Characteristics of sand damages and dynamic environment along the Tuotuohe section of the Qinghai-Tibet Railway     

KeCun Zhang  QingHe Niu  JianJun Qu  ZhengYi Yao  QingJie Han 《寒旱区科学》2011,3(2):0137-0142

Sand damages along the Qinghai-Tibet Railway occur frequently and have spread rapidly since it was completely opened to traffic in 2006. The goal of this study was to understand the effects of sand damages on the railway via meteorological data and in situ observation of wind-blown sand. We selected the Tuotuohe section of this railway as a typical research object, and we systematically investigated its characteristics of sand damages, drift potential, sand-driving wind rose, and their time variation. The direction of sand-drifting wind clearly varies with the season. In winter, the predominant wind blows from the west and lasts for three months, while in summer the frequency of northeasterly wind begins to increase and multi-directional winds also occurs in July. The drift potential in this area is 705.81 VU, which makes this a high-energy wind environment according to Fryberger’s definition. The directional variability (RDP/DP) is 0.84 and the resultant drift potential is 590.42 VU with a resultant direction of 89.1°.  相似文献   

一种桩锚连接的新方法——双向支座法     

韩凤霞  田树玉  杨晓鹏 《岩土工程技术》2015,(1):46-50

阐述一种新型的在基坑及边坡支护工程中的传力装置——双向支座法,详细论述了目前普遍使用的腰梁工法的不足,并对其进行了改进,提出了新的施工方法,在基坑支护工程中具有较高的推广和实用价值。  相似文献   

多孔黏弹介质平面波理论及波场数值模拟     

高晗  韩立国  凌云  张盼  宋超  孙慧秋 《世界地质》2015,34(4):1098-1105

本文将黏弹固体骨架与各向异性多孔弹性模型相结合,并将地层黏弹性的特性考虑其中,更好地刻画了快P波和横波在地震频带的衰减现象。将多孔黏弹模型模拟结果同传统弹性模型模拟结果对比显示,多孔黏弹模型在模拟真实储层方面更具优势。  相似文献   

对甘肃宕昌县代家庄铅锌矿床成因的认识          下载免费PDF全文

张晓明  刘懿伟  李延涛  祁晗 《甘肃地质》2015,24(3):31-35

甘肃省宕昌县代家庄铅锌矿床的发现是近年来西秦岭地区铅锌找矿的重大进展。其类型为以菱锌矿、白铅矿为主的碳酸盐型铅锌矿,成为西成矿田西延地段发现新的成矿类型。区内圈定铅锌矿体6条,产于泥盆系龙鳞桥组第2岩性段与第3岩性段的过渡带和东沟组中,受NW—SE向压扭性断裂破碎带控制。断裂是成矿最主要的控制因素,不仅控制着铅锌多金属矿体的沉积就位,而且在成矿后期对矿体的改造起主导作用。矿区内未见岩浆岩及典型的热液蚀变现象。文章分析了成矿地质背景和矿床地质特征,铅同位素显示变化范围小,说明铅来源比较单一,硫同位素结果说明硫质来源于沉积地层中。闪锌矿中流体包裹体均一温度分别为80℃~120℃和120℃~160℃,说明成矿温度总体比较低。初步认为其成因沉积改造型铅锌矿床。  相似文献   

An extensive erosion surface of a strongly deformed limestone bed in the Gushan and Chaomidian formations (late Middle Cambrian to Furongian), Shandong Province,China: Sequence–stratigraphic implications     

Jitao Chen  S.K. Chough  Zuozhen Han  Jeong-Hyun Lee 《Sedimentary Geology》2011,233(1-4):129-149

In order to understand sequence development and sea-level fluctuations during the late Middle Cambrian to early Furongian on the North China epeiric platform, the present study focuses on a unique, subtle erosion surface of an extensive (approx. 100 km), strongly deformed limestone bed in the uppermost part of the Gushan Formation, Shandong Province, China. The Gushan Formation and the overlying Chaomidian Formation consist mainly of shales and a variety of carbonates that were deposited in subtidal environments (e.g., deep subtidal, shallow subtidal, shoreface/shoal, subtidal microbial flat, and restricted platform interior). Three third-order depositional sequences (S1–3) are identified, each of which comprises a thin transgressive systems tract (TST) and a relatively thick highstand systems tract (HST). Each sequence is bounded by a drowning unconformity (SB1), a subaerial unconformity (SB2), or a surface of submarine erosion (SB3). The upper sequence boundary (SB2) of sequence 1 (S1) is represented by a subtle erosion surface of an extensive, deformed limestone bed with a wide variety of soft-sediment deformation structures (e.g., lime mudstone breccias, chaotic wacke-packstone laminae and fragments, homogenized oolites, and clastic dykes), and is overlain by small sporadic microbial buildups and an extensive bioclastic grainstone bed. The deformed limestone was formed during early diagenesis by differential deformation processes (brecciation, liquefaction/fluidization, and injection) which were most likely induced by pore-water overpressure during the period of rapid sea-level fall. Despite the lack of subaerial exposure features (e.g., paleokarst, paleosol, etc.), the characteristics of the erosion surface (cutting well-lithified sediment below), the missing of a significant geological record (the Prochuangia biozone), and the worldwide correlatable positive carbon isotope excursion collectively indicate that the erosion surface developed under conditions of subaerial exposure after contemporaneous marine cementation of the deformed sediment. The missing of the Prochuangia biozone is most likely due to non-deposition at a subaerial hiatal surface. The erosion surface was submerged as a result of subsequent rise in sea level, where sporadic microbial buildups formed under suitable conditions. Freshly deposited, winnowed, shell-dominated transgressive lag deposits (containing Chuangia trilobite fragments, brachiopod shells, and abundant glauconite grains) formed with continued rise in sea level, which became, in turn, overlain by shale-dominated facies. The unique combination of the subtle erosion surface (sensu stricto a subaerial unconformity) and the underlying deformed limestone bed provides an important criterion for recognizing the subtle changes in relative sea level on shallow epeiric platforms.  相似文献   

海塔盆地优质储层发育特征及控制因素分析   总被引：2，自引：2，他引：0       下载免费PDF全文

张云峰  徐涵  肖岩岩  张玉鹏 《地质科学》2011,46(4):1017-1024

凝灰质砂岩是海塔盆地主要油气储集岩层,凝灰质含量随地层变老而增多,储层物性非均质性强,大量薄片等储层微观分析结果表明,凝灰质砂岩成分和结构成熟度较低,储层储集空间主要为溶蚀成因的次生孔隙,且次生孔隙比例随地层变老而增加.本文提出孔隙成因法,并根据该方法确定凝灰质砂岩优质储层物性下限的孔隙度为10％,渗透率为0.1×10...  相似文献   

Major element chemistry of the Huai River basin, China   总被引：3，自引：0，他引：3  

Liang Zhang  Xianfang Song  Jun XiaRuiqiang Yuan  Yongyong ZhangXin Liu  Dongmei Han 《Applied Geochemistry》2011,26(3):293-300

The chemistry of major ions (Ca, Mg, Na, K, HCO₃, SO₄, Cl and Si) in the water of the Huai River basin was studied, based on samples from 52 sites from nine different water bodies in July 2008. Ions and total dissolved solids (TDS) displayed clear spatial patterns with lower concentrations in the south and higher in the north of the basin; the same conditions were also found in the East Line of South-North Water Transfer Project (SNWTP) in this region. The Huai River main channel and Hongze Lake have moderate ion concentrations relative to the whole basin. TDS concentrations versus the weight ratios of Na/(Na + Ca) and ternary ions demonstrate that the southern rivers (Shi R. and Pi R.) are mainly controlled by the weathering of carbonates, whereas the northern water systems (Guo R., Shaying R., Nansi Lake and its tributaries) are dominated by the weathering of evaporites. The Huai River main channel, Hongze Lake and the East Line of SNWTP are synergistically influenced by weathering of evaporites and carbonates, yet Hongze Lake and the East Line of SNWTP are mainly controlled by evaporation and crystallization processes. This study also confirmed that the Huai River is the geographic division between southern and northern China. Most rivers of this basin have very high ionic composition relative to the global median and other world rivers. The spatial patterns and ionic composition also suggest that intensive anthropogenic activities in northern areas of this basin are well characterized. A comparison with WHO and Chinese standards for drinking water indicates that the northern water systems of this basin are not suitable for use as drinking water sources, and pollution control should be improved and enhanced in northern areas of the basin.  相似文献   

The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards   总被引：19，自引：5，他引：14  

Peng Cui  Xiao-Qing Chen  Ying-Yan Zhu  Feng-Huan Su  Fang-Qiang Wei  Yong-Shun Han  Hong-Jiang Liu  Jian-Qi Zhuang 《Natural Hazards》2011,56(1):19-36

On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province, China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”), and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches, 515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example, debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards, particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas is needed in advance.  相似文献   

Long-term simulations of the sulfur concentrations over the China, Japan and Korea: A model comparison study     

Cheol-Hee Kim  Lim-Seok Chang  Jeong-Soo Kim  Fan Meng  Mizuo Kajino  Hiromasa Ueda  Yuanhang Zhang  Hye-Young Son  Youjiang He  Jun Xu  Keiichi Sato  Chang-Keun Song  Soo-Jin Ban  Tatsuya Sakurai  Zhiwei Han  Lei Duan  Suk-Jo Lee  Shang-Gyoo Shim  Young Sunwoo  Tae-Young Lee 《Asia-Pacific Journal of Atmospheric Sciences》2011,47(4):399-411

Three comprehensive acid deposition models were used to simulate the sulfur concentrations over northeast Asia over the period covering entire year of 2002, and discussed the aggregated uncertainties and discrepancies of the three models. The participating models are from the countries participating in the project of Longrange Transboundary Air Pollutants in Northeast Asia (LTP): China, Japan and Korea. The Eulerian Model-3/CMAQ (by China), Regional Air Quality Model (RAQM, by Japan), and Comprehensive Acid Deposition Model (CADM, by Korea) were employed by each country with common emissions data established by the administrative agencies of China, Japan and Korea. The episodic simulation results between 1 to 15, March 2002 are also presented, during which aircraft measurements were carried out over the Yellow sea. The episodic results show both a wide short-term variability in simulations against measurements, and maximum concentration differences of 3～5 times among the three models, requiring that further attention before confidence among the three models can be claimed for short-term simulations. However, the year-long cumulative simulations showed almost the same general features, with lower aggregated uncertainties between the three models, produced by the long term integration over northeast Asia.  相似文献   

VTI介质中准P波方程叠前逆时深度偏移   总被引：3，自引：0，他引：3       下载免费PDF全文

韩令贺  何兵寿  张会星 《地震学报》2011,33(2):209-218

根据具有垂直对称轴的横向各向同性（VTI）介质中的一阶准P波方程,导出了该方程在交错网格中逆时延拓的高阶有限差分格式,给出了其稳定性条件,采用完全匹配层吸收边界条件解决边界反射问题,分别应用下行波最大能量法和归一化互相关成像条件, 实现了VTI介质中准P波方程的叠前逆时深度偏移．各向异性Marmousi模型的试算结果表明,VTI介质准P波方程叠前逆时深度偏移算法不受地下构造倾角和介质横向速度变化的限制,对复杂模型具有良好的成像能力;应用归一化互相关成像条件能得到更好的成像效果．对比该模型的各向异性和各向同性逆时偏移剖面表明,在各向异性地区采集的纵波数据用各向异性偏移算法理论上能得到更好的成像结果．   相似文献