of energy from beam deformation.Building upon this foundation,the study established two types of unstable fracture calculation models for the beam based on the critical instability states of rock mass elastic yield and bending failure.By altering parameters such as rock layer inclination,slope angle,and slope height,it formulated a multi-stage fracturing depth calculation model for inclined layered rock slopes.Lastly,the reliability of the calculation model was verified through the centrifuge model test and practical engineering cases.Results indicate that the centrifuge model tests effectively reveal the presence of multi-stage fracturing phenomena during the tilting deformation process of inclined layered rock slopes.The entire tilting deformation process can be divided into three stages,which are rear rock mass tilting deformation,gradual formation of fissures on fracture planes,and instability of the slope rock mass.The results of the multi-stage fracturing depth calculation model for inclined rock slopes are consistent with the results of the centrifuge model test and the burial depths of various fracture zones in a slope engineering case in Yunnan Province,China.This demonstrates that the proposed multi-stage fracturing depth calculation model can accurately locate fracturing depths in the centrifuge model test and practical engineering cases,and can identify the main instability mode of slope deformation and failure based on calculation results.The research outcomes hold theoretical and practical significance for stability assessment and failure mechanism analysis of inclined layered rock slopes.