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1.
辽宁浦石河抽水蓄能电站地应力测量研究   总被引:1,自引:0,他引:1  
为了解浦石河抽水蓄能电站枢纽区现今应力状态,采用空心包体应力计在探洞内进行了地应力测量。共布设5个地应力测点,每个测点都进行了多次测量,采用最小二乘法对5个测点测量结果进行分别计算和综合计算。测量结果表明:最大主应力近于水平,方向为N79°W,应力量值为7.1MPa;各测点不同测段测量结果有一定偏差,这主要是由于不同部位岩体构造条件所致,随着测量次数增多,最大主应力优势方向还是比较明显的。最后根据实测结果对电站枢纽区现今应力作用特征进行了分析,并对工程设计提出了建议。   相似文献   

2.
The assessment of seismic hazard at five selected sites in the Sannio-Matese region is based on the computer program SRAMSC. Owing to the extensive historical data base for the output parameter, the MSK intensiy is chosen. The seismicity model is made up of five narrow area seismic sources. Circular or elliptical macroseismic fields are assigned to individual sources. A generalized Kövesligethy equation is used for this purpose as the attenuation relationship. The study reveals similar and a rather high hazard at the sites at Benevento, Boiano, and Melfi, which are located in the zone of highest seismic activity. At the Pomigliano and Lucera sites, the assessed hazard is much lower.  相似文献   

3.
对达来诺尔湖北岸岸边(DL-0)、湖中心(DL-1)和湖南岸(DL-2)3个点的岩心沉积物进行了详细的岩性分析、粒度分析和粒度参数垂向分布序列分析。对沉积环境变化较为敏感的粒度组分的分析发现DL-0与DL-1和DL-2井岩心沉积物敏感粒度组分的峰值有较大差别,其粒度分布范围相差较大,表明湖北岸岸边、湖中心和湖南岸的沉积物来源和沉积环境的时空差异。敏感粒度组分含量随深度变化的初步分析表明,湖北岸岸边(DL-0)和湖中心(DL-1)两个点的沉积环境较为稳定;而位于湖南岸(DL-2)点的沉积环境变化比较大,包含了5个明显的沉积波动旋回,并对达来诺尔湖由北至南进行了沉积地层分析。在达来诺尔湖水下1.5m内主要是粒径0~200μm的颗粒,岩性为粘土、粉砂和砂,以粘土和粉砂为主,随着深度的增加,黏土含量增大,粉砂和砂含量减小。  相似文献   

4.
In this paper, we describe Neolithic/Aeneolithic implements made from high‐pressure metabasites: jadeites and eclogites. As such rocks are unknown in the Western Carpathians mountain system, we presume distant source areas for the described raw material types. We present the morphology, cultural association, and the results of petrographic research (microprobe analyses of rock‐forming minerals) on implements made from these raw materials found at two sites in the Slovak Republic. We propose that the raw materials of these implements crop out hundreds of kilometers from the sites on which they were discovered. © 2005 Wiley Periodicals, Inc.  相似文献   

5.
The present work contributes to the debate of skeletal part use in archaeology to reconstruct hominid economic behaviour during the Pleistocene. It doubles the sample of sites where comparison of long limb bone element quantification is made by using alternative identification techniques based on epiphyses and epiphyses plus shafts. A refined method of long limb element quantification using shafts is discussed and applied to four sites representing different time periods from the end of the Middle Pleistocene to the end of the Upper Pleistocene. It is shown that when long limb elements are properly quantified a hypothesis of early access to carcasses at these sites can be supported. The data thus drawn are also used to compare skeletal part evenness across the time periods represented by the four sites selected. The results indicate low‐cost transport decisions by hominids at these sites. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

6.
三峡水库岸沿岸移民区地质灾害防治研究   总被引:2,自引:0,他引:2  
长江三峡水利工程是举世无双的宏伟工程,其水库的百万移民大都采取就地后靠安置,水库沿岸地质条件较复杂,滑坡、崩塌众多,地质灾害对移民的安全有重大影响,国家对三峡水库沿岸移民区的地质灾害防治给予高度重视,在几十年长期勘察研究的基础上,拨资进行现阶段的大规模地质灾害防治。防治工作有重大的社会、经济效益和较高的科学技术难度。  相似文献   

7.
Forest fires are almost always heterogeneous, leaving less-disturbed sites that are potentially suitable as habitats for soil-dwelling creatures. The recovery of large soil animal communities after fires is therefore dependent on the spatial structure of the burned habitats. The role of locally less disturbed sites in the survival of soil macrofauna communities along with traditionally considered immigration from the surrounding undisturbed habitats is shown by the example of burnt areas located in three geographically distant regions of European Russia. Such unburned soil cover sites (perfugia) occupy 5–10% of the total burned habitats. Initially, perfugia are characterized by much higher (200–300% of the average across a burned area) diversity and abundance of soil fauna. A geostatistical method made it possible to estimate the perfugia size for soil macrofauna at 3–8 m.  相似文献   

8.
李哲 《地质科学》1979,14(2):151-156
引言戈斯(Ghose,S.)在测定斜方辉石的结构时,首次发现Fe2+离子择优占据M2晶位,而Mg2+离子择优占据M1晶位。这一事实,引起了矿物学家的极大注意。  相似文献   

9.
The Wildlife and Countryside Act 1981 was passed to provide strengthened legal protection for threatened wildlife and environmental features in Britain. Limestone pavements were included specifically in section 34 of this act because their unique features were being damaged or destroyed through various causes. Limestone Pavement Orders (LPOs) are made under this act. This review considers why this protection became necessary, how the legislation is being implemented, what problems have arisen during implementation, and what progress has been made in making LPOs. Enforcement of the law, monitoring of sites after LPOs have been made, and management of pavement sites are discussed with reference to limestone pavements in NW England. Effectiveness of the legislation is difficult to assess because legal processes are incomplete, but there are indications that it is being effective in Britain. However, commercial threats to these landforms may simply have been shifted to Eire. The British experience with legal protection of these fragile karst features may aid conservationists in other nations.  相似文献   

10.
The protection for historical and cultural heritage and their surrounding environments is much more important than any other preventive efforts made by humans, so how to protect them and achieve sustainable utilization should be a priority. Regionalization is an efficient and a sustainable tool to manage the protected areas. In this study, based on regionalization of natural protected areas theory, we used ecological sensitivity analysis to regionalize the heritage sites in Turpan, China. Factors for the analysis are topography, ecological environments, human activity, and landscape resources. Based on the analysis of environmental status and spatial variation of ecological sensitivity in Turpan, this paper aims at developing a regionalization scheme and provides a scientific basis for protection and restoration of vulnerable historical and cultural sites. Our study results showed that 75% of the heritage sites in Turpan have sensitivity which is under dangerous condition and requires better planning and protection. This study provided a reliable and scientific way to regionalize heritage sites in the study area and which also can be transferred to other locations with similar situation.  相似文献   

11.
The widespread sheets of fine particulate sediment frequently deposited by tsunami constitute valuable evidence from which to reconstruct tsunami inundation. This is illustrated with evidence from three sites near Montrose, in eastern Scotland, U.K., where a horizon of mainly sand, laid down during the Holocene Storegga Slide palaeotsunami of circa 8000 BP is examined. The horizon is remarkably consistent in its distribution, morphology, stratigraphy, and particle size characteristics. These properties allow inferences to be made on the nature of tsunami flow onshore and run-up. It is suggested that estimates can be made of the possible depth of water involved from the characteristics of the sediment, and thus of the extent of inundation involved in the tsunami at these sites.  相似文献   

12.
Proper characterizations of background soil CO2 respiration rates are critical for interpreting CO2 leakage monitoring results at geologic sequestration sites. In this paper, a method is developed for determining temperature-dependent critical values of soil CO2 flux for preliminary leak detection inference. The method is illustrated using surface CO2 flux measurements obtained from the AmeriFlux network fit with alternative models for the soil CO2 flux versus soil temperature relationship. The models are fit first to determine pooled parameter estimates across the sites, then using a Bayesian hierarchical method to obtain both global and site-specific parameter estimates. Model comparisons are made using the deviance information criterion (DIC), which considers both goodness of fit and model complexity. The hierarchical models consistently outperform the corresponding pooled models, demonstrating the need for site-specific data and estimates when determining relationships for background soil respiration. A hierarchical model that relates the square root of the CO2 flux to a quadratic function of soil temperature is found to provide the best fit for the AmeriFlux sites among the models tested. This model also yields effective prediction intervals, consistent with the upper envelope of the flux data across the modeled sites and temperature ranges. Calculation of upper prediction intervals using the proposed method can provide a basis for setting critical values in CO2 leak detection monitoring at sequestration sites.  相似文献   

13.
广东雷州半岛玄武岩地下水水文地球化学特征及演化模拟   总被引:2,自引:0,他引:2  
应用水化学分析软件和水-岩作用模拟软件对雷州半岛的水文地球化学进行了分析和路径模拟。沿东、西2个地下水径流方向从一级台地补给区至二级台地、三级台地排泄区的模拟计算结果表明,地下水可能经历了一系列复杂的水-岩作用,包括石膏、高岭石、钙蒙脱石、伊利石、绿泥石、斜辉石(或透辉石)、针铁矿、赤铁矿的溶解或沉淀及CO2气体的溶解或逸出等地球化学反应。针铁矿、赤铁矿和透辉石的溶解或沉淀量在沿东面地下水径流方向上远小于沿西面方向;针铁矿和赤铁矿只在少量水点发生溶解进入地下水,在大多数水点处于饱和状态而从地下水中析出;CO2气体在大多数取样点发生溶解进入地下水中,其溶解量较大,且随着CO2在水中浓度的变大,其饱和指数也增大,达到饱和后从水中逸出。可见水-岩作用模拟结果有助于揭示研究区地下水化学环境的演化机制。  相似文献   

14.
This study focuses on the compound pahoehoe lava flow fields of the 2000 eruption on Mount Cameroon volcano, West Africa and it comprehensively documents their morphology. The 2000 eruption of Mount Cameroon took place at three different sites (sites 1, 2 and 3), on the southwest flank and near the summit that built three different lava flow fields. These lava flow fields were formed during a long‐duration (28th May–mid September) summit and flank eruption involving predominantly pahoehoe flows (sites 2 and 3) and aa flows (site 1). Field observations of flows from a total of four cross‐sections made at the proximal end, midway and at the flow front, have been supplemented with data from satellite imagery (SRTM DEM, Landsat TM and ETM+) and are used to offer some clues into their emplacement. Detailed mapping of these lava flows revealed that site 1 flows were typically channel‐fed simple aa flows that evolved as a single flow unit, while sites 2 and 3 lava flow fields were fed by master tubes within fissures producing principally tube‐fed compound pahoehoe flows. Sites 2 and 3 flows issued from ∼ 33 ephemeral vents along four NE–SW‐trending faults/fissures. Pahoehoe morphologies at sites 2 and 3 include smooth, folded and channelled lobes emplaced via a continuum of different mechanisms with the principal mechanism being inflation. The dominant structural features observed on these flow fields included: fissures/faults, vents, levees, channels, tubes and pressure ridges. Other structural features present were pahoehoe toes/lobes, breakouts and squeeze‐ups. Slabby pahoehoe resulting from slab‐crusted lava was the transitionary lava type from pahoehoe to aa observed at all the sites. Transition zones correspond to slopes of > 10°. Variations in flow morphology and textures across profiles and downstream were repetitive, suggesting a cyclical nature for the responsible processes. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

15.
During 1987, in situ stress measurements using two overcoring techniques (doorstopper and triaxial strain cell) were made in England and Scotland as part of the former SFB 108 Project ‘Stress and Stress Release in the Lithosphere’ at Karlsruhe University. The results for three of the test sites—Spittal in Caithness, Gartur in the Midland Valley of Scotland and at Burton in Cumbria—are reported. Complementary studies on cores from Gartur using portable ASR equipment are included. The maximum horizontal stress orientations agree closely with those seen in the general contemporary stress field in NW Europe. These results confirm that, in favourable circumstances, these shallow methods offer effective approaches to the acquisition of reliable contemporary stress information, whether derived from boreholes or rock cores.  相似文献   

16.
GPS-derived deformation rates in northwestern Himalaya and Ladakh   总被引:1,自引:0,他引:1  
Deformation rates derived from GPS measurements made at two continuously operating stations at Leh (34.1°N, 77.6°E) and Hanle (32.7°N, 78.9°E), and eight campaign sites in the trans-Himalayan Ladakh spanning 11 years (1997–2008), provide a clear picture of the kinematics of this region as well as the convergence rate across northwestern Himalaya. All the Ladakh sites move 32–34 mm/year NE in the ITRF2005 reference frame, and their relative velocities are 13–16 mm/year SW in the Indian reference frame and ~19 mm/year W with reference to the Lhasa IGS station in southeastern Tibet. The results indicate that there is no statistically significant deformation in the 200-km stretch between the continuous sites Leh and Hanle as well as between Leh and Nubra valley sites along the Karakoram fault, whereas the sites in and around the splayed Karakoram fault region indicate surface deformation of 2.5 mm/year. Campaign sites along the Karakoram fault zone indicate a fault parallel surface motion of 1.4–2.5 mm/year in the Tangste and western Panamik segment of the Karakoram fault, which quantifies the best possible GPS-derived dextral slip rate of 3 mm/year along this fault during this 11-year period. Baselines of Ladakh sites show convergence rates of 15–18 mm/year with respect to south India and 12–15 mm/year with respect to Delhi in north India and Almora in the Himalaya ~400 km north-northeast of Delhi. These constitute an arc normal convergence of 12–15 mm/year across the western Himalaya, which is consistent with arc normal convergence all along the Himalayan arc from west to east. Baseline extension rates of 14–16 mm/year between Lhasa and Ladakh sites are consistent with the east–west extension rate of Tibetan Plateau.  相似文献   

17.
彭阳草庙地区是宁夏南部山区深部煤炭资源勘查的重要地区之一。在钻探过程中,多数钻孔都遇到不同程度的漏失问题,部分钻孔由于漏失诱发了孔内事故或机械事故,最终导致报废。在现场调研的基础上,针对不同漏失地层的防漏堵漏对策进行了分析;通过室内试验评价得到对应的防漏堵漏配方与实施细则;在以ZK7-1孔为代表的多个钻孔展开现场试验,效果良好,可在该地区或国内类似地区进行推广。  相似文献   

18.
The distribution of 75 lake and bog sites, from which pollen stratigraphical evidence relevant to the late Quaternary of Newfoundland has been obtained, is presented. The detailed records of lithology, pollen and diatoms, supplemented by geochemical data, are discussed for three of the sites — Southwest Brook Lake, Woody Hill Brook Pond and Leading Tickles — and interpretations made are based on vegetational history, relative climatic changes and extent of ice cover. Radiocarbon data from 14 sites are summarised. A summary chart of Late-glacial environmental changes, including a qualitative palaeotemperature curve, is provided.  相似文献   

19.
This article demonstrates the application of multiple reconnaissance methods as an efficient means of localizing desired data sets (e.g., artifact concentrations and architectural features) in stratigraphically complex sites. Excavations at Blagotin, Serbia, are presented as an example. Blagotin is a multioccupation site with vertically superimposed and laterally displaced cultural deposits. The application of a battery of survey techniques and the integration of the results enabled the author to define periods of occupation (Early Neolithic, Eneolithic, Early Iron Age), distinguish temporal variations, and predict the nature and distribution of subsurface archaeological remains. Ultimately, the Early Neolithic occupation is shown to consist of a small settlement with a large central pit‐house surrounded by a ring of smaller pit houses. This interpretation of the intra‐settlement spatial organization, made possible through the application of a multiple survey technique, differs from those previously offered for these types of sites. © 2000 John Wiley & Sons, Inc.  相似文献   

20.
The till-covered organic sediments at Leveäiemi, Swedish Lapland have been reinvestigated by pollen analysis in order to gather more detailed information on vegetation history and climatic conditions during the interglacial period represented at this site. A partly different picture of the vegetation succession has arisen compared to earlier studies and results. The organic sequence is still correlated with the Eemian, but the forests were probably more open during the initial and later parts of the interglaciation than suggested earlier. This is based on the higher values of Juniperus pollen noted, and a continuous curve for Populous pollen during the PAZ representing the later part of the interglaciation. Comparisons are made with other sites in northern Sweden, Finland and northern Norway, and the possibilities of separating Eeinian deposits from those formed during the Holsteinian interglaciation are discussed.  相似文献   

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