顺层岩质滑坡宏观变形—启滑过程的能量学解析

Bedding rockslide generally develops in some consequent slopes with an interbed or sandwich structure of hard and soft rocks. It has a process from progressive deformation to sudden failure, which is caused by its internal structure. System theory indicates that ground deformation is the function presentation of physical structure change, and the soft structure change, i.e. stress and energy, determines the failure mode of rockslide. Study of ground deformation mechanism and energy analysis of bedding rockslide is proposed to guide landslide prediction. Based on the geological model of bedding rockslide, an energy analysis model of bedding rockslide composing of hard and soft rocks was proposed to explain its development from deformation to failure by considering balances of force and energy with slide face progressive damage. And, ground deformation mechanism of bedding rockslide was studied by survey representative bedding rockslides, physical experiment and FLAC3D simulation. Then, mechanics experiments of rock and similar material of hard and soft rock combination was conducted for acquiring mechanics and energy parameters of rock. And, PFC was employed to simulate force and deformation of rock block, layer rock mass and rockslide. The simulation result was used to determinate the key parameters and verify reliability of energy analysis model. Finally, the criterion of ground deformation to determine landslide development stage is proposed by applying ground deformation mechanism. Also, the starting velocity and acceleration of landslide is forecasted according to the energy release of rock mass while landslide begins failing. The research has important scientific significance on developing of landslide dynamic theory, improving of the landslide prediction model.

岩质滑坡常发育在软硬互层或夹层的顺向斜坡内，其演化是内部结构由渐变到突变的过程。滑坡宏观变形是硬结构变化的功能表现，而力和能量的软结构变化决定着滑坡的启动模式。为探究滑坡内部结构演化机理，拟开展顺层岩质滑坡启滑前宏观变形机理和能量学解析研究。在滑坡地质模型研究基础上，构建软、硬岩组合顺层岩质滑坡变形—启滑的能量学解析模型，通过力和能量平衡解释软弱滑动面损伤(或软化)引起的滑坡演化。对秭归沙镇溪镇青干河和锣鼓洞河左岸典型滑坡开展调研，结合室内物理模型实验和FLAC3D数值模拟，揭示滑坡地表宏观变形破坏的内在机理。基于岩石、软硬岩组合相似材料的力学实验，利用PFC 模拟岩块、层状岩体和滑坡三个尺度的变形破坏，确定解析模型中力学和能量学的关键参数，并验证模型的可靠性。从而，建立滑坡不同演化阶段的宏观变形判据，预测滑坡启动速度。成果对发展滑坡动力学理论、完善滑坡预测预报模型具有重要的科学意义。

岩质滑坡常发育在软硬互层或夹层的顺向斜坡内，内部结构存在渐变到突变的演化过程。为了科学地指导滑坡预测预报，项目围绕顺层岩质滑坡启动前宏观变形机理和能量学分析开展研究。在秭归、巴东和万州等地顺层岩质滑坡调研基础上，围绕3类常见顺层岩质滑坡和3套易滑地层开展研究。. 通过循环加载实验提高了岩样测试效率，提出了适合于少量岩样的脆性和损伤分析方法；建立了岩石细观-宏观结构参数测试分析方法，研究了岩石力学过程结构参数的演变规律和敏感性。结合Hoek-Brown强度准则，建立了存在贯通和非贯通节理岩体能量参数的估算方法，对比PFC3D模拟结果验证了方法的合理性。. 考虑滑体和滑动面协同变形、滑坡力和能量平衡，建立了顺层岩质滑坡渐进破坏过程变形-力-能量的解析模型，提出了加速变形-临滑的判据。考虑了地貌演化和环境因素组合，以作图法和解析法对3类滑坡进行求解，分析了滑坡在后缘竖向裂隙，前缘顺层或切层剪出情况的演化特点，总结了滑坡宏观变形规律和加速变形-破坏判据。针对侏罗系红层崩滑体演化，推导了降雨沿竖向裂隙的水压力，建立了岩石崩滑体三维稳定性分析模型。. 围绕流域滑坡易发性评价无法考虑地质地貌演化的问题，提出了混合单元法求解斜坡侵蚀强度及流域滑坡易发区的新方法，以侧蚀和下蚀的比例系数划分河谷演化阶段，分析河段演化模式，并将河谷地貌演化用于滑坡易发性评价。该模型能够定量评判流域老滑坡的成因和新生滑坡的易发性。. 项目成果提出了从岩石、岩体到顺层岩质滑坡的力学和能量学解析模型，获得了三峡库区最常见3类顺层岩质滑坡渐进破坏的演化规律和判据，将混合单元法用于香溪河河段地质地貌演化和滑坡易发性分析，对发展滑坡动力学理论、完善滑坡预测预报模型具有重要的科学意义。