Floor Water Inrush Prediction Based On Risk Evaluation And Catastrophe Theory

In North China coalfields, water disasters issues are quite general and serious,especially floor water inrushes from Ordovician limestone aquifers often cause heavycasualties and property losses. Scientific risk assessment of coal floor water burstingis an important foundation for the basic premise of the mine water disaster preventionand safe mining achievement. Therefore, to study the risk evaluation method of coalfloor water inrush is of certain practical significance. Xin’an coal mine′shydrogeological condition is very complex, because of that there was once anextremely serious water inrush accident happened due to an uncovered small fault inⅡ1coal seam floor. Therefore, the method studied in this thesis will be applied to therisk assessment practice of Xin’an coal mine water inrush, which is not only good forthe mine production safety, but also helps to validate the evaluation model andunderstand the evaluation methods.Risks fitting method and catastrophe theory method-two risk evaluation methodsare addressed based on the study of mine water inrush formation conditions andinfluencing factors. Risk fitting is an approach based on the risk theory to establishcoal floor water bursting risk assessment model. Fitting risk also works from risktheory, first deduces water inrush risk mathematical expressions, and then usingmultiple linear regression method fits expression coefficients according to knownwater bursting point information from the coal mine, finally establishes evaluationmodel. Multi-source information fusion with ArcGIS functions is also used in thisresearch to overlay thematic maps of risk influencing factors regarding to theevaluation model. Then water inrush risk assessment is carried out in accordance withthe overlaying results. Catastrophe theory method is a method based on catastrophetheory. This method determines the state variables and primary and secondary controlvariables through the study of floor water inrush catastrophe mechanism, thenequilibrium surface equations is proposed according to cusp catastrophe model andnew equation expressions are obtained after coordinates conversion (state variablesand primary and secondary control variables coordinates). Equations groups areconstructed with the new coordinates to solve the coefficient of surface equation andnew origins of the coordinates, which will be identified by known water inrush pointsinformation. In the end, according to the root criterion in new coordinates, water inrush risk assessment model is established and applied for the assessment.This thesis adopts risk fitting method, catastrophe theory method, vulnerabilityindex method and water inrush coefficient method respectively to evaluate Xin’an Ⅱ1floor water inrush risk. Except for the water inrush coefficient method, the evaluationresults of the other three methods fit well with the actual water bursting points.Through the research of these four risk assessment methods and comparison ofevaluation results, complex floor water inrush mechanism can be better understood.The results of this research has some theoretical significance and practical value fordeep and high pressure water safe mining and long-term forecast of mine waterinrush.