小秦岭矿区矿渣泥石流发育特征及启动机理研究

发布时间：2019-02-20 09:17

【摘要】：矿渣泥石流是指由矿区采矿活动所产生的废弃矿渣不合理堆放而引起的泥石流,是典型的人为泥石流。与自然泥石流相比,矿渣泥石流的发育特征与启动机理有着明显的不同。本文以小秦岭金矿区(灵宝市内的区域)为研究对象,通过对区内矿渣泥石流物源(渣堆)的调查研究,总结分析了区内矿渣泥石流的发育特征,发现矿渣泥石流的分布规律与人类活动相关性密切,渣堆的颗粒级配与一般水石流相比有着颗粒大、颗粒级配跨度大的特点。通常情况下,在粗粒土中,颗粒粒径大于5mm的颗粒含量大于70%时,粗粒土中会形成骨架结构,其渗透性能会有明显的上升变化。针对区内渣堆中大于5mm粒径的颗粒含量大于85%的情况,为进一步研究渣堆内部结构,利用PFC颗粒流程序对区内物源(渣堆)进行模拟,建立了渣堆边坡模型。重点对渣堆的骨架结构特征进行了模拟、分析,发现大粒径的颗粒在渣堆中形成了明显的骨架结构。渣堆在天然状态下坡脚接近天然休止角,但渣堆内部并没有差异应力现象,可见具有良好渗透性能的渣堆在天然状态下较为稳定。泥石流的启动是泥石流研究的重点,底床坡度、水源补给和颗粒级配在泥石流的启动过程中起着决定性作用。水源补给是泥石流启动中最为直接诱发因素,本文在研究矿渣泥石流的启动过程中,利用PFC颗粒流程序建立了区内典型渣堆的二维数值模拟模型,研究在不同控制降雨强度条件下,降雨对渣堆启动的效果及作用机理。通过分析数值模拟的结果得出,在降雨强度相对较小时(50mm/12h),即使长时间的降雨,也只能对渣堆产生较为微弱的启动作用,且在此时渣堆的尾部(底部)先于其他位置启动;在降雨强度相对较大时(140mm/12h),降雨对渣堆的启动作用十分明显,渣堆一旦起动启动,启动加速度较快,破坏力强,且渣堆的顶部先于其他位置启动,起动时有明显成层现象。
[Abstract]:Slag debris flow is a typical man-made debris flow caused by unreasonable stacking of waste slag produced by mining activities in mining area. Compared with natural debris flow, the development characteristics and start-up mechanism of slag debris flow are obviously different. In this paper, taking the area of Xiaoqinling Gold Mine (the region of Lingbao City) as the research object, through the investigation and study of the source (heap of slag) of the debris flow in the area, the development characteristics of the debris flow in the area are summarized and analyzed. It is found that the distribution of slag debris flow is closely related to human activities, and the particle gradation of slag heap has the characteristics of large particle size and large particle gradation span compared with general water and stone flow. In general, when the particle size of coarse grained soil is larger than 70% of 5mm, the skeleton structure will be formed in coarse grained soil, and the permeability of coarse grained soil will change obviously. In order to further study the internal structure of slag reactor, in order to further study the internal structure of slag reactor, the material source (slag reactor) was simulated by PFC particle flow program, and the slope model of slag reactor was established. The characteristics of the skeleton structure of the slag reactor were simulated and analyzed. It was found that the large particle size formed an obvious skeleton structure in the slag reactor. The sloping foot of the slag pile is close to the natural angle of repose in the natural state, but there is no differential stress phenomenon inside the slag pile, so the slag heap with good permeability is stable in the natural state. The start-up of debris flow is the focus of debris flow research. The slope of bottom bed, water supply and particle gradation play a decisive role in the starting process of debris flow. Water recharge is the most direct inductive factor in the start-up of debris flow. In this paper, the two-dimensional numerical simulation model of typical slag pile in the area is established by using PFC particle flow program in the process of starting slag debris flow. The effect and mechanism of rainfall on the start-up of slag heap under different rainfall intensity control conditions were studied. By analyzing the results of numerical simulation, it is concluded that even if the rainfall intensity is relatively low (50mm/12h), even if the rainfall lasts for a long time, it can only produce a weaker starting effect on the slag heap. At this time, the tail (bottom) of the slag heap starts before other positions; When the rainfall intensity is relatively large (140mm/12h), the effect of rainfall on the start of slag reactor is very obvious. Once the slag reactor starts, the starting acceleration is faster and the destructive power is strong, and the top of the slag reactor starts before other places. There is obvious stratification phenomenon when starting.
【学位授予单位】：华北水利水电大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.23

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