滑带涉水劣化及古滑坡复活研究

The slide strength degradation is one of the most important facts that can induce landslide disaster of reservoir, which is under state of reservoir filling. So it is meaningful to study the ancient landslide resurgence mechanism induced by slide strength degradation. Based on rock mass of wade slide band being under saturated and unsaturated circulation state, this study combines research techniques of geological survey, laboratory experiment, theoretical analysis and numerical modeling to studies and evaluates the slide band from the angle of basic physical and mechanical properties; and then study the strength attenuation, structure degradation and material composition change rule by the research technique combined macrocosmic and microcosmic aspect, and the calculation model of slide band strength degradation is established. In the end, the seepage characteristics of reservoir bank landslide are studied by combining theoretical analysis and model test, to reveal the resurrection mechanism of reservoir bank landslide which is induced by rock mass strength degradation that caused by fluctuation of water table. The study results are meaningful to the environmental protection and safety of reservoir area, and also can be used to provide scientific basis for prediction of the reservoir bank slide instability.

滑带强度劣化是水库蓄水诱发滑坡灾害的最重要因素之一。研究库水作用下滑带劣化诱发古滑坡复活机理具有重要的意义。本项目针对涉水滑坡滑带岩土体处于饱和、非饱和循环状态下的特点，综合采用现场地质调查、室内实验、理论分析、数值模拟相结合的研究手段，首先从基本物理力学性质对滑带进行研究，综合评价滑带土的物理力学特性；然后采用宏微观相结合的手段研究滑带在干湿循环作用下的强度衰减、结构劣化及物质成分的变化规律，从微观角度阐述滑带强度劣化的内在原因，建立滑带强度衰减的计算模型。最终，结合理论分析及模型试验研究库岸滑坡的渗流场特征，揭示水位变动带岩土体强度劣化的库岸滑坡体复活机理。研究成果可为具有典型地质特征的库岸边坡失稳的预测预报提供科学依据，同时对水库诱发滑坡的防灾减灾、库区环境保护具有重要意义。

滑带（岩）土体强度涉水劣化是水位周期性变动下库岸古老滑坡复活失稳研究中的关键科学问题之一。本项目选取三峡库区黄土坡滑坡为研究对象，开展了库水涨落引起的干湿循环下消落带滑带土劣化机理研究。通过现场取样、力学试验、微观结构测试、物性测试等技术手段，揭示了滑带土在干湿循环作用下的强度衰减、结构劣化及物质成分的变化规律。利用直剪试验联合滤纸法测量基质吸力的方法，获取了干湿循环过程中滑带土抗剪强度随基质吸力的演化规律，建立了全吸力范围内的非饱和抗剪强度拟合模型；利用核磁共振测试技术获取滑带土微观孔隙分布特征，结合孔隙分形理论，建立了微观结构参数与土-水特征曲线间的定量关系；由此，构建了干湿循环作用下滑带土微观结构演变与宏观强度变化的定量表征，揭示了干湿循环下滑带土劣化机理。在此基础上，利用数值模拟，研究库岸滑坡的渗流场特征，揭示水位变动带岩土体强度劣化的库岸滑坡体复活机理。研究成果可为库岸滑坡变形演化、稳定性评价、失稳预测提供科学依据，同时对水库诱发滑坡的防灾减灾、库区环境保护具有重要意义。

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