Large strain similarity solution for a spherical or circular opening excavated in elastic‐perfectly plastic media

This paper deals with the unloading problem of a spherical or circular opening excavated in elastic‐perfectly plastic media with a nonassociated Mohr–Coulomb yield criterion. A large strain similarity solution, using incremental velocity approach, is presented by replacing partial differential equations from stress equilibrium, constitutive law, consistency condition, and displacement equation with first‐order ordinary differential equations. The classical Runge–Kutta method is used to solve the first‐order ordinary differential equations. Comparisons among small and large strain solutions are made using some data sets of soil and rock. The results show that the displacements by large strain similarity solution are smaller than those by exact small strain solution and somewhat larger than those by large strain solution using total strain approach. Copyright © 2014 John Wiley & Sons, Ltd.     

寒区公路风吹雪害的融雪侵蚀破坏机理研究

以寒区公路路基作为研究对象,采用与天然老的细粒雪密度相似的麸皮作为模型雪,通过室内风洞试验研究雪粒子的起动以及沿路基不同部位堆积和积蚀的过程,确定雪粒子沿路基坡面堆积区域与路基断面之间的关系．通过FLAC数值模拟,考察融雪径流对路基的侵蚀作用;引入融雪侵蚀面积率,研究了融雪侵蚀面积率随融雪量、土体饱和度、路基边坡坡率以...     

Observed and simulated Lagrangian and eddy characteristics of the East Australian Current and the Tasman Sea

New insights into the Lagrangian and eddy dynamical processes within the East Australian Current (EAC) and the Tasman Sea are presented. We briefly discuss the past campaigns undertaken to observe the EAC and the Tasman Sea eddies as well as the motivation to renew the deployment of drifting buoys into the EAC and the Tasman Sea. The specific features discussed are motivated by the recent observing campaigns using drifting buoys and the availability of high spatial- and temporal-resolution estimates of the ocean state and circulation from eddy resolving models. The interpretation of these features is also aided by other components of the ocean observing system. The dynamics presented includes: (a) transient EAC separation through a vortex dipole, (b) stratified vortex mergers and secondary circulation of EAC eddies, (c) eddy networks in the Tasman Sea and (d) formation and propagation of the EAC separation point. The importance of these dynamical features to the EAC and the Tasman Sea and their implications for the observing system and modelling are discussed.     

我国开放型经济研究进展及展望

在经济全球化与区域一体化的时代背景下,开放型经济成为各国或地区发展经济所追逐的焦点。改革开放以来我国的开放型经济取得了长足的发展,对开放型经济的研究也十分丰富。我国开放型经济的研究内容主要包括:开放型经济的内涵、影响因素、发展阶段、发展特征、发展战略、发展模式以及研究方法等等。这些研究多以现状的描述为主,并没有形成完整的理论体系。在我国继续扩大开放的大背景下,开放型经济发展必将成为我国经济发展的重点。今后的研究中在继续关注东部沿海地区和沿边地区的同时要加大对中西部地区的研究力度,要加强区域间的联动,在全球化的新背景下研究新的开放型经济发展模式和研究方法。     

Cenozoic wrench tectonics and oroclinal bending in SE Korea

Based on fault geometry, petrography, and geochronology of granitic rocks as well as palaeomagnetic data from the Gyeongsang Basin, two conjugate fault sets are explained as a reflection of NNE-trending right-lateral wrench tectonics. According to this interpretation, the Gaum and Yangsan fault sets correspond to antithetic faulting by R′-shear and synthetic faulting by R-shear, respectively; they have rotated clockwise and counterclockwise, respectively, due to NE–SW compression (shortening), as a result of a NNE-trending wrenching force (simple shear). During progressive deformation, NS- or NNW-trending strike–slip faulting by P-shear occurred in the Yeongyang sub-basin, and finally the Yangsan fault formed as a wrench fault bisecting the P-shear and R-shear directions. Extension of the faults (R-shear, striking ～N22°E) generated by block rotation on the east side of the Yangsan fault (wrench fault, striking ～N13°E) resulted in convex eastward deflections. We suggest that this was caused by oroclinal bending of the existing faults generated by block rotations in opposite directions and is inferred to have been closely related to the East Sea (i.e. Sea of Japan) opening.     

过筛孔径对土壤可溶盐分析结果的影响

取11个土壤样品分别过0．5、1．0、2．0mm孔径筛,按规范要求在相同条件下分别测定可溶盐含量,根据可溶盐含量的变化规律,分析其对结果的影响,以寻找对可溶盐分析准确度和精密度都比较理想的过筛孔径。     

Studies of household activity patterns and urban structure

Simonsen, Kirsten, 1973: Studies of household activity patterns and urban structure. Geografisk Tidsskrift 73: 26–35. København, juni 1, 1974.

This Paper focuses upon the daily activity patterns of individuals and households. It gives a survey of the relevant literature and discusses the possible use of activity studies. Furthermore, it treats the interrelationship between activity patterns and environment and illustrates this by a case study from a Danish provincial town.     

Break Up of Australia-India-Madagascar Block, Opening of the Indian Ocean and Continental Accretion in Southeast Asia With Special Reference to the Characteristics of the Peri-Indian Collision Zones

Linear belts of Gondwana basins developed in the Indian continent since Late Palaeozoic along favoured sites of Precambrian weak zones like cratonic sutures and reactivated mobile belts. The Tibetan and Sibumasu - West Yunnan continental blocks, that were located adjacent to proto-Himalayan part of the Indian continent, rifted and drifted from the northern margin of the East Gondwanic Indo-Australian continent, during Late Palaeozoic, when the said northern margin was under glacial or cool climatic condition and rift-drift tectonic setting. The Indo-Burma-Andaman (IBA), Sikule, Lolotoi blocks were also rifted and drifted from the same northern margin during Late Jurassic. This was followed by the break-up of the Australia-India-Madagascar continental block during the Cretaceous. The activity was associated with hot spot related volcanism and opening up of the Indian Ocean. The Late Cretaceous and Tertiary phases of opening of the Arabian Sea succeeded the Early Cretaceous phase of opening of the Bay of Bengal, part of the Indian Ocean. The Palaeo- and Neo-Tethyan sutures in Tibet, Yunnan, Laos, Thailand and Vietnam reveal the complex opening and closing history of the Tethys. The IBA block rotated clockwise from its initial E-W orientation because of 90°E and adjacent dextral transcurrent fault movements caused due to faster northward movement of the Indian plate relative to that of Australia. The India-Tibet terminal collision during Early-Middle Eocene initiated Himalayan orogenesis and contemporaneously there was foreland basin development that was accompanied with sporadic but laterally extensive continental-flood-basalt (CFB) type and related volcanism. The Paleogene rocks of the Himalayan foreland basin are involved in tectonism and are mostly concealed under older rocks.

The Mesozoic-Early Eocene ophiolite terrane on IBA does not represent the eastern suture of the Indian plate but occurs as klippe on IBA, caused due to oblique collision between Sibumasu and IBA during Late Oligocene. Post-collisional indentation of Y-shaped Indian continent into the Asian collage produced Himalayan syntaxes, clockwise rotation of the Sibumasu block which was then sutured to the Tibetan and SE Asian blocks, and tectonic extrusion of the Indochina block along the Ailao Shan Red River (ASRR) shear zone. Highly potassic magmatic rocks were emplaced during Late Palaeogene at the oroclinally flexed marginal parts of the South China continental lithosphere. These magmatic bodies were dislocated by the ASRR left lateral shear zone soon afterwards. Petrogenetic and tectonic processes that generated the Eocene CFB volcanics at the Himalayan foreland basin may have also produced Late Palaeogene magmatism from outer parts of the Namche-Barwa Syntaxis. Their site-specific location and time sequence suggest them to be genetically related to the India-Asia collision process and Indian continent's indentation-induced syntaxial buckling. Deep mantle-reaching fractures were apparently produced during India-Asia terminal collision at the strongly flexed leading brittle edge of the Indian continental lithosphere, and possibly later in time at the outer oroclinally bent marginal parts of the rigid South China continental lithosphere, generating typical magma.

The subduction zone that developed along the western margin of IBA due to oblique convergence between the IBA and the Indian plate is still active. The northern end of IBA ultimately collided with the NE prolongation of the Indian continent and was accreted to it during Mio-Pliocene. The Shillong massif was uplifted and overthrust over the Bengal Basin located over its passive margin to the south, whereas, the Eocene distal shelf sediments of IBA were overthrust over the Tertiary shelf of the Indian continent.     

Assessing the implications of the recent community opening policy on the street centrality in China: A GIS-based method and case study

Recently, the Chinese government raised an urban planning policy which suggests communities open their private roads for public transport and establish street networks with high spatial density in cities. In this context, the purpose of this study is to analyze the potential changes to street network accessibility using GIS techniques and to provide spatial information that may influence the decision making of urban managers. In addition to the existing street network data in the case study city, Shenzhen, intra-community roads are extracted from building footprints in GIS topographic database and used to construct a potential street network with respect to the community opening policy. An automatic GIS-based method is proposed here to analyze the location advantage information in the simulated urban environment, by combining Delaunay triangulation model and graph theory concepts. Specifically, we establish a two-step framework based on the spatial relationships between roads and buildings. Firstly, intra-community roads between neighboring building footprints are generated using a Delaunay triangulation skeleton model, and with the existing inter-community roads they form the simulated network. Secondly, street centrality indices of the current and simulated networks are compared in terms of closeness, betweenness and straightness. Results indicate that after applying the policy the global accessibility in the city would be increased at some places and decreased at others, and places' directness among others would be generally improved. In addition, the skeleton of central routes for through traffic would not change much. The presented method can also be applied to other cities.     

一种改进条码尺编码的闸门开度测量方法

闸门开度测量是水工闸门监控最基本的指标之一,传统的闸门开度测量方法测量精度低、测量难度大。为解决测量闸门开度难题,本文研究了基于条码尺图像分析的闸门开度测量方法,针对三周期等间距条码尺编码的缺陷,提出了一种新的编码解码方式进行改进,并建立了一套完整的闸门开度测量检测系统。模拟闸门实时开度试验结果表明,本系统能够实时全自动测量闸门开度信息,测量精度高,稳定性强,表明改进后方法能够取得较好的闸门开度测量效果,为实际闸门开度工程测量提供了有效的解决思路。