含水层与多烧变岩含水体互层下煤层顶板突(涌)水风险性预测

Prediction of roof water inrush risk under the complex condition of interbedded aquifer and multi burnt rock aquifers

陕北矿区煤层顶板存在多层富水性极不均一的烧变岩含水体,与裂隙发育的风化基岩含水层上下互层叠置,为了准确评价两者的富水性和科学预测煤层顶板突(涌)水风险性,以张家峁井田5^(-2)煤为例,结合风化基岩和2^(-2)煤、3^(-1)煤、4^(-2)煤烧变岩的水力特征、含水层厚度和岩性差异选取富水性评价指标,采用AHP-熵权组合赋权法改进指标确权方法,准确刻画目标含水层的空间富水特征;提出基于修正系数的导高计算方法,以导水裂隙进入含水层程度为依据插值生成顶板冒裂稳定性分区图;两种地学信息叠加,对5^(-2)煤顶板突(涌)水风险性分级、分区预测。研究成果为煤层顶板多含水层非连续互层复杂地质条件下突(涌)水风险性预测提供了一种新方法。

There are many layers of burnt rock aquifers with extremely uneven water abundance which is interbedded and overlapped with fissure developed weathered bedrock aquifers in the coal seam roof of the northern Shaanxi mining area,in order to accurately evaluate the water abundance of both and scientifically predict the water inrush hazard of coal seam roof,5^(-2)coal in Zhangjiamao mine field is taken as an example.The evaluation indicators of water abundance are selected based on the hydraulic characteristics,aquifer thickness and lithologic difference of weathered bedrock and burnt rock of 2^(-2)coal,3^(-1)coal and 4^(-2)coal.To improve the method of weight determination,comprehensive weighting method based on AHP and the entropy weight are adopted to accurately characterize the spatial water-abundance characteristics of the target aquifers.The calculation method of the guided height based on the correction coefficient is put forward and the thickness data of the guided fractures entering the aquifer are drawn into the partition diagram of the roof cracking stability.By superimposing two kinds of geospatial information,the classification and zoning prediction of roof water inrush risk of 5^(-2)coal in Zhangjiamao Coal Mine are realized.The research result provides a new method for predicting roof water inrush risk under the complex geological conditions of multiple aquifers discontinuous interbedded.