基于宏细观力学的尾矿非线性力学特性研究

Tailings reservoir has been one of main risk sources in metal mines. Mechanical property of tailings is the basis of disaster prevention research and safety assessment of tailings reservoir. Therefore, in this project, the integrity of laboratory experiment, theoretical analysis and practical engineering cases survey will be adopted for investigating the variation and influences of the engineering mechanical properties caused by particle size, moisture content and layered structure of coarse and fine of tailings from both macro- and micro- mechanical scales. Detailedly, the characteristics of interaction between particles under load, the migration law of pore water and their effect on meso-structure of tailings, the meso-mechanics behavior characteristics of coarse and fine layered structure of tailings, and the influence on meso-mechanics behavior of moisture content and particle size of tailings will be studied with a self-developed observation testing apparatus for micro-mechanics and deformation of tailings. According to the test results, the nonlinear characteristics of deformation evolution of tailings with different particle sizes and layered structure of coarse and fine tailings, as well as their meso-mechanics behavior mechanisms will be obtained based on the fractal theory and mechanical theory of granular matter. Moreover, the numerical simulation software of PFC2D will be used to analyze the deformation of tailings dam and to find out the failure characters in order to explore the deformation failure mechanism of tailings dam from mesoscopic view. The results will not only expand meso-mechanics knowledge of tailings, but also provide theoretical guidance for the safe operation of tailings dams and the sound construction as well as harmonious development of metal mines.

尾矿库已成为金属矿山最大的危险源之一。尾矿的力学性质是尾矿库灾害预防研究与安全评估的基础。为此，从材料的宏细观力学角度，采用室内实验、理论分析和工程实例相结合的综合性研究方法，研究尾矿粒径、含水率及粗细分层结构等因素对尾矿工程力学性质的影响及变化特征。即利用自主研发的尾矿细微观力学与形变观测试验装置，研究上覆荷载作用下尾矿颗粒之间的相互作用特性、孔隙水的运移规律及其对尾矿细观结构变化的影响、粗细尾矿分层结构体的细观力学行为特征、含水率与粒径对尾矿细观力学行为特性的影响等。并结合实验结果，基于分形理论与颗粒物质力学理论，探讨不同粒径尾矿及粗细分层结构体受载非线性变形演化特征及其细观力学行为机制。进而采用颗粒流模拟软件分析尾矿坝变形特性，找出失稳破坏特征，从细观力学的角度探索尾矿坝变形破坏机理。研究成果不仅能丰富尾矿的细观力学知识，而且可为尾矿库安全运营、建设平安和谐矿山提供理论指导。

项目从材料的宏细观力学角度，通过室内土工试验、尾矿细观力学试验、堆坝物理模型试验及数值模拟的方法，并结合理论分析，研究尾矿宏观工程力学性质，尾矿受载非线性变形演化特征及其细观力学行为机制，孔隙水运移及对尾矿细观结构的作用，及尾矿坝的变形破坏特性。研究获得受粒径、含水率、密度及分层结构等因素影响的尾矿宏观力学性质变化规律；得到全尾矿、不同粒径尾矿、粗细尾矿分层结构体的细观结构特征、细观结构变形演化规律、颗粒位移特性、及局部应力响应特征；揭示荷载与孔隙水综合作用下非饱和尾矿与饱和尾矿中孔隙水运移规律，及其对尾矿细观结构变形演化和颗粒分布的综合影响机制，提出尾矿坝体实际浸润线的计算模型。同时，基于颗粒物质力学理论，获得尾矿颗粒排列演化机理、颗粒接触力传递规律、及其宏观等效力学响应机制；基于分形理论，揭示尾矿孔隙结构与骨架颗粒结构（团聚）的分形几何特征，分析得到尾矿细观结构受载变形演化分形特性，并建立尾矿细观结构分形维数与宏观力学参数的经验关系模型。并且，结合尾矿库颗粒流数值模拟结果，揭示尾矿坝颗粒接触应力分布特征与坝体结构变形破坏细观力学机理。最终，揭示尾矿宏细观力学特性受含水率、颗粒粒径、分层结构等因素影响机制，实现尾矿坝宏观等效力学稳定的预测分析。研究成果有助于丰富和发展尾矿细观力学知识、提出有效改善尾矿库细观尺度颗粒结构稳定的尾矿库安全运营措施，对于科学缓解尾矿库失稳溃坝问题，建设平安和谐矿山均具有重要的理论与实际意义。