地下煤炭资源被人工采出以后,因上覆岩层的失稳、垮落、重新密实而使地表出现开裂、塌陷和变形等地质灾害。传统的研究煤矿开采沉陷的方法主要有地质法、实地监测法、物理和数值模拟法等,这些方法耗费大量人力、物力、财力,且部分参数的获取十分困难。为了获得在煤矿开采区域内地表沉降情况的准确信息,本文利用采动卸压原理和"三带"模型,以湖南省金竹山矿业公司的土珠煤矿开采沉降实况为研究背景,分析其地下采煤时地表裂缝与沉降的发生机制与特征。提出在开采垂直裂缝最大估算高度直接影响地表浅部的2煤层和3煤层时,应根据理论分析和实地观测的方法进行沉降预测,适时提供有效的安全预警信息;在开采垂直裂缝最大估算高度不影响地表的深部煤层时,可根据实际观测的历史数据建立灰色Logistic I/II模型进行地面沉降预测,无须再进行实际监测。通过实践验证和模型精度检验表明,灰色Logistic I/II模型预测精度高,预测值与实际值拟合度高,能准确提供有效信息,为地表环境的复垦规划提供重要参考依据。
After the exploitation of underground coal resources,the cracking,subsidence,deformation and other geological disasters may occur in the surface because of the instability of overlying strata,the collapse and the re-compacting.The traditional methods to deal with coal mine subsidence include geological methods,field monitoring,physical and numerical simulations and others,but they are often costly and time consuming,and some parameters are very difficult to identify.In order to obtain accurate information about the ground subsidence in coal mining,the mining-induced stress-relief principle and the "three-zone" model are applied in this paper,and the coal mining subsidence in Tuzhu Coal Mine of Jinzhushan Mining Company is studied.The occurrence mechanism and characteristics of surface cracks and settlement in underground coal mining are analyzed.It is suggested that:(1) when exploiting the shallow coal seams with a large estimate of vertical cracks which would directly affect the surface,one should make settlement prediction on the basis of theoretical analysis and field observation methods,to obtain timely effective security warning information;(2) when exploiting the deep coal seams with a large estimate of vertical cracks which do not affect the surface,one should,on the basis of the actual observation data,establish gray Logistic I/II models to predict the land subsidence,and without the need to carry out the practical monitoring.Practical verification and model accuracy test show that the Grey Logistic I/II models can make accurate predictions,with a good agreement between the predictive value and actual value.It can provide effective and accurate information,and also can provide an important reference for the reclamation planning of surface environment.