Risk Judgement And Prevention On Debris Flow In 2～# Waste-dump Of Nanfen Iron Mine

Debris flow has been paid close attention as one kind of hazards around all of the world. It often causes large damage to ecological environment, and human's production, property and life, for its Fast velocity, surprise breakout, severe damage. Debris flow breakout in mine frequently, because unreasonable emission in the process of mining.Nanfen opencast mine is the largest black metallurgy mine in our country and the important iron stone production base of iron and steel plant in Benxi. There is incipient fault of debris flow in 2# waste-dump of Nanfen iron mine because its high shoulders height, heavy rainfall and man's activity. So it active demands to make clearly the development of debris flow in the area, judge its risk and bring it under control. The subject investigated in the paper is the debris flow in 2# waste-dump of Nanfen iron mine.This paper expects studying of risk judgement and prevention, in order to protect residents and mine production, at the same time to probe into the method of risk judgement of debris flow.The paper consist of a prolegomenon, geology of 2# waste-dump,formation factor and mechanism of debris flow, risk judgement and prevention. Its main contents were described as following:(1) In first chapter of this paper, author described the study purpose of risk judgement and prevention of debris flow. Furthermore, present situation and development trends of the study field are analyzed. Author also described the work processes, completed study contents and methods.(2) In chapter two, author not only introduced the geography, geology in the area and engineering geology conditions. but also detailed discussed environmental background for debris flow formation in 2# waste-dump.(3) On the basis of the field survey, data collection,development characteristic was discussed. Author analyzed the formation factor of debris flow whichwere terrain condition, reserves, rainfall and human activity; and discussed the mechanism about the debris flow which conversed from landslides and attraction of gravity.(4) The risk of debris flow in mine was judged by the one- layer and multi-layer fuzzy comprehensive evaluation. There were nine risk factors including reserves,basin perimeter,longitudinal river slope,maximal quantity of rainfall in 24 hour,bending coefficient,percentage of vegetation,gradient of slope,lithologic character and slope collapsing degree. The risk degree was divided fourth level and the evaluation standard ofdebris flow in mine was builded. The factor weights were calculated by the analytical hierarchy process and the risk of debris flow in mine was judged by the fuzzy comprehensive evaluation. The judgement system analytical hierarchy process model was builded which total target was the risk of debris flow, first layer were earth storage situation, geology in the area, exogenic geological process, stream tectonic characteristic, second layer were risk factors. The result of tow kinds of fuzzy comprehensive evaluation was approximation, which showed that the debris flow risk degree in 2# waste-dump wasâ…¢.(5) On the basis of risk judgment, prevention measures of debris flow were supplied. Drain ditch and gully control dam were been designed on the principle of biologic management combined project which have priority.This study show that the results of risk fuzzy comprehensive judgment of debris flow in 2# waste-dump coincide with fact. It is a meaningful discussion that to inject multi-layer fuzzy comprehensive evaluation into an actual example of mine debris flow. Risk judgement model and standard of debris flow which are put in use in 2# waste-dump successful and worth to further study in risk judgement of other similar debris flow have a great meaningful in theory and practice.