为准确合理地评价煤层顶板突水危险性,文章基于地理信息系统(geographic information system,GIS)空间分析技术,结合熵权法对突水分区变权模型进行改进优化。为避免权重确定的主观性与计算复杂性,引入信息熵求取常权向量。为防止“极大...为准确合理地评价煤层顶板突水危险性,文章基于地理信息系统(geographic information system,GIS)空间分析技术,结合熵权法对突水分区变权模型进行改进优化。为避免权重确定的主观性与计算复杂性,引入信息熵求取常权向量。为防止“极大”或“极小”值权重超调过大,提高各主控因素综合控制作用与各分区值变权重均衡性,采用保守型分区变权函数对变权模型进行修正。通过直接对主控因素栅格图运算和处理,避免因钻孔插值所造成的构造信息丢失问题。将改进模型与常权模型及仅通过钻孔构建的风险型分区变权模型进行比较,以实际突水点对评价模型进行识别检验。结果表明,改进的分区变权模型评价效果更好、精度更高,对煤矿顶板水害预测与防治具有指导性作用,在口孜东矿取得良好的应用效果。展开更多
为进一步认识淮南煤田阜凤逆冲推覆构造带中段构造变形机制及对煤层气赋存的控制,指导下一步煤层气勘探开发,利用最新的煤田地质勘探与开发资料,通过详细的构造解析与对比,结合区域地质背景,分析了新集和罗连井田差异性逆冲推覆构造变...为进一步认识淮南煤田阜凤逆冲推覆构造带中段构造变形机制及对煤层气赋存的控制,指导下一步煤层气勘探开发,利用最新的煤田地质勘探与开发资料,通过详细的构造解析与对比,结合区域地质背景,分析了新集和罗连井田差异性逆冲推覆构造变形特征及其形成演化机制。利用Thermodel for Windows软件对新集与罗连井田含煤地层构造埋藏-热演化史进行了恢复模拟,揭示了构造变形对煤层气生成与分布的控制规律。结果表明:在印支期自南向北的推挤作用下,罗连井田表现为叠瓦扇状构造变形的特点,下伏原地系统构造变形较弱;新集井田受煤系基底隆起阻挡,表现为双重逆冲推覆构造变形的特点,原地系统在纵弯褶皱变形中沿褶曲轴部形成了大量伸展性构造。新集与罗连井田含煤地层均经历了4个阶段的构造埋藏史与热演化史过程,但新集井田煤层变质程度与生气量明显偏高;煤系基底隆起与构造变形结构空间耦合引起的古地温梯度变化,是控制新集与罗连井田煤层气差异生成、富集的根本原因;新集与罗连井田现今煤层含气量空间分布与构造位置相关性明显,主要受构造变形程度与埋深影响。展开更多
Three dimensional wave-induced mixing plays an important role in shallow water area. A quite direct approach through the Reynolds average upon characteristic length scale is proposed to parameterize the horizontal and...Three dimensional wave-induced mixing plays an important role in shallow water area. A quite direct approach through the Reynolds average upon characteristic length scale is proposed to parameterize the horizontal and vertical shallow water mixing. Comparison of finite depth case with infinite depth results indicates that the difference of the wave-induced mixing strength is evident. In the shallow water condition, the infinite water depth approximation overestimates the mixing strength in the lower layers. The nonzero horizontal wave-induced mixing presents anisotropic property near the shore. The Prandtl's mixing length theory underestimated the wave-induced mixing in the previous studies.展开更多
文摘为准确合理地评价煤层顶板突水危险性,文章基于地理信息系统(geographic information system,GIS)空间分析技术,结合熵权法对突水分区变权模型进行改进优化。为避免权重确定的主观性与计算复杂性,引入信息熵求取常权向量。为防止“极大”或“极小”值权重超调过大,提高各主控因素综合控制作用与各分区值变权重均衡性,采用保守型分区变权函数对变权模型进行修正。通过直接对主控因素栅格图运算和处理,避免因钻孔插值所造成的构造信息丢失问题。将改进模型与常权模型及仅通过钻孔构建的风险型分区变权模型进行比较,以实际突水点对评价模型进行识别检验。结果表明,改进的分区变权模型评价效果更好、精度更高,对煤矿顶板水害预测与防治具有指导性作用,在口孜东矿取得良好的应用效果。
文摘为进一步认识淮南煤田阜凤逆冲推覆构造带中段构造变形机制及对煤层气赋存的控制,指导下一步煤层气勘探开发,利用最新的煤田地质勘探与开发资料,通过详细的构造解析与对比,结合区域地质背景,分析了新集和罗连井田差异性逆冲推覆构造变形特征及其形成演化机制。利用Thermodel for Windows软件对新集与罗连井田含煤地层构造埋藏-热演化史进行了恢复模拟,揭示了构造变形对煤层气生成与分布的控制规律。结果表明:在印支期自南向北的推挤作用下,罗连井田表现为叠瓦扇状构造变形的特点,下伏原地系统构造变形较弱;新集井田受煤系基底隆起阻挡,表现为双重逆冲推覆构造变形的特点,原地系统在纵弯褶皱变形中沿褶曲轴部形成了大量伸展性构造。新集与罗连井田含煤地层均经历了4个阶段的构造埋藏史与热演化史过程,但新集井田煤层变质程度与生气量明显偏高;煤系基底隆起与构造变形结构空间耦合引起的古地温梯度变化,是控制新集与罗连井田煤层气差异生成、富集的根本原因;新集与罗连井田现今煤层含气量空间分布与构造位置相关性明显,主要受构造变形程度与埋深影响。
基金supported by the national young scientist fund of China under contract under contract No 40206003special fund for fundamental scientific research under contract (No 2007G15)
文摘Three dimensional wave-induced mixing plays an important role in shallow water area. A quite direct approach through the Reynolds average upon characteristic length scale is proposed to parameterize the horizontal and vertical shallow water mixing. Comparison of finite depth case with infinite depth results indicates that the difference of the wave-induced mixing strength is evident. In the shallow water condition, the infinite water depth approximation overestimates the mixing strength in the lower layers. The nonzero horizontal wave-induced mixing presents anisotropic property near the shore. The Prandtl's mixing length theory underestimated the wave-induced mixing in the previous studies.