极端动态渗透压下含碎石滑带土的粘滑蠕变演化机理研究

Effect of stick-slip creep properties of slip zones’ soil with gravel on the deformation prediction of reservoir landslide under the extreme changes in water level is necessary to be studied. The evolution mechanisms of nonlinear stick-slip creep of gravel-rich sliding soil need to be explored under extreme dynamic osmotic pressure. With the research object of deep gravel-rich sliding soil of Huangtupo landslide, based on the characteristics of stick-slip creep in the time dependence plot, the self-designed creep equipment will be used to carry out large-scale creep tests of gravel-rich sliding soils under drastic dynamic osmotic pressure to establish the quantitative method of stick-slip creep parameters. Combined with CT scanning technique, the mesoscopic components and structures are obtained with non-destructive and dynamic methods. Based on the real trajectory and time dependence curve of gravel, the criterion model of stick-slip creep will be proposed considering gravel and stick-slip rate and the dynamic associated characteristics of gravel properties and stick-slip creep will be studied. Based on near 10-years extreme dynamic changes data of reservoir water level, the stick-slip creep tests will be carried out. The stick-slip creep model of “stable seepage-extreme dynamic seepage-gravel characters” will be built so as to reveal the evolution mechanism of nonlinear stick-slip creep of gravel-rich sliding soil under extreme dynamic osmotic pressure. Finally, the corrective method of time dependence deformation of reservoir landslide is proposed considering stick-slip creep. The research of evolution mechanism of stick-slip creep of gravel-rich sliding soil will promote the development of Yangtze river economic zones and provide the theoretical basis for the prediction and forecasting and warning of reservoir landslide.

库水位剧变下深层含碎石滑带土的“粘-滑”蠕变特性影响水库滑坡时效变形精确预测，急需探索极端动态渗透压下含碎石滑带土的非线性粘滑蠕变演化机理。以黄土坡滑坡深层含碎石滑带土为研究对象，采用自行设计的蠕变试验设备开展原位含碎石滑带土的大型剪切蠕变试验，立足于时效曲线中“粘-滑”蠕变特征，建立粘滑蠕变参数。结合CT扫描，无损动态获取滑带土细观组构，基于碎石实际轨迹和时效曲线，提出考虑碎石和粘滑率的粘滑蠕变判据模型，研究碎石性状与粘滑蠕变动态关联特征。基于近10年库水位极端动态变化数据开展室内粘滑蠕变试验，构建“稳态渗透-极端动态渗流-碎石性状”多因素耦合的粘滑蠕变模型和蠕变参数，从而揭示极端动态渗透压下含碎石滑带土的非线性粘滑蠕变演化机理，提出考虑“粘-滑”蠕变特征的滑带土时效变形预测修正方法，含碎石滑带土的“粘-滑”蠕变演化机理精准研究将推动长江经济带的发展，为水库滑坡的预报预警提供理论依据。

在三峡库区，水库水位周期性涨落情况下含碎石滑带土的粘滑蠕变特性直接影响水库滑坡时效变形的精确预测。因此，探索动态渗透压下含碎石滑带土的非线性粘滑蠕变演化机理具有重要的理论研究与工程实际意义。.本项目采用野外工程地质调绘、原位试验、室内试验、理论分析和数值模拟等手段，以三峡库区黄土坡滑坡含碎石滑带土为研究对象，基于空天地采集的滑坡变形监测数据，采用自行设计、改造的大尺寸直接剪切蠕变试验设备、变孔压三轴蠕变试验设备、变孔压直剪试验设备等开展不同尺寸的含碎石滑带土在不同固结压力、应力路径、渗透压和动态孔隙水压力下的蠕变和应力松弛试验，根据不同蠕变试验的时效曲线中粘滑蠕变特征，建立滑带土的粘滑蠕变模型。.蠕变试验前后，选取具有代表性的单元土体，采用CT扫描、XRD、XRF、SEM等试验和数字图像处理技术，无损动态获取含碎石滑带土组成和细观结构。基于滑带土中碎石性状采用FEM和亚塑性模型模拟含碎石滑带土的变形和强度规律。基于不同试验的蠕变曲线、时效曲线和本构模型，提出考虑碎石和粘滑的粘滑蠕变判据，研究碎石性状、不同固结压力、不同孔隙水压力与滑带土粘滑蠕变关联特征。.基于近年库水位极端动态变化数据，采用重塑滑带土开展室内粘滑蠕变试验，研究稳态渗透压下滑带土的蠕变，不同频率、不同幅值和不同循环次数下滑带土的蠕变，构建“稳态渗透-极端动态渗流-碎石性状”多因素耦合的粘滑蠕变模型和蠕变参数，从而揭示极端动态渗透压下含碎石滑带土的非线性粘滑蠕变演化机理。分别采用经验公式、元件模型建立滑带土的蠕变本构模型，提出考虑“粘-滑”蠕变特征的滑带土时效变形预测修正方法。含碎石滑带土的“粘-滑”蠕变演化机理研究成果将推动长江经济带的发展，为水库滑坡的形成演化机理、预报预警提供理论依据。