黄土边坡的地质结构界面效应及其促滑机制研究

The sliding catastrophe of loess slopes on the loess plateau occurs frequently in recent years，which threatens the major project construction and the safety of people's lives in western region. The geological structure interface effect on sliding catastrophe of loess slopes is prominent and the disturbance of external hydrodynamic condition is conspicuous. All these lead the sliding catastrophe of loess slopes to be very concealing, destructive, difficult to be predicted. In this case, could the traditional analytical theory and models accurately apply to the stability studies for loess slopes with geological structure in? Therefore, the field geological investigation, field monitoring, laboratory test and numerical simulation analysis would be conducted to explore the mesoscopic pregnant mechanism of loess catastrophe and the macroscopic sliding mechanism of loess slopes based on the geological interface structure effect in loess slopes. Then the strength destruction law of loess in mesoscopic scale and the characteristics of time-dependent loess slope deformation in macroscopic scale will be found out to solve the pregnant catastrophe effect of geological structure interface. The catastrophe regulation of loess slopes caused by the interplay of geological structure and hydrodynamic condition will be found out to solve the catastrophe -caused effect of the geological structure interface. This research will provide theoretical and technical supports for the stability study of loess slopes in western region, by which there would be certain scientific significance and practical value.

近年来黄土高原地区黄土边坡滑移灾变频发，对西部地区重大工程建设与人居安全构成威胁。黄土边坡“地质结构界面效应”突出、外部水动力条件影响显著，造成黄土边坡滑移灾变隐蔽性强、破坏性大、预测困难。传统分析理论与模型还能否精准适用于考虑“地质结构界面效应”的黄土边坡稳定性研究？值得进一步的学术探索。因此针对黄土边坡的“地质结构界面效应”问题，综合利用野外地质调查、现场监测、室内试验、数值模拟等手段探索考虑“地质结构界面效应”的黄土体细观孕灾机制、黄土边坡宏观滑移机制。查明考虑“界面效应”的黄土细观小尺度强度破坏规律、黄土边坡宏观大尺度时效变形特征，解决地质结构界面的孕灾效应问题；查明黄土边坡地质结构界面与水动力条件互馈对黄土边坡的致灾规律，解决地质结构界面的致灾效应问题。研究成果可为西部地区黄土边坡稳定性研究提供理论与技术支撑，具有一定的科学意义及实用价值。

黄土边坡“地质结构界面效应”突出、外部水动力条件影响显著，造成黄土边坡易滑移失稳。为此，综合利用野外地质调查、现场监测、室内试验、模型试验等手段开展黄土边坡的地质结构界面效应及其促滑机制研究。查明了考虑“界面效应”的黄土细观小尺度强度衰减规律、黄土边坡宏观大尺度时效变形规律，解决了地质结构界面的孕灾效应问题；查明了黄土边坡地质结构界面与水动力条件互馈对黄土边坡的致滑效应，解决了地质结构界面的促滑机制问题。具体研究成果如下：从细观小尺度层面阐明了结构界面（节理界面、接触层面）对黄土界面强度与变形特性影响，揭示了考虑“界面效应”的黄土强度衰减规律及其影响因素，建立了考虑“界面效应”的黄土剪切强度模型公式；从野外长时序角度查明了结构界面（接触层面、挖填界面）对黄土边坡时效变形影响规律，揭示了结构界面对黄土边坡差异变形影响机制；从宏观大尺度角度查明了结构界面（接触层面、挖填界面）对黄土边坡滑移破坏过程影响，揭示了结构界面对黄土边坡滑移的促滑机制。从而解决了考虑界面效应的黄土边坡滑移灾变孕育机制、触发成灾机制等关键问题，为黄土长期边坡稳定性研究提供重要理论与技术支撑。