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1.
渭北煤田面积约10万km2。分布于太原组顶部5#煤层中的粘土岩夹矸,上部层位分为两上分层,上分层夹矸厚度薄,下分层夹矸厚约02m,俗称“200矸”;下部层位夹矸厚度变化较大。该文详细论述了粘土岩夹矸的岩矿特征。根据“200矸”中含有副象β-石英、高透长石、锆石、磁铁矿等高温矿物组合,特有的粒序层理和岩性在全煤田十分稳定等特点,表明其原始物质来源于降落火山灰。根据TiO2/Al2O3比值的明显变化,探讨了陆源组分的加入对火山灰蚀变粘土岩夹矸化学成分的影响。以“200矸”为等时标志层,解决了5#煤层在区域上的对比。 相似文献
2.
Numerical simulations for coupled rock deformation and gas leak flow in parallel coal seams 总被引:3,自引:0,他引:3
Peide Sun> 《Geotechnical and Geological Engineering》2004,22(1):1-17
Based on the new viewpoint of interaction mechanics for solid and gas, gas leakage in parallel deformable coal seams can be
understood. That is, under the action of varied geophysical fields, the methane gas flow in a double deformable coal seam
can be essentially considered to be compressible with time-dependent and mixed permeation and diffusion through a pore-cleat
deformable, heterogeneous and anisotropic medium. From this new viewpoint, coupled mathematical models for coal seam deformation
and gas leak flow in parallel coal seams were formulated and the numerical simulations for slow gas emission from the parallel
coal seams are presented. It is found that coupled models might be close to reality. Meanwhile, a coupled model for solid
deformation and gas leak flow can be applied to the problems of gas leak flow including mining engineering, gas drainage engineering
and mining safety engineering in particular the prediction of the safe range using protective layer mining where coal and
gas outbursts can efficiently be prevented.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
ZHAO Honggang LI Ying CHANG Xiangchun LI Zengxue LIU Haiyan ZHAO Cunliang 《《地质学报》英文版》2021,95(1):121-130
The coal-forming characteristics,as well as the similarities and differences between epicontinental sea basins and continental marginal sea basins developed during different time periods,were analyzed in this study by adopting comparative analysis thoughts and methods.The results obtained in this study revealed that epicontinental basins and marginal sea basins are both characterized by the main development of thin coal seams or extremely thin coal seams.In addition,changes in sea levels were determined to be the main controlling factors for coal formation,and there were similarities in the continent-sea interactions and coal-forming sedimentary systems of the different basins.However,there were also significant differences observed in the sea level change events,basin basement structural characteristics,coal seam stability levels,accumulation and aggregation characteristics,and the migration patterns of coal-forming materials.For example,the marginal sea basins in the South China Sea were found to be characterized by strong tectonic activities,diversity and complexity.The basin structures showed complex patterns of depressions,uplifts and concave or sag uplifts,which tended to lead to greater complexity in the paleogeographic patterns of the coal formations.This had subsequently resulted in complex coal-forming processes and paleogeographic characteristics,in which the coal-forming zones displayed bead-like distributions,and the enrichment areas and centers were scattered.The practical significance of studying the similarities and differences of the coal-forming characteristics between epicontinental basins and marginal sea basins is that the results can potentially be used to guide the predictions of coal-measure coal seam distributions in South China Sea,as well as provide valuable guidance for future explorations of natural gas reservoirs related to coal measures in the South China Sea area. 相似文献
4.
贵州兴达井田含煤9-17层,其中K1、K2、K3、K4四层煤较稳定,为主要可采煤层。依据钻孔资料,分析测井曲线形态与煤层顶底板以及上下标志层间的组合关系,对井田的煤岩层进行了对比。该井田K1煤层常分叉为K1上、K1下两个分层,其直接顶板高视电阻率异常,三叠系至K1煤层组间自上而下的缓坡状视电阻率曲线形态与自然伽马幅值相对较高的组合特征可作为二叠系含煤地层与三叠系地层划分依据;K2煤层位于龙潭组顶部,下距长兴组灰岩标志层10m左右,煤层本身高伽马异常;K3、K4煤层及其底板具较高的自然伽马特征。 相似文献
5.
辽宁省大石桥-吉洞峪一带出露的主要为古元古代的变质层状岩系,由云母片岩、长英质粒岩和大理类组成。区域上形成一大型北东向的复式向斜构造。复向斜南北两翼变质地层对比问题是辽吉东部辽河岩群研究的主要内容之一。作者根据五年来在大石桥-吉洞峪一带进行1∶5万区调所获得的新资料,从标志层及组合标志层、岩相学特征、主要标志层的岩石化学和稀土地球化学特征、变质作用演化等方面的研究入手,讨论了复向斜两翼变质地层对比的问题。结果表明,辽河岩群构成复向斜南北两翼的变质地层是完全可以对比的,从而进一步证实辽河岩群是一个不可分割的整体 相似文献
6.
N. S. Krishnamurthy V. Ananda Rao Dewashish Kumar K. K. K. Singh Shakeel Ahmed 《Journal of the Geological Society of India》2009,73(5):639-650
Exploration and exploitation of coal seams is one of the major resources for the energy sector in any country but at the same
time water filled voids/water logged areas in the old workings of these seams are very critical problems for the coal mining
industry. In such situations, disasters like inundation, landslides, collapsing of the old seams may occur. In this regard,
it is necessary to find out the water saturated/water filled voids and zones in the mining areas. Since no established technique
is available to find such zones, an experimental study using Electrical Resistivity Imaging (ERI) has been carried out in
one of the coal mining areas near Dhanbad, to find out the feasibility of finding the barrier thickness and the water logged
area in underground coal mines. The area under study forms part of Jharia coalfield in Dhanbad district, Jharkhand state.
The coal bearing rocks of Barakar Formation of Lower Permian age (Gondwana period) occur in the area under a thin cover (10
m to15 m) of soil and or alluvium. Coal bearing Barakar Formations consist mainly of sandstone of varying grain size, intercalation
of shale and sandstone, grey and carbonaceous-shale and coal seams.
Since the water saturation reduces the resistivity of a formation to a large extent, water filled voids and old coal workings
are expected to have significant resistivity contrast with the surrounding host rock. Hence, ERI technique was applied in
such an environment as this technique uses high-density data acquisition both laterally and vertically by using multiple number
of electrodes. Along with ERI, mise-à-la-masse (also called charged body) technique was also employed at one of the promising
sites to find out the connectivity of water logged areas and also detection of these old workings from the surface measurements
was analyzed. The interpreted 2D resistivity sections have clearly indicated the water bearing zone(s) along the profile which
was well confirmed with the existing water level in the nearby borewells. On the other hand, this technique did not identify
the size of the coal pillar and gallery (air filled voids), which might be due to the small size of the voids (i.e. about
2 m × 2 m) below a depth of 15m and more but have indicated altogether as a high resistive zone ranging from 600–1000 Ohm-m. 相似文献
7.
8.
在对30多个煤岩样品在不同围限压力下测得的孔隙度进行研究的基础上,结合煤层甲烷开采的生产特点,讨论了煤岩孔隙度在围限压力下的变化特征。进而探讨了煤岩地下孔隙度的计算方法和煤岩有效孔隙体积压缩系数的变化特征。 相似文献
9.
随着大型煤系稀有金属矿产的发现,煤中伴生微量元素的研究受到广泛关注,但目前对我国西北地区的煤系地层中稀有元素的研究程度较低。选取新疆东北部的准东煤田为研究区,基于煤样的煤质分析和微量元素数据,研究了煤中镓的分布规律、赋存特征及富集成因。研究表明:(1)准东煤田的中侏罗统煤层中镓明显富集。12个矿区煤中镓平均含量在20.78~47.98 μg/g,大多高于或接近煤中镓的边界品位(30 μg/g)。(2)煤田中镓的分布规律性明显。平面上,盆地周围煤中Ga含量较中部矿区高,特别是东北部和西南部由于分别受克拉美丽山和博格达山物源区的影响,煤中Ga含量异常高,部分区域超过了60 μg/g,而中部矿区(ZD10740、ZD10464、ZD10407和ZD10841)的煤中Ga含量表现为从矿区边缘向中心逐渐富集;垂向上,大部分矿区煤中Ga含量从中侏罗统底部向上降低,而受到早燕山运动影响,靠近博格达山的矿区(ZD10740)表现相反。(3)煤中Ga主要以高岭石为载体,部分Ga也存在煤的有机质组分中。镓主要以细粒物质(胶体或有机络合物形式)搬运到沉积盆地,在潮湿覆水沉积条件下发生聚积。 相似文献
10.
针对目前大跨穿煤隧道的研究热点,以重庆市绕城高速公路环山坪隧道为研究对象,在界定大跨度隧道及分析其围岩稳定性关键影响因素的基础上,结合现场监测和数值模拟对大跨度穿煤隧道围岩结构稳定性进行了分析。结果表明,大跨度隧道各处等效应力集中对扁平率变化敏感程度不同,拱脚最为敏感,拱顶基本不随扁平率的改变而变化。隧道穿越软弱煤层段时,围岩应力重分布受影响明显,拱顶位移随开挖面不断推进急剧增加,且隧道围岩塑形圈不断向拱顶围岩内部发展。尤其当煤层软弱带与隧道顺层相交时,隧道荷载结构偏压效应凸显,偏压荷载随煤层倾角变陡而增大,易造成支护结构失稳破坏,在设计及施工中应特别加以重视。 相似文献