排序方式： 共有52条查询结果，搜索用时 15 毫秒
11.
通过对崔庄煤矿矿井水文地质条件分析认为，该矿井属于以静储量为主，以孔隙含水层充水特征的简单类型。预计矿井正常涌水量-250m水平为131．95m^3／h，一400m水平为162．02m^3／h；最大涌水量为324m^3／h。 相似文献
12.
Impact of karst water on coal mining in North China 总被引：1，自引：0，他引：1
Coalfields in North China encompass more than ten Provinces. They contain six to seven coal seams in the Permo-Carboniferous
strata. The lower three seams account for 37% of the total reserves and are threatened with intrusion of karst water from
the underlying Ordovician limestone. Hundreds of water inrush incidences have occurred, in which a large amount of water suddenly
flows into tunnels or working faces under high potentiometric pressure. Over 50 mines have been flooded over the last 30 years.
Large-scale dewatering or depressurizing of the karst aquifer was considered essential to avoid water inrushes and keep the
mines safely operational. This practice, however, has caused sinkholes, dry springs, water supply shortage, and groundwater
contamination in the surrounding areas. One alternative water control measure is to make full use of the rock layer between
the coal seam and the karst aquifer as a protective barrier to prevent or constrain water flow from the underlying aquifer
into the mines. Grouting is effective when the hydrogeological conditions are favorable to this technique. Proper design of
the grouting program and experience of the contractor are also important for a successful application. 相似文献
13.
14.
The southern Chilean convergent margin, between 50° and 57° S, is shaped by the interaction of the three main plates: Antarctic, South America and Scotia. North of 53° S, the convergence between Antarctic and South America plates is close to orthogonal to the continental margin strike. Here, the deformational style of the accretionary prism is mainly characterized by seaward-verging thrusts and locally by normal faults and fractures, a very limited lateral extension of prism, a very shallow dip ( 6°) décollement, and subduction of a thick and relatively undeformed trench sedimentary sequence. South of 53° S, convergence is oblique to the margin, locally, the trench sediments are proto-deformed by double vergence thrusting and the front of the prism grows through landward-verging thrusting. The décollement is sub-horizontal and deep, involving most of the sediment over the oceanic crust in the accretionary process, building a comparatively wide and thicker prism. A Bottom Simulating Reflector is present across the whole prism to the abyssal plan, suggesting the presence of gas in the sediments.The analysis of P- and S-wave velocity reflectivity sections, derived by amplitude versus offset technique (AVO), detailed velocity information and the velocity-derived sediment porosity have been integrated with the structural analysis of the accretionary prism of two selected pre-stack depth migrated seismic lines, aiming to explain the relation between fluid circulation and tectonics.Accretion along double vergence thrust faults may be associated with the presence of overpressured fluid, which decreases the effective shear stress coefficient along the main décollement and within the sediments, and modify the rheolgical properties of rocks. The presence of an adequate drainage network, represented by interconnected faults and fractures affecting the entire sedimentary sequence, can favour the escape of pore fluid toward the sea bottom, while, less permeable and not faulted sediments can favour fluid accumulations. Gravitational and tectonic dewatering, and stratigraphy could control the consolidation and the pore overpressure of sediments involved in subduction along the trench. The results of our analysis suggest the existence of a feedback between tectonic style and fluid circulation. 相似文献
15.
16.
Josephine Lim Ross G. de Kretser Peter J. Scales 《International Journal of Mineral Processing》2009,93(2):15-102
The influence of clay dispersion method on dewatering behaviour of a run-of-mine bentonite was examined to better understand the roles of calcium–sodium ion exchange and overall electrolyte concentration on the suppression of swelling and subsequent stabilisation of the clay. As with previous work, controlled dispersion of the clay directly into a swelling suppressing environment was observed to yield order of magnitude improvements in dewatering behaviour [de Kretser, R.G., Scales, P.J. and Boger, D.V., 1997. Improving clay-based tailings disposal: a case study on coal tailings. AIChE Journal. 43 (7), 1894–1903.]. The calcium ion, even after normalisation for its valence, yielded significantly better clay stabilisation performance than the sodium ion indicating the greater benefit afforded via divalent ion-exchange driven controlled dispersion. However the results also highlighted a synergistic effect of the double layer suppression effect on the efficacy of ion-exchange mediated controlled dispersion through simultaneous swelling suppression and structure preservation during the transient process of ion exchange on hydration. Studies of controlled dispersion in dual ion, Na+ and Ca2+, systems illustrated that although the efficacy of controlled dispersion deteriorated with an increase in the Na+ to Ca2+ ratio, even small amounts of calcium character could generate significant improvements in dewaterability over the pure sodium case. This result was relevant in terms of defining an operational window for the commonly used, but sparingly soluble calcium source, gypsum where the low deliverable calcium level could be more than offset by the controlled dispersion benefits of maintaining a higher overall salinity level. Based on the results presented, the potential impact of practical implementation of a controlled dispersion framework within a mineral processing operation was illustrated via numerical modelling of the operation of a steady state thickener. 相似文献
17.
对山西4口水化学观测井（泉）及周边地表水进行水化学和氢氧同位素分析,利用Piper图、durov图、Na-K-Mg三角图等方法研究其水化学特征及成因,得出井（泉）水岩平衡程度、热储温度、地下水循环深度及地下水补给来源详情;分析了井（泉）水氡测项映震特征,应用水氡映震效果与水岩平衡程度、地下水循环深度表现出的特征,评价了地震监测效能。评价结果显示夏县井、奇村井优于临猗井,适于开展地震水化学观测;定襄泉应用该水化学方法评价尚存不足之处,需要探索适用于该类观测泉点的物理与化学相结合的评价方法。 相似文献
18.
Wells turbine with end plates for wave energy conversion 总被引：1，自引：0，他引：1
Manabu Takao Toshiaki Setoguchi Yoichi Kinoue Kenji Kaneko 《Ocean Engineering》2007,34(11-12):1790-1795
In order to improve the performance of the Wells turbine for wave energy conversion, the effect of end plate on the turbine characteristics has been investigated experimentally by model testing. As a result, it is found that the characteristics of the Wells turbine with end plates are superior to those of the original Wells turbine, i.e., the turbine without end plate and the characteristics are dependent on the size and position of end plate. Furthermore, by using a computational fluid dynamics (CFD), reason of the performance improvement of the turbine has been clarified and the effectiveness of the end plate has been demonstrated. 相似文献
19.
With an additional vertical duct at the wave-beaten side, an OWC is expected to give some much better performances. This is, essentially, due to two reasons. First, an OWC with the additional vertical duct (U-OWC) has an eigenperiod greater than the eigenperiod of a conventional OWC. Second, the amplitude of the pressure fluctuations on the opening of a U-OWC is greater than the amplitude of the pressure fluctuations on the opening of a conventional OWC (the greater the smaller the wave period is). For the first reason, a U-OWC can give performances better than those of a conventional OWC both with swells and large wind waves. For the second reason, a U-OWC can give performances better than those of a conventional OWC also with small wind waves. 相似文献
20.
Current‐aligned dewatering sheets and ‘enhanced’ primary current lineation in turbidite sandstones of the Marnoso‐arenacea Formation 
下载免费PDF全文
下载免费PDF全文 Lawrence A. Amy Peter J. Talling Esther J. Sumner Giuseppe Malgesini 《Sedimentology》2016,63(5):1260-1279
Turbidite sandstones of the Miocene Marnoso‐arenacea Formation (northern Apennines, Italy) display centimetre to decimetre long, straight to gently curved, 0·5 to 2·0 cm regularly spaced lineations on depositional (stratification) planes. Sometimes these lineations are the planform expression of sheet structures seen as millimetre to centimetre long vertical ‘pillars’ in profile. Both occur in the middle and upper parts of medium‐grained and fine‐grained sandstone beds composed of crude to well‐defined stratified facies (including corrugated, hummocky‐like, convolute, dish‐structured and dune stratification) and are aligned sub‐parallel to palaeoflow direction as determined from sole marks often in the same beds. Outcrops lack a tectonic‐related fabric and therefore these structures may be confidently interpreted to be sedimentary in origin. Lineations resemble primary current lineations formed by the action of turbulence during bedload transport under upper stage plane bed conditions. However, they typically display a larger spacing and micro‐topography compared to classic primary current lineations and are not associated with planar‐parallel, finely laminated sandstones. This type of ‘enhanced lineation’ is interpreted to develop by the same process as primary current lineations, but under relatively high near‐bed sediment concentrations and suspended load fallout rates, as supported by laboratory experiments and host facies characteristics. Sheets are interpreted to be dewatering structures and their alignment to palaeoflow (only noted in several other outcrops previously) inferred to be a function of vertical water‐escape following the primary depositional grain fabric. For the Marnoso‐arenacea beds, sheet orientation may be linked genetically to the enhanced primary current lineation structures. Current‐aligned lineation and sheet structures can be used as palaeoflow indicators, although the directional significance of sheets needs to be independently confirmed. These indicators also aid the interpretation of dewatered sandstones, suggesting sedimentation under a traction‐dominated depositional flow – with a discrete interface between the aggrading deposit and the flow – as opposed to under higher concentration grain or hindered‐settling dominated regimes. 相似文献