渗透-组构-应力作用下的消落带滑带土弱化机理研究

For large water conservancy and hydropower project, long-term stability of the reservior bank landslide is a key scientific problem. The aim of this project is to analyse the weakening mechanism of slip soil of hydro-fluctuation zone in Huangtupo landslide in Badong by considering the significant cyclical fluctuations of water in Three Gorges Reservoir. By using osmometric modeling, mechanical tests, micro-test analysis and numerical simulation, dynamic response of slip soil in hydro-fluctuation zone, namely changes in composition, microstructure, hydraulic properties and mechanical characteristics, can be revealed under coupling action of dynamic osmometric pressure（change osmometric pressure substantially，under repeated loop "low-high-low-0-low-high-low", to simulate the significant fluctuation of reservoir water）with stress. In order to establish microstructure evolution model of slip soil, digital image processing technology is used to figure out its micro-structual features firstly. Then the mircostructure parameters are quantized and coupled with mechanical effect. Finally,combining System Dynamics Theory with the numerical simulation of PFC3D, microstructure evolution model of slip soil is established. Based on Generalized Rough Set Theory, the multi-source information is heterogeneously integrated to establish the micro-macro time-varying mechanical model of slip soil.On basis of the above research, we can find out the weakening mechanism of slip soil under coupling action of seepage-fabric-stress by combining with the result of numerical simulation. The achievement of the project could provide theoretical support to explore the evolution process of reservior bank landslide, to evaluate its long-term stability reasonably and to effectively control bank landslide.

针对大型水利水电工程中库岸滑坡长期稳定性研究中的关键科学问题，选取三峡库区巴东县黄土坡滑坡滑带土开展库水周期性大幅涨落条件下的消落带滑带土弱化机理研究。通过渗透模拟、力学试验、微观测试及数值模拟等技术手段，揭示滑带土在动态渗透压（渗透压"低-高-低-0-低-高-低"动态变化，反复循环进行）与应力耦合作用下物质组成、微观结构、水理特性和力学特性的动态响应规律。利用数字图像处理技术获取滑带土的微观结构特征，通过微观结构参数定量化与力学效应耦合分析，以系统动力学理论为基础，并结合PFC数值模拟，建立滑带土微观结构演化模型。基于广义粗集理论对获取的多源信息进行异类融合，建立微观-宏观信息融合的滑带土力学时变模型。在此基础上，结合滑带土弱化过程数值模拟成果，揭示渗透-组构-应力耦合作用下的消落带滑带土弱化机理。为探究库岸滑坡的演化过程、合理进行库岸滑坡长期安全性评价、有效进行库岸滑坡防治提供理论支撑

针对大型水利水电工程中库岸滑坡长期稳定性研究中的关键科学问题，选取三峡库区巴东县黄土坡滑坡滑带土开展库水周期性大幅涨落条件下的消落带滑带土弱化机理研究，主要研究内容包括：1）渗透-组构-应力作用下滑带土渗透模拟试验；2）渗透-组构-应力作用下的滑带土宏观力学特性及水理特性研究；3）渗透-组构-应力作用下的滑带土物质组成及微观结构特征演化研究；4）基于微观-宏观的渗透-组构-应力作用下滑带土弱化机理及力学模型研究；5）渗透-组构-应力作用下滑带土弱化机理的应用。取得的成果为探究库岸滑坡的演化过程、合理进行库岸滑坡长期安全性评价、有效进行库岸滑坡防治提供理论基础支撑。取得的重要研究进展如下：.1）为弥补传统渗透和干湿循环仪器的缺陷，解决渗透-组构-应力作用下滑带土渗透试验模拟的核心问题，提高试验效率和试验合理性、降低试验成本，自行设计了两款具有较广泛应用前景的新型试验仪器。.2）通过渗透模拟、力学试验、微观测试及数值模拟等技术手段，揭示了滑带土在动态渗透压与应力耦合作用下物质组成、微观结构特征、水理特性和宏观力学特性的动态响应规律。.3）基于分形理论利用数字图像处理技术从微观测试数据中挖掘、提取和定量化滑带土微观结构特征，获取了大量的渗透-组构-应力耦合作用下滑带土微观结构参数，并在此基础上建立了渗透-组构-应力耦合作用下滑带土微观结构演化模型。.4）基于灰色系统理论对获取的滑带土微观结构参数和宏观力学参数进行异类融合与分析，基本揭示了渗透-组构-应力耦合作用下的消落带滑带土弱化机理，并建立了渗透-组构-应力耦合作用下滑带土力学模型。.5）选取黄土坡滑坡临江1#崩滑体、黄土坡滑坡临江2#崩滑体、凉水井滑坡和白水河滑坡作为研究成果应用对象，将研究得到的消落带滑带土弱化机理成功地应用到这些滑坡的稳定性评价、可靠度分析和演化过程分析当中，验证了所得成果的有效性和实用性。