地下采煤引起的黄土裂隙化物理模型试验研究

Experimental Study on Physical Model of Loess Fissure Caused by Underground Coal Mining

煤矿采空区的黄土边坡裂隙化严重,为研究地下采煤对黄土边坡裂隙化的影响,通过分级撤去缩尺模型底部支撑力来模拟开采过程,利用布里渊光纤应变测试仪监测各阶段中坡体的应变,结合其位移变化,分析黄土斜坡在地下采空条件下裂隙产生的位置、形态、斜坡体内部应力变化及黄土斜坡裂隙化规律。结果表明:地下采煤不仅导致黄土斜坡产生剪切裂缝还会产生拉张裂缝,产生裂缝的类型与采空塌陷的位置有关;地下采煤导致黄土斜坡产生的裂缝将切割斜坡,被切割的块体临空面较原始斜坡变陡,坡内应力状态发生变化,同时坡体完整性变差,天然强度降低;裂隙分布规律与采空塌陷边界基本一致;地下采煤引起的黄土裂隙化会改变坡体内应力重分布,重分布应力会产生次级裂缝,进一步破坏坡体。

Complicated activities in rural areas have resulted in a large difference in rural water supply between predicted and actual amounts.To address this issue,by using fuzzy C-cluster analysis and Elman neural network model,a prediction model of rural water demand was established.First,statistics of water consumption from 2010 to 2017 in 16 villages in Baoting County,Hainan,South China were selected,and classified into three categories.Second,all available information of published or unpublished,and official or non-official materials were studied,from which we determined key factors and carried out dimension reduction on them with SPSS software.Finally,the key factors and water consumption data from 2010 to 2016 were input into Elman neural network algorithm to validate and tune the model in the rough set theory.After error analysis,the mean absolute percentage error(MAPE)decreased from 0.27 to 0.127,SMAP decreased from 0.082 to 0.041,mean absolute error(MAE)decreased from 3832.32 to 1325.53,indicating that the model could comprehensively simulate the variation rule of rural water demand,be used for accurate prediction of rural water resources,and provide theoretical basis for integration of urban and rural water supply.