多因素复合分析法对直罗组砂岩富水性研究
Study on multi-factor complex analysis method applied to watery of sandstone in Zhiluo Formation
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摘要: 针对陕北侏罗系煤田顶板直罗组砂岩水害难以防治的问题,以柠条塔井田顶板突水为例,分析了砂岩含水层厚度、砂泥岩组合及风化砂岩层3个因素对直罗组砂岩含水层富水性的影响程度;基于多因素复合分析法,确定了直罗组岩性结构指数、砂泥比系数、砂岩风化率3个指标对砂岩含水层富水性的权重及直罗组砂岩富水性等级范围划分。研究结果表明,岩性结构指数能很好地反映砂岩含水层的孔隙度、渗透性及粒度对富水性的影响;应用多因素复合分析方法确定了3个影响因素的权重系数分别为0.3、0.3、0.4,并根据权重结果将其富水性分区划分为强、中、弱3个等级,其中综合指数为0~1.6为弱富水区、1.6~2.3为中等富水区、2.3~3.0为强富水区,强富水性区域主要位于井田南部、中西部及东北部的局部,富水性中等的区域主要分布于井田中部及北部的大部分区域,井田的南北翼各存在一个相对较弱的富水区。分区预测结果与矿井实际顶板突水区域具有较好的一致性,为陕北侏罗系煤田顶板水害防治提供了一种有效预测途径。Abstract: According to the water disaster prevention and control problems of the sandstone roof in Zhiluo Formatior of Shaanbei Jurassic Coalfield,based on the roof water inrush occurred in Ningtiaota Minefield as a case,the paper analyzed thee factors of th aquirerthckress of the sandstone.the sand-nud sone compostinand the weathered sandstone affected to the watery of the sandstone aquifer in Zhiluo Formation.Baed on the muiti acor complex analysis method,he ltnology stuc:ure index of Zhiluo Formation,the sand and mudration coefcient and sandstone weathering rate were detemined tothe watery weighting of the acufe in the sandstone and the watery grade valuation scope of the sandstone in Zhluo Formation.The studlyresultshowed that th ltholgy structure indexcoud wel efet the porositypermeability and partcle size of the aquifer n the sandstone affected to the watery.The muti factor complex analysis method was appied todeemine that the weightingcoeficient of the threeinfuence factors were 0.3,0.3 and 0.4 indidualla.According to the weighting resuli the watery zone could be dided to three grades of strongmedum and weak. Among them O ~ 1.6 would be a weak water zone,1.6 ~ 2.3 would be a medium watery zone and 2.3 ~ 3. woul be a trong wvalery zone.The srong water region would be mainly located in the south part and the centralwvest part of the minefeld and some part of the north-east par.The watey medunregion woud be mainlylcated in the central part of the minefeld and the majof region of the norh part n the south and north wings of the mine fel , there would be a relative weak watery zone indidually.The dided zone predicted results and the mine actual oof water inush region would have a good cons istency and could provide an ef.cie prediction access to prevent and control the roof water disasters occurred in the North Shaanxi Jurassic Coalfield.