基于堆积层厚度变化的侏罗系顺向岸坡变形机制转换研究

三峡库区侏罗系顺向岸坡堆积体滑坡众多,其滑动模式存在一定差异。首先统计分析了192个三峡库区侏罗系层位发育的堆积体滑坡滑体及碎石土的工程地质性质和强度参数。在此基础上,运用数值分析软件对堆积体厚度变化引起的滑坡变形机制进行模拟分析。结果表明:堆积体厚度范围在15m及以下滑坡会沿着岩土界线面滑动、15~35m时滑坡会沿着层内剪切面滑动;厚度范围在35m以上时,堆积体滑坡内部可能存在着多层滑带,即滑坡可能沿着层内剪切面滑动或者沿着岩土界线面滑动。堆积体厚度范围在15m及以下时滑坡的治理措施可采用布置抗滑桩;厚度范围15~35m时可采用排水+布置抗滑桩的滑坡治理措施;厚度范围在35m以上时,可采用滑坡前期监测预报+后期根据滑坡发育情况相结合的滑坡防治措施。     

秋季南黄海浮游动物分布及其影响因素

基于2007年秋季在南黄海（32°20'~37°00'N;124°E以西）进行的浮游动物及环境因子大面调查;分析了秋季南黄海浮游动物种类组成、分布特征及其影响因素;主要结果如下:共鉴定浮游动物113种（不包括25种浮游幼体）;中华哲水蚤（Calanus sinicus）、强壮滨箭虫（Aidanosagitta crassa）、磷虾幼体（Euphausia larvae）和小齿海樽（Doliolum denticulatum）是秋季优势种;浮游动物丰度为（156.37±12.04）ind/m3;生物量为（172.57±10.41）mg/m3;与历史调查数据相比;本航次浮游动物丰度和生物量相对处于较高水平;磷虾幼体分布趋势与中华假磷虾（Psudeuphausia sinica）一致;说明秋季是中华假磷虾种群的一个重要的补充时期;小齿海樽在南黄海的大量出现系自身种群补充的结果;精致真刺水蚤（Euchaeta concinna）和肥胖软箭虫（Flaccisagitta enflata）主要分布在深水区;在近岸海区很少出现。中华哲水蚤、强壮滨箭虫丰度高值区倾向分布于海洋锋附近;进一步佐证了海洋锋对浮游动物的积聚作用。     

Determination of shear strength of conglomerates using a caterpillar D9 ripper and comparison with alternative methods

Summary A method of determining shear strength in Gila Conglomerates at Inspiration Mine (now Cyprus Miami Mine), Arizona, using Caterpillar D9H and D9L rippers is described. The results are compared with data obtained using laboratory direct shear tests — both large and small scale, back analysis and boulder modelling. The significance of scale, particularly relating to boulder size is discussed.     

Towards a direct collapse–load method of design for concrete frames subjected to severe ground motions

Most current methods of design for concrete structures under earthquake loads rely on highly idealized ‘equivalent’ static representations of the seismic loads and linear‐elastic methods of structural analysis. With the continuing development of non‐linear methods of dynamic analysis for the overload behaviour and collapse of complete concrete structures, a more direct and more accurate design procedure becomes possible which considers conditions at system collapse. This paper describes an evaluation procedure that uses non‐linear dynamic collapse–load analysis together with global safety coefficients. A back‐calibration procedure for evaluating the global safety coefficients is also described. The aim of this paper is to open up discussion of alternative methods of design with improved accuracy which are necessary to move towards a direct collapse–load method of design. Copyright © 2002 John Wiley & Sons, Ltd.     

南京市老城区城市建筑点格局研究

城市建筑是城市形态的重要组成部分,而建筑高度对城市三维空间形态有重要的影响。目前,对城市二维形态的研究较为丰富,而对城市三维起伏形态特征及其空间分布格局方面研究较少,对城市上空利用程度及发展规律认识仍相对缺乏。本文以南京市老城区为例,基于城市数字高程模型数据,将城市建筑抽象为三维点要素,运用点格局分析法研究城市建筑三维宏观特征及建筑类型的空间分布规律。结果显示：（1）南京老城区建筑呈集聚分布,聚集性顺序是低层建筑>高层建筑>多层建筑>超高层建筑。除超高层建筑外,低层、多层和高层建筑的聚集程度,随着空间尺度先增后减,均在1.5 km尺度聚集性最大;显示1.5 km的街区单元应是城市规划管理的最适宜单元。（2）南京老城区建筑高度空间分布表现为“三高一低”,即3个高值区（新模范马路、新街口和珠江路区域）和1个低值区（集庆门区域）,它们与不同时期城市中心具有较好的对应关系;不同类型建筑与城市基准地价的相关分析显示,建筑高度的分布与城市基准地价呈现一定相关性。结果表明,点格局分析方法能有效地分析城市建筑在平面及三维的空间格局特征,进一步深化对城市形态特征的认识。     

近50 a来杭州湾冲淤变化规律与机制研究

使用杭州湾1959-2010年的水下地形图, 结合过去数十年来长江入海水沙量和钱塘江河口段冲淤变化状况, 分析了近50 a来杭州湾在长江入海泥沙量锐减和治江围涂等人类活动作用下的冲淤变化规律及其物理机理。结果表明, 乍浦以上区域近50 a来处于较显著的淤积状态, 且有自上向下发展的趋势, 这种淤积主要是由于钱塘江河口治江缩窄工程所引起的;湾内地形发生了局部调整, 部分小型潮流槽脊系统趋于消亡, 地形趋于平坦化, 湾口北部2003年以后有转淤为冲的趋势, 这与长江入海泥沙量锐减和该区域围垦工程等因素有关;1959-2003和2003-2010年两个时段, 湾内泥沙淤积的年平均值分别为0.91×108和1.66×108 m3。对于整个钱塘江河口系统而言, 即自杭州湾湾口至钱塘江河口段的闸口断面, 长江入海泥沙量减少所产生的影响尚不明显, 2003年以后泥沙淤积速率甚至有所上升。杭州湾近50 a的冲淤变化是人为强烈干预下的大流域-河口系统响应与中小流域-河口系统响应的调整结果。     

模拟水深测量实习设计与实现

针对海洋测绘实践教学中,水深测量实习受场地、经费和安全因素影响大,难以开展的问题,设计并实现了模拟水深测量实习。该模拟实习能较为真实地模拟了水深测量的主要步骤,易于开展和推广。     

Ecologically based landscape pattern optimization in northwest of Beijing

Supported by the technologies of remote sensing (RS) and geographical information system (GIS), we chose northwest of Beijing as a study area and gave priority to understanding of the spatial-temporal characteristics of landscape pattern change through visually interpreted Landsat TM images of 1989, 1996 and 2005. It is believed that there were a series of landscape ecological problems caused by city expansion: landscape ecological connectivity was low; landscape structure was simplified; the fragmentation of green land patch was more obvious on the plain areas, moreover, spatial distribution of green land was unbalanced. For this reason, this study adopted accumulative cost distance model, combined with ecosystem services and spatial interactions of landscape types, analyzed the spatial difference of the ecological function and the compactness of landscape structure in the study area, and further discussed the landscape pattern optimization proposal. We find that it is essential to protect and establish ecological sources, to establish urban ecological corridors, and to establish ecological nodes at the landscape ecological strategic positions so as to intensify spatial relationships among landscape elements and maintain continuity of landscape ecological process and pattern in the course of city expansion. The methods and final results from this study are expected to be useful for landscape ecological planning in Beijing region.     

尼日尔盆地油藏水道沉积构型识别及演化规律

深海水道作为深水环境中重要的储层类型,具有极为丰富的深海油气资源,近年来一直是深海油田勘探和开发的重点区域,但对水道内部构型边界的识别刻画仍然是一个难点。依据三维地震数据以及测井和岩心资料,对西非X油藏水道进行了内部构型边界的精细划分,并分析了其水道演化模式。研究表明：区内水道体系边界可通过地震相特征差异进行识别,并将其分为限制性、半限制性和非限制性3种类型;复合水道边界可通过“垂向分期”和“侧向划界”原则进行确定;单一水道边界可通过水道边界振幅强弱变化进行识别,其在平面上有单侧向迁移和沿下游摆动迁移2种迁移模式,在剖面上单向侧向迁移段水道呈侧向迁移的特征,沿下游摆动段呈现出多期水道相互摆动切叠的特征;水道体系的演化可划分为初始形成、快速发育、平稳发育以及水道消亡4个阶段,对应一个完整的海平面变化旋回。     

Damage investigation of girder bridges under the Wenchuan earthquake and corresponding seismic design recommendations

An investigation of girder bridges on National Highway 213 and the Doujiangyan-Wenchuan expressway after the Wenchuan earthquake showed that typical types of damage included： span collapses due to unseating at expansion joints; shear key failure; and damage of the expansion joint due to the slide-induced large relative displacement between the bottom of the girder and the top of the laminated-rubber bearing. This slide, however, can actually act as a form of isolation for the substructure, and as a result, the piers and foundation of most of the bridges on state route 213 suffered minor damage. The exception was the Baihua Bridge, which suffered severe damage. Corresponding seismic design recommendations are presented based on this investigation.