Investigation on strength and stability of jointed rock mass using three‐dimensional numerical manifold method

This paper proposes a numerical model for jointed rock masses within the 3‐D numerical manifold method (NMM) framework equipped with a customized contact algorithm. The strength of rock sample containing a few sets of discontinuities is first investigated. The results of models with simple geometries are compared with the available analytical solutions to verify the developed computer code, whereas models with complex geometries are simulated to better understand the fundamental behavior and failure mechanism of jointed rock mass. Furthermore, the stability of jointed rock mass in an underground excavation is studied, where rock failure process is determined by the 3‐D NMM simulation. The simulation results provide valuable guidance on excavation process design and stabilization design in rock engineering practice. Copyright © 2012 John Wiley & Sons, Ltd.     

Random wave-current interactions in water of varying depth

Refraction of incoherent random gravity waves with currents and bottom topography results in spatial variations in the spectral characteristics of the free surface. Prediction of such variations based on the radiation transfer equation is in a simple analytic form for the case of one dimensional inhomogeneities in currents and topography. This analytic form is examined in terms of two-dimensional wave number- and polar frequency-direction spectra along the associated dynamic and kinematic constraints relevant to wave breaking and reflection. Results are specialized to the simplest case of horizontal shear currents in deep and shallow water with explicit examples to illustrate the relative and combined effects of currents and topography on free surface spectra.     

Evolution of sedimentary basins from the standpoint of petroleum origin and accumulation—an approach for a quantitative basin study

Generation, migration and accumulation of petroleum in a sedimentary basin is a function of geologic, hydrodynamic and thermodynamic development of the basin and the type and amount of organic matter. Temperature history not only determines rate of hydrocarbon generation, but also affects paleohydrodynamics and physical and thermal properties vs depth relationships. Therefore, paleotemperature is the most important parameter. Paleohydrodynamics together with geologic history of the basin is important in shaping secondary migration patterns and accumulation of hydrocarbons.Quantification of all the above processes is complicated. Steps in constructing a deterministic dynamic model for calculation of petroleum potential during a sedimentary basin development are stated and analyzed in this paper. The effect of paleotemperature variations on petroleum generation and on physical properties of sedimentary sequences are illustrated by numerical examples. Computer models will enable exploration geologists to make quantitative exploration predictions in sedimentary basins.     

THINNED POLISHED SECTION OF COAL,A NEW TECHNIQUE IN COAL PETROGRAPHY

Opinions often differ among coal petrographers as to the relative ad-vantages of the thin sections and the polished sections.In reality both of themare useful and they should be used simultaneously in order to get a clear and     

WORLD ATLAS OF THEMATIC MAPS OF DESERTIFICATION

The author describes the contents and participation of former Soviet republics in the compilation of a global atlas of desertification, published under the auspices of the United Nations. Translated by H. L. Haslett, Leamington Spa, UK, from: Izvestiya Akademii Nauk SSSR, seriya geograficheskaya, 1991, No. 6, p. 130.     

Prediction of surface horizontal displacements, and gravity and tilt changes caused by filling the Three Gorges Reservoir

 Horizontal displacements, and gravity and tilt changes induced by filling the Three Gorges Reservoir are modeled using elastic loading Green functions. When the water surface reaches its highest level, the effects become maximum on the reservoir banks. The longitudinal and latitudinal components of the horizontal displacements reach −8.2 and 7.7 mm respectively, gravity is increased by up to 3.4 mGal, and the prime vertical and meridian components of the tilt changes are −7.8 and −17.5 arcseconds respectively. Accordingly, the filling of the reservoir will influence values observed from global positioning system (GPS), gravimetry and tilt measurements in the area. The results given can be used to provide important corrections for extracting earthquake-related signals from observed data. Received: 19 January 2001 / Accepted: 3 September 2001     

Alteration in CM carbonaceous chondrites inferred from modal and chemical variations in matrix

The modal abundance of matrix in CM chondrites appears to vary from 57–85 vol%. The concentrations of volatile elements that should occur in matrix remain approximately constant despite differences in the proportions of matrix, suggesting that the differing matrix contents may not be real primary variations but are optical effects due to aqueous alteration processes that make other petrologic components unrecognizable. Apparent matrix content can be used as a qualitative measure of the degree of alteration experienced by each CM chondrite. Fe/Si ratios in matrices decrease progressively with increasing alteration due to the formation of new phyllosilicate phases with higher Mg/Fe ratios and optically recognizable opaque minerals that are not counted as matrix. The aqueous alteration process in CM chondrites appears to have been largely isochemical if the bulk meteorites are considered as the reacting systems, although depletion patterns and isotopic anomalies indicate open-system behavior for a few highly mobile components.     

哈萨克斯坦共和国地震学数据库简介

建立哈萨克斯坦共和国地震学数据库是CASIN国际项目的一部分,应由中亚各国来共同完成。项目主要目的旨在建立地震学数据库,以作为今后减小哈萨克斯坦共和国地震危险性的工作基础。哈萨克斯坦共和国地震学数据库由下列子系统构成:1)文件输入子系统;2)信息检索和提交子系统;3)信息元数据存储子系统;4)档案库运行控制子系统;5)信息安全子系统。哈萨克斯坦共和国地震学数据库有以下功能:1)永久存储综合信息并上报和收集(记录)其他资料;2)存储数据和资料计算;3)电子文档的长期存储和管理;4)规定序号进行信息查询和文件的联机保证;5)信息统计和…     

Intersexes in Mississippi River shovelnose sturgeon sampled below Saint Louis, Missouri, USA.

The Missouri Department of Conservation detected high organochlorine levels in tissues of fish from the Mississippi River south of Saint Louis. Chlordane, which is both a carcinogen and an endocrine disrupter, reached 2960 micrograms/kg in fillets of shovelnose sturgeon, Scaphirhynchus platyorynchus, and 1926 micrograms/kg in their roe, wet weight basis. Polychlorinated biphenyls (PCBs) and p,p'-dichlorodiphenyldichloroethylene (DDE) in roe have reached 5810 and 780 micrograms/kg, respectively. The purpose of this study was to determine if endocrine disrupters and carcinogens are a potential cause of the significantly diminished reproduction capacity and population declines in the endangered pallid sturgeon, Scaphirhynchus albus. Twenty-four surrogate shovelnose sturgeons were sampled north of Saint Louis where contaminant levels were lower compared with 17 sampled south of Saint Louis where contaminant levels were high. Liver and gonad tissues were formalin-fixed, histologically processed and examined. Neoplasms were not found. The principal finding was that the testes of two of the seven downstream male fish contained ovigerous lamellae, in addition to mature sperm. Since sturgeons are gonochoristic and intersexes are rare and unusual, the occurrence of intersex in 29% of the male Mississippi River shovelnose sturgeon examined from a population contaminated with chlordane and other chemicals raise concern for human health, species biodiversity and preservation of waterway quality. These findings, however, need to be corroborated by expanded studies with a higher sample size.