矸石充填采煤覆岩移动的弹性地基梁模型分析

基于弹性基础梁解析方法,考虑顶板岩梁触矸前的下沉,建立了长壁工作面采空区矸石充填顶板岩梁力学模型,推导了岩梁下沉基本微分方程,实验得出矸石地基系数为26～127MN/m3.分析了矸石充填条件下矿压显现规律及影响因素、岩梁下沉与地表下沉的关系,结果表明:工作面煤壁后方10～20m后顶板岩梁下沉就接近最大值,矸石地基系数是影响采空区顶板下沉最重要的因素,煤壁附近充填矸石承受的压力随地基系数变化而变化,减少地表下沉最有效的途径是增加kg值和减小W1值,控制煤层之上直接顶板的下沉是控制地表下沉的关键.在煤厚2.1m、埋深437m的条件下工业试验表明,W1可以减少至12～64mm,实测的地表最大下沉平均值为253mm,与解析法预测的261mm很接近.

An elastic base beam model of overlying strata movement during coal mining with gangue back-filling

A mechanical elastic model of the base beam in a long wall face was constructed using the elastic base beam method.The sinking of the roof rock in the goaf before it touches the waste was modeled by obtaining the basic differential equations for the sinking of the rock.The relationship between the sinking beam and surface subsidence was analyzed by predicting the behavior of the strata.The results showed that sinking of the roof beam is approximately at the maximum after about 10 to 20 meters of working face has been developed.The waste base coefficient was found to be the most important factor affecting roof sinking in the goaf.The pressure on the filling waste changes with the waste base coefficient and the most effective way to reduce surface subsidence is by increasing kg and decreasing W1.It is shown that the control of immediate roof subsidence in the coal seam is the key to controlling surface subsidence.Field experiments showed that W1 could be decreased to about 12 to 64 mm and that the average,maximum surface sink is then 253 mm.This is quite close to the predicted 261 mm sink from the model given a 2.1 meter thick coal seam buried 437 meters deep.