基于降雨条件和堆积特征的内排土场泥石流启动规律研究

With the sustainable mining of open-pit mine resources, it is well known that the problems such as great amount of dumping and large ground area demand are ubiquitous, internal waste dumps have become more and more common. The mudflow of internal waste dump is one of the most serious disasters brought by rainfall, application of starting law of mudflow is an effective measure to avoid and mitigat loss caused. However, it is found that there are the great differences between the mudflow of waste dump and traditional debris flow, and study on this aspect is rarely. Taking typical mine mudflow of internal waste dump as an example, using the research method of field investigation、model experiment in laboratory、theoretical and numerical simulation analysis, special material sources and rainfall characteristics on starting of the mudflow of internal waste dump can be find out. Study on the relationship of starting of the mudflow with rainfall process、soil property and accumulation system, it is easy to obtain each factor influential action on starting of the mudflow of internal waste dump. Research on the mudflow of waste dump outbreak process under rainfall infiltration based on the combination of unsaturated soils theory、orthogonal experiment and numerical simulation, it is mutual confirmation between theory and practice using similarity simulation experiment.it will revealing starting law of the mudflow of internal waste dump with theoretical and practical significance. The successful execution of this project provides the fundamental basis for starting prediction of internal waste dump mudflow and dump construction, this study has important theoretical significance and practical use-value.

随着露天矿的持续开采，排土总量逐渐加大，为减少占地逐渐转为内排，降雨诱发内排土场泥石流是最主要的矿山灾害类型之一，泥石流启动规律的有效应用是矿山防灾减灾的重要手段。然而内排土场泥石流与传统的泥石流差异巨大,有针对的研究开展较少。本项目以典型矿山内排土场泥石流为研究对象，采用现场调查、模型实验、理论及数值模拟分析相结合的方法，查清内排土场泥石流暴发的特殊物源条件和降雨特征。研究降雨过程、土料性质及堆积方式与泥石流启动的关系，获得各要素对内排土场泥石流启动的影响作用。结合非饱和土渗流理论、正交实验及模拟技术，研究降雨入渗条件下内排土场泥石流的暴发过程，并利用相似模拟实验进行理论与实践互证完善，揭示具有理论和实践意义的内排土场泥石流启动规律。本项目的成功实施能为内排土场泥石流启动预测及排土场建设提供基础依据，具有重要的理论意义和实际应用价值。

降雨诱发泥石流灾害是内排土场的主要破坏形式。本项目以典型露天矿内排土场为研究对象，采用现场调查、模型实验、理论及数值模拟分析相结合的方法，系统研究了降雨和堆积特征条件下的内排土场泥石流启动规律，获得的研究成果主要为：.（1）内排土场泥石流暴发与降雨条件正相关、与排土时间呈指数递减。提出了基于系统动力学的地质灾害链及演化规律。内排土场土料工程地质性质较差，渗透系数较小，结构性差，在降雨条件下极易引起失稳破坏形成泥石流。.（2）依据Fredlund的扩展莫尔-库仑准则，获得了土料的非饱和抗剪强度特征。土料抗剪强度随基质吸力而增加的速率变化较大，其非饱和抗剪强度受降雨入渗过程中引起内部含水率的变化影响较大。土料黏聚力、内摩擦角对含水率比压实密度更敏感，土料含水率与压实密度的相互作用不显著。获得了基于Van-Genuchten模型和Richards模型的土水特征曲线和渗透系数预测方法。.（3）以设计的物理模拟平台和非饱和土理论为基础，获得了坡面降雨入渗特征和入渗量求解的理论方法、泥石流启动的影响因素和速度场的分布规律。结合数值计算方法，掌握了内排土场的坡面侵蚀破坏模式划分为：雨滴溅蚀—溅蚀沟—溯源侵蚀—侵蚀沟—侵蚀破坏5个阶段，摸清了基于降雨入渗和堆积特征条件下内排土场泥石流的暴发规律，获得了内排土场泥石流启动的水-土力学耦合机理。.（4）以相似试验原理为基础建立了内排土场相似试验模型，结合内排土场边坡现场变形监测、动态记录内排土场变形特点，进行了成果的对比互证，获得了降雨方式和堆放设计标准对泥石流启动的影响规律，并以此提出了泥石流危险范围预测和内排土场的排土方法。.取得的内排土场泥石流启动规律研究成果，能为泥石流暴发机理的研究提供支撑，也能为露天矿山开采过程中防灾减灾工作的开展提供依据，具有一定的理论价值和应用前景。