Research On Disaster Mechanism&Prevention And Control Induced By Groundwater In The Groundwater Abundant Mines

Owing to the fact that the abundant water mines have large water flow and complex hydrogeology condition, the groundwater disaster often cause serious human casualties and economic losses. Therefore, a large amount of expense must be paid to prevent and control these sorts of disaster, some mines even have to be forced to suspend production activities. With the rapid development of the mining industry, the number of excavated underground abundant water mines are gradually increasing, groundwater disaster has gradually become the bottleneck constrains of underground mining development. In this paper, taking groundwater disaster in abundant water mines as the research object, on-site information collection and surveying, field test, system theories and numerical calculations have been done for revealing the mechanism of groundwater disaster, the criterion of drainage-groundwater system failure disaster was founded, then distribution characteristics of groundwater disaster in abundant groundwater mines have been deeply analyzed, the method system of groundwater disaster prevention and evaluation model of disaster failure possibility have been put forward, a series of meaningful research achievements has been obtained consequently.(1) Based on systematic theory, the concept of drainage-groundwater mining system has been put forward according to the actual abundant groundwater mining environment. Model of the drainage-groundwater mining system and its solution method have been built by utilizing mathematical technique. The structural relationship of external factors and internal conditional variables (coefficient of permeability, hydraulic gradient and aquifer thickness about groundwater, drainage boundary, area of recharge boundary) about the system has been confirmed in the model, which drawn the conclusion that drainage-groundwater system is stochastic and dynamic.(2) The failure mechanism of drainage-groundwater mining system in abundant water mines was concluded by two points. One is that the external flow caused by random effect exceeded the system allowance pressure. As a result, the water level inside the system exceeded the safety level, so system disaster occurred. The other is that the water controlling structure or drainage system failed within the mining environment system, leading to the new water flow recharge or disrecharge which resulted in water level exceeding the safety water level, and the process can be called the disaster causing by system internal structural failure. The criterion of drainage-groundwater system failure disaster was founded.(3) The application research about failure mechanism of drainage-groundwater environment in water abundant mines was brought out. The disaster mechanism and failure criterion were applied in a mine instance. The state of the groundwater environment system was discriminated and the effect of disaster influencing factors to system state was analyzed. The practical application of failure criterion of the groundwater environment system showed that the model and criterion built could effectively discriminate the system's disaster state. The analysis of disaster factors showed that disaster occurrence was mainly controlled by safety water level, random effects and flow difference in system. The change of flow difference in system had the greatest impact on system failure, followed by safety water level, and finally by random effects of system.(4) The connotation of analyzing drainage-groundwater system's failure in abundant water mines was made clear, the calculation method of failure probability of drainage-groundwater system in abundant water mines was founded, while the prediction method of disaster distribution within corresponding failure probability was built, too. The above method was applied into a disaster prediction instance, and prediction result was consistent with the actual disaster distribution, which confirmed the validity of the founded prediction method.(5) The integrated control method and its effectiveness research were carried out within engineering application. The following conclusion was obtained:when groundwater flow belongs to dynamic water supply, the drainage ability of drainage system was limited. So, drainage system and impervious curtain should be jointly utilized.(6) The assessment index system and model of failure possibility of the groundwater system in groundwater abundant mines were established. The index system was divided into3levels and12factors. All factors were as follow:the offset distance between boundary and drainage drift, effect of curtain closure, stable level of groundwater, the maximum capability of bearing water in drainage facilities, service life of drainage facilities, collapse, rainfall, permeability coefficient, interception capacity of closure drift, drift gushing, condition of drainage facilities, cross-section of drift. The index system generally summarized the hazard breed environment, hazard bearing body, hazard induced factors. Fuzzy comprehensive evaluation method and projection pursuit clustering evaluation method based on genetic algorithms were respectively used for establishing corresponding failure possibility assessment model. The application results indicated that models both could effectively realize the possibility degree evaluation of the groundwater system failure in groundwater abundant mines, projection pursuit clustering evaluation model based on genetic algorithms has strong discreteness in classification results, while fuzzy comprehensive evaluation model has relatively weak discreteness in classification results. Therefore, projection pursuit clustering evaluation model based on genetic algorithms overwhelmed in determining evaluation degree, besides, the weights of genetic algorithms evaluation method are objective which are rely on the sample sets.