尾矿库堆坝静态液化失稳触发灾变渐进演化机理研究

According to the engineering demand of the safe construction and run of tailing dam, the soil element test, centrifuge test, theoretical analysis and numerical simulation are used this research to investigate the static liquefaction of tailing material and the evolution of the catastrophic failure of tailing dam. By employing stress-path triaxial tests, true triaxial tests and unsaturated triaxial tests, the static liquefaction of saturated and unsaturated tailings under real stress and hydro-air condition are obtained. By analyzing the instability behaviour of the constitutive relationship, the critera of static liquefaction is proposed, and the trigger mechanism of static liquefaction under hydraulical-mechanical condition is obtained. Based on the centrifuge model tests and the numerical modeling of the static liefaction, the progressive failure mechanism of the tailing dam is investigated. Based on the strength parameters of tailing and failure mechanism of the tailing dam under static liquefaction condition, a theoretical model to assess the stability of the tailing dam will be built. The research results can provide useful theoretical supports for the stability analysis and safety control of the tailing dam, and also can provide guidance for the project design.

针对当前尾矿库建设及运行安全的工程需求，本项目通过土单元试验、离心模型试验、理论分析和数值模拟，对尾矿料静态液化失稳特性及堆坝失稳触发灾变渐进演化机理进行研究。通过应力路径三轴、真三轴和非饱和土三轴试验，获得实际应力和水气条件下尾矿料静态液化失稳特性和强度表征；提出尾矿料静态液化失稳理论判别准则，揭示水气耦合条件下静态液化触发机制，建立固液气耦合条件下的静态液化数值模拟技术；基于尾矿堆坝失稳过程的精细化离心模型试验和静态液化数值模拟，揭示尾矿堆坝静态液化失稳触发灾变的渐进演化机理；基于静态液化条件下尾矿料强度表征及堆坝破坏模式，建立尾矿堆坝稳定性分析方法，研究成果可为尾矿库安全评估和治理提供理论支撑，并为工程设计提供指导。

我国是目前世界上尾矿堆存量最大的国家，尾矿坝多通过上游法筑坝，坝体沉积密度偏低、浸润线偏高，渗流难以控制，因而失稳概率较高。随着我国矿产资源持续开发，尾矿产量仍不断增加，尾矿库安全仍面临着巨大挑战。结合我国尾矿库建设及运行安全的实际需要和已有研究基础，针对尾矿料静态液化失稳特性及尾矿堆坝灾变渐进演化机理开展深入研究。通过各向同性和K0固结不排水三轴剪切试验，获得尾矿料静态液化失稳特性和强度表征，并获得了细颗粒含量对静态液化失稳的影响规律。考虑尾矿料颗粒级配组成情况，修正材料状态参数构建了一个材料状态相关临界状态三维本构模型，基于二阶功准则提出了静态液化失稳判别准则并进一步推广到考虑液气耦合影响。通过开展尾矿库堆坝失稳过程精细化离心模型试验，获得了尾矿库堆坝灾变渐进演化机制并确定了其最终破坏模式。构建了尾矿料静态液化失稳数值模拟方法，获得了尾矿坝失稳演化机制，最终建立一个考虑尾矿料静态液化失稳影响的堆坝边坡稳定性理论分析模型。研究成果可为我国尾矿坝建设及安全运营提供理论依据，并可推广用于建筑余泥渣土堆积体稳定性分析，具有一定理论内涵和工程应用价值。