共查询到20条相似文献，搜索用时 31 毫秒
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Mathematical Geosciences - 相似文献
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Methodology for geohazard assessment for hydropower projects 总被引：1，自引：0，他引：1
Fjóla G. Sigtryggsdóttir Jónas Th. Snæbjörnsson Lars Grande Ragnar Sigbjörnsson 《Natural Hazards》2015,79(2):1299-1331
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《Russian Geology and Geophysics》2015,56(7):1074-1082
We consider possible approaches to the long-term prediction for seismic hazard in relation to the practical need for the safety of geological disposal of long-lived radioactive waste. The required period of prediction significantly exceeds the one reflected in the set of maps of General Seismic Zoning of the territory of the Russian Federation (GSZ-97). The first geological repository in Russia is planned to be set up in the Nizhnii Kan granite massif in the Krasnoyarsk Krai. This region is an intraplate territory with a relatively high seismic activity. We summarize the analysis of the known empirical generalizations and theoretical principles underlying the seismic hazard prediction. Real seismic events constantly violate forward-looking statements even for relatively short periods of time. These and other arguments suggest that the hypothesis of stationarity of the seismic regime, which is the basis of long-term prediction today, has limited and uncertain applicability in time. Intraplate earthquake prediction is especially uncertain because of the uncertainty in the factor responsible for generating tectonic stresses in these regions. The short horizon of the prediction, based on statistical methods, can be attributed to the nonlinearity of seismic geodynamic processes. Fundamental laws of tectonic processes should be used as the scientific basis for long-term predictions for seismic hazard at the sites chosen for geological disposal of long-lived radioactive waste. These processes can be reflected in models for the migration of the seismically active boundaries of lithospheric plates and the occurrence of seismic activity in intraplate regions. 相似文献
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A new approach for calculating strain for particulate media 总被引：1，自引：0，他引：1
Discrete element modelling is a viable alternative to conventional continuum‐based analysis for analysing problems involving localized deformations of particulate media. However, to aid in the interpretation of the results, it is useful to express the results of discrete element analyses in terms of the continuum parameters of stress and strain. A number of homogenization methods have been proposed to calculate strain in discrete systems; however, two significant limitations of these methods remain. First, none of these methods incorporate particle rotation effects satisfactorily, although significant particle rotation occurs in shear bands in both physical tests and numerical simulations of granular materials. Additionally, observations of the particle displacement fields in shear bands in granular materials indicate that the displacements within the localizations are erratic. Consequently, existing linear, local interpolation approaches produce substantial variations in the strain values calculated in adjacent elements in the region of localization, hindering clear visualization of the strain localization as it evolves. A new method of domain discretization for calculating strain is proposed. This method is capable of capturing particle rotation and employs a non‐local meshfree interpolation procedure capable of smoothing the erratic displacements in strain localizations, which better defines their evolution. The proposed method is validated for problems involving both two and three dimensions. A number of methods are compared with the proposed method and pertinent insights are made. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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Current methods of establishing suitable locations for onsite wastewater treatment systems (OWTS) are inadequate, particularly in light of the numerous cases of onsite system failure and the resulting adverse consequences. The development of a soil suitability framework for assessing soil suitability for OWTS allows a more practical means of assessment. The use of multivariate statistical analysis techniques, including Principal Component Analysis (PCA) and multi-criteria decision aids of PROMETHEE and GAIA, enabled the identification of suitable soils for effluent renovation. The outcome of the multivariate analysis, together with soil permeability and drainage characteristics permitted the establishment of a framework for assessing soil suitability based on three main soil functions: (1) the ability of the soil to provide suitable effluent renovation, (2) the permeability of the soil, and (3) the soils drainage characteristics. The developed framework was subsequently applied to the research area, Gold Coast, Queensland, Australia, and the use of standard scoring functions were utilised to provide a scoring system to signify which soils were more suitable for effluent renovation processes. From the assessment, it was found that Chromosol and Kurosol soils provided the highest level of effluent renovation, closely followed by Ferrosol and Dermosol, Kandosol and Rudosol soil types. Tennosol and Podosol soil types were found to have a significantly lower suitability, with Hydrosol soils proving the least suitable for renovating effluent from OWTS. 相似文献
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我国海洋生态调查指南编制说明 总被引：1，自引：0，他引：1
海洋生态调查的主要目的是了解海洋生态系统基本的群落结构和生态功能及其重要影响因素,掌握生态系统健康状况，把握其变化趋势。基于生态系统健康理论建立我国海洋生态调查的基本框架体系，编制了我国海洋生态调查指南。根据目前的技术设备、实用方法和经费限制，确定最能反映我国海洋生态系统特征的生态要素和评价内容，并规定了相应的调查和评价方法。与《海洋调查规范海洋生物调查》和《海洋监测规范》比较，该指南具有3个显著特点：①调查要素不仅包括海洋生物和海洋环境等自然要素，还包括人为活动要素，充分考虑我国近海生态系统的高强度开发利用的特点；②从生态系统的结构、功能和压力3个方面建立起海洋生态系统健康评价的核心框架体系；③提出生态压力的量化指标，定量评估人类活动对生态系统的压力。 相似文献
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湘南地区蕴藏着丰富的锡矿资源,锡及锡多金属矿矿床(点)分布广泛,类型复杂,它们的形成除与花岗质侵入岩体直接相关外,同时还受到区域地层和地质构造等因素的共同制约。通过对锡矿的地质背景、分布特征、矿床特征与矿化规律、矿床成因及找矿信息和标志的研究,把湘南地区锡矿的找矿归纳为:"划带、圈区、寻体、定位"的找矿模式,不仅从宏观上提出了或解决了锡矿找矿方向的问题,而且近几年来的地质找矿工作得到了实践应用,并取得了丰硕的找矿成果。 相似文献
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Recent emergency flood situations at European rivers have revealed the demand for better and in-time information for citizens
in flood prone areas about flood development, as well as better coordination of resources and actions during pre-flood phases
and its critical stage. Information and Communication Technology (ICT) has a large potential to improve the situation. Decisions
may be supported by information about resources available at the region and national level, by information about means and
access to critical locations at the prevention as well as the evacuation phases, and by including citizens as well as managers
into one common information and communication process. The paper outlines the potential of ICT for these aspects. 相似文献
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An empirical model for investigating the behaviour of CaCO3 polymorphs incorporating a shell model for oxygen has been created. The model was constructed by fitting to: the structure of aragonite and calcite; their elastic, static and high-frequency dielectric constants; phonon frequencies at the wave vectors [&frac; 0 2] and [0 0 0] of calcite; and vibrational frequencies of the carbonate deformation modes of calcite. The high-pressure phase transition between calcite I and II is observed. The potentials for the CO3 group were transferred to other carbonates, by refitting the interaction between CO3 and the cation to both the experimental structures and their bulk modulus, creating a set of potentials for calculating the properties of a wide range of carbonate materials. Defect energies of substitutional cation defects were analyzed for calcite and aragonite phases. The results were rationalized by studying the structure of calcite and aragonite in greater detail. 相似文献
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建设用地定额标准是控制土地利用的有效工具。近年来各地高等院校建设快速发展,而相关的用地标准涵盖内容不全,致使新建校区用地规模过大、容积率偏低等问题较为普遍。通过对教育部及北京、江苏、上海等省市相关的高校用地定额标准的对比分析,并结合上海部分高校的调查,提出合理确定规划指标、优化土地利用结构布局与比例等完善高校用地定额标准的建议。 相似文献
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Despite being a simple and inexpensive pretreatment technology, the cost-effectiveness of riverbank filtration (RBF) depends on complex hydrogeological and hydrogeochemical variables. One of the most important issues for decision makers regarding RBF is optimal site selection. Therefore, a methodology for multicriteria site evaluation for large-scale RBF schemes is offered. The methodology is primarily designed as a prescreening method, applied over a wide area, but can also serve as a guide for evaluating individual RBF sites. To facilitate further discussion about improvements on the methodology, the reasoning behind each relevant factor and its weight in the evaluation is presented. The methodology is divided into three sequential steps through which a site can be assessed. The first step is to establish the existence of connectivity between the river and aquifer. This is termed the essential criterion, and is a binary determination of site suitability. If the site is determined to be suitable, it is then assessed via a set of quantity criteria, which measure the aquifer capacity and amount of bank filtrate that can be effectively abstracted. Lastly, water quality criteria are assessed by means of surface-water and groundwater quality. The quantity and quality criteria form a result expressed as the site suitability index (SSI), which ranges from 0 to 1, where higher scores represent increased suitability. Finally, the methodology is applied to evaluate existing sites of large-scale RBF application as a demonstration of its applicability. The success of these existing sites is compared to the calculated SSI value and discussed.
相似文献12.
Qualitative geological acceptance criteria and quantitative seismological acceptance criteria for radioactive waste disposals are developed. The background material for the initiation of site selection and for its earthquake hazard assessment is discussed. The recent movements of the Earth's surface as well as the other mechanical properties of geological media, hydrological conditions of geological blocks, their groundwater chemistry, geochemical rheology, petrological analyses of rocks, etc., have to be taken into account. A new comprehensive integrated safety analysis of the final underground disposal of spent nuclear fuel has been underway in the Czech Republic since 1991. In accordance with these seismogeological acceptance criteria regions for building underground final radioactive waste disposals are singled out in the Czech Republic. 相似文献
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A novel application of multi-criteria decision making (MCDM) technique to seismic soil liquefaction, a complex problem in earthquake geotechnical engineering, is presented. Seismic soil liquefaction depends on a diversified set of physical parameters with highly non-linear interconnections. Factors governing liquefaction may broadly be grouped as seismic parameters, site conditions and primarily dynamic soil properties, as the stimulus itself is manifestly dynamic. Each of these factors incorporates a wide range of variety of parameters that characterize liquefaction, to a varying degree of significance, such as: the magnitude, effective overburden pressure, shear modulus, normalized standard penetration blow count [N1]60, etc. Estimating rapid, yet accurate and reliable liquefaction susceptibility requires identification of the most significant factors controlling liquefaction. Thus a new concept of extracting significant parameters and gauging their importance is carried out by assigning them weights by applying MCDM introduced herein, whose evaluation is accomplished by means of an ‘entropy method’. In line with this, a relative reliability risk index (R3I) is computed indicating the ranking that directly reflects the severity of risk for liquefaction. Although the entropy analysis is carried out separately for the three multivariate criteria, it is remarkable that the R3I evaluated for each of these gives consistent ranking. 相似文献
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A. E. Lucas 《GeoJournal》1996,39(2):133-142
Geographic information systems can provide easy access to large quantities of geographically-referenced data for monitoring, planning and environmental decision support for coastal applications. The dynamic and variable nature of the coastal ocean environment gives rise to data issues different than those associated with land-based GIS. This paper investigates, in particular, the use of different data, including those produced by numerical simulations or ocean models, for coastal management and is illustrated with examples from a Baltic Sea GIS implementation. Implications for the use of these data in environmental management are discussed. 相似文献
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Length distributions from sedimentary bodies can be measured in outcrop. A common feature in many outcrops is the occurrence of partially exposed bodies, i.e., sedimentary bodies that are cut by either one or both edges of the outcrop. Ignoring these partials while establishing a length distribution leads to a bias toward the smaller length classes. This is because larger bodies have a larger probability to occur as partials than smaller bodies. We present a new method for estimating the expected complete length for a partially exposed feature, based on the theory of conditional probability. The method is demonstrated and tested on a sandstone outcrop exhibiting over 200 interbedded thin silt/shale streaks. It is shown that the method can significantly enlarge both the size and the representativeness of length distributions. 相似文献
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Acta Geotechnica - The hypoplastic model for sands proposed by Wolffersdorff (Mech Cohes Frict Mater 1: 251–271, 1996) combined with the intergranular strain anisotropy by Fuentes and... 相似文献
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V. Nath 《GeoJournal》1993,29(2):171-180
This paper reviews the planning and city building processes in Delhi in three periods — the imperial Mughal, the imperial British and the post-Independence. In the two earlier periods, the plans followed the ideals and tastes of the ruling elites and the cities were built to meet their needs. But the cities were well adapted to the technologies of the times and patterns of social interactions among the residents. Consequently, they provided to most of their residents a living environment which was efficient, healthy and satisfying. One reason for this was that Delhi was a relatively small city and increase in population was slow.The half century since 1941 has witnessed an unprecedented increase in population which has gone up from less than 700,000 in 1941 to 8.4 million in 1991. The increase has been due partly in response to expansion of employment in public administration, trade, finance and manufacturing industries, and partly to large in-migration of displaced persons from Pakistan during 1947–48, and from other states of India throughout the period.The efforts of the public agencies — the Central Government and the Delhi Development Authority — to expand housing have been matched by those of individuals and cooperative societies. But the efforts have been focussed on providing housing to people of medium and high income groups; the housing needs of the poor have been met by rapid growth of slums and unauthorised colonies. Expansion of physical and social infrastructure has also proved inadequate to meet the demands on it. The reliance in the absence of a mass transit facility, on a miscellany of motor vehicles for movement within the city, has resulted in very high levels of air and noise pollution.The hopeful beginning with long-term planning, made with successful implementation of the first master plan 1961–81, has suffered a set back as a result of the failure of the Central Government to approve the second master plan 1981–2001. The Regional Plan 2001 for the National Capital Region, approved in 1988 by all the governments concerned, is also not being implemented. In the resulting, impasse there is unplanned growth of a giant conurbation adding to its various problems. The paper recommends revival of metropolitan and regional planning for direction of growth of the conurbation to 2010. 相似文献
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准确地确定岩土设计参数统计特征值诸如均值、标准差是岩土工程可靠度分析与设计的重要前提。在满足岩土设计参数统计特征值计算精度条件下,文中提出了岩土工程最小勘探数据量的确定方法,定义了相对误差和相对变异性指标衡量岩土设计参数统计特征值计算准确性。系统地分析了静力触探试验数据量对砂土有效内摩擦角统计特征值计算精度的影响,并且根据相对误差和相对变异性指标确定了静力触探最小勘探数据量。研究结果表明,由静力触探试验间接估计砂土有效内摩擦角时均值相对误差较低,砂土有效内摩擦角相对变异性指标随静力触探试验数据量的增加而降低,即由认知不足引起的不确定性占总变异性的比值随静力触探试验数据量的增加而减小;当砂土有效内摩擦角容许相对变异性指标小于0.2时砂土有效内摩擦角在最大变异（COV=20%）与最小变异性（COV=5%）范围内,满足预定要求所需的最小静力触探试验数据量为10～100;若容许相对变异性指标小于0.3,所需的最小静力触探试验数据量为5～43。此外,间接估计岩土设计参数时经验回归模型不确定性对最小勘探数据量有显著影响。静力触探试验最小勘探数据量随经验回归模型不确定性的增大而增加,在确定岩土设计参数统计特征值时应尽量广泛收集勘探数据并选择精度较高的计算模型。 相似文献