薄基岩浅埋深矿区地表开采沉降预测及影响因素分析

Prediction and Analysis to Affecting Factors of Surface Mining Subsidence in the Mining Area of Shallow Coal Seam with Thin Bedrock

目前我国西北部地区浅埋深薄基岩开采区地表沉降现象日益严重。以鄂尔多斯某矿区为例,基于该矿区覆岩性质、地质条件、开采技术条件、地表沉降点观测数据,运用概率积分法对首采区的地表开采沉降规律进行了分析预测,并对该矿区典型的薄基岩浅埋深开采地表沉降的主要影响因素进行了分析。结果表明:1概率积分法的矿区开采沉降预测结果与实测数据基本吻合,表明采用该方法预测矿区地表移动参数是可行的;2由于矿区整体构造简单,且工作面内煤层基本呈水平分布,煤厚、采深、倾角等因素变化较小,综合分析认为顶板松散层基岩厚度比(HS/HJ)、开采强度(工作面推进速度)是该矿区地表沉降的主要影响因素;3对工作面走向的顶板松散层基岩厚度比(HS/HJ)曲线、开采强度(工作面推进速度)曲线与地表沉降量曲线进行了对比分析,认为松散层基岩厚度比(HS/HJ)、开采强度(工作面推进速度)对矿区开采沉降具有相反的作用,且开采强度(工作面推进速度)对矿区开采沉降的影响较大。上述分析结论对于地质构造稳定的鄂尔多斯地区矿区开采沉降分析预测有一定的参考价值。

At present,surface subsidence of coal mining is an increasing serious phenomenon,especially for shallow coal seam with thin bedrock in northwest China. Taking the mining area of a mine in Ordos as an example,the regularity and affecting factors of surface mining subsidence after mining of the first mining working face are analyzed. Based on the properties of the above strata,geological conditions,mining technical conditions and surface subsidence observation data of the mining area,the regularity of the first mining working face is analyzed by using probability integral method,and the main affecting factors of the surface subsidence in shallow coal seam with thin bedrock are also discussed in depth. The result show that： 1the prediction results of the surface mining subsidence by using probability integral method is consistence with the measure data basically,therefore,it is feasible to predict the surface movement parameters in the mining area by using probability integral method;2the whole structure of the mining area is relatively simple,the coal seam of mining working face is distributed in horizontal,so,the factors such as thickness,mining depth,dip angle are changed slightly,through analyzing the above factors,it is believed that the ratio of the loose layer thickness and bedrock thickness（ HS/ HJ） and mining intensity（ advancing speed of working face） are the main affecting factors of the surface subsidence in the mining area; 3the ratio of loose layer thickness and bedrock thickness（ HS/ HJ）,mining intensity（ advancing speed of working face） curve and surface subsidence curve are analyzed,the roles of the ratio of loose layer thickness and bedrock thickness（ HS/ HJ） and mining intensity（ advancing speed of working face） to surface mining subsidence in mining area are opposite,the influence of mining intensity of（ advancing speed of working face） is greater than the ratio of loose layer thickness and bedrock thickness（ HS/ HJ） to surface subsidence in mining area. The above research results have certain reference value for analysis and prediction of the mining surface mining subsidence in Ordos area with stable geological structures.