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171.
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This paper's primary purpose is to compare the 2D and 3D analysis methodologies in investigating the performance of a concrete faced rock‐fill dams under dynamic loading conditions. The state of stress on the face plate was obtained in both cases using a total strain based crack model to predict the spreading of cracks on the plate and the corresponding crack widths. Results of the 2D and 3D analyses agree well. Although significantly more demanding, 3D analyses have the advantage of predicting the following: (i) the opening of the vertical construction joints; (ii) the cracking at the valley sides; and (iii) the crushing of the plate during the seismic action. During the earthquake loading, the cracking predicted at the base of the face plate after the impounding spread significantly towards the crest of the dam; however, the crack widths are obtained relatively small. Crushing of the face plates at the construction joints is the primary cause of the large scale cracking predicted on the face plate for high intensity earthquakes. Earthquake induced permanent deformation of the fill increases the compressive stresses on the face plate, thereby reducing the minute cracking on the plate. However, this effect also leads to significant increases in the residual openings at the construction joints and at the plinth level. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
173.
Analyzing Effects of Shrub Canopy on Throughfall and Phreatic Water Using Water Isotopes,Western China 总被引:1,自引:0,他引:1
Alpine shrub Quercus aquifolioides was selected to study the effects of shrub canopy on throughfall and phreatic water by analyzing the isotopic time series of precipitation, canopy throughfall and phreatic water and examining correlations among these series in Wolong Nature Reserve, Western China. Based on analysis of precipitation data in 2003, the local meteoric water line during the rainy season was δD = 8.28 × δ18O + 8.93, and the primary precipitation moisture in this region originated from the Pacific Ocean in the summer. Stable isotope analysis showed that the main supply of throughfall and phreatic water was from precipitation, and the shrub canopy has an important effect on the processes of rainwater transmuted into throughfall and phreatic water. Moreover, the differences of δD and δ18O values between rainwater and throughfall were relevant to rainfall. Due to interception of the shrub canopy, there had a response hysteresis of phreatic water to the various rainfall events, which was mostly 2 days, except that this hysteresis was ≤1 day when rainfall was >15 mm/day. 相似文献
174.
《Urban geography》2013,34(2):162-184
Port competition at both the regional and global scales results in port concentration and deconcentration, respectively. Whereas a number of recent studies interpret such phenomena as the effects of global forces such as containerization, few researchers have investigated local forces, such as the evolving relationships between urban policy and port growth. This study compares how two global hub port cities in the Asia-Pacific region, Hong Kong and Singapore, have sustained their port functions while transforming into major economic centers. Entropy indexes are calculated by district based on service industries related to port activities between 1993 and 2004. The results show the influences of port competition, lack of space, and congestion on changes in port-related activities. We conclude that cross-border integration is a main differentiating factor in the evolution of these hub port cities. 相似文献
175.
以地图符号形式表达地理要素是GIS地理信息可视化的有效手段.目前Web GIS发布系统在复杂地图符号的表达能力、地图的快速发布和运行效率等方面存在一定的不足.为此,应用IE浏览器内容扩展技术,结合地图符号表达的特征,设计出面向基础地理数据的地图浏览服务器,给出地理数据类型可兼容的快速发布矢量地图文档结构.据此,开发基于... 相似文献
176.
高苏新 《测绘与空间地理信息》2011,34(3):24-26
结合苏州市地理信息系统平台建设实际情况,分别从建设目标、技术设计,系统开发、共享模式和应用推广等方面总结了数字苏州市公共服务平台建设的思路与经验,同时也提出了当前推广地理信息系统应用集成开发的创新思想. 相似文献
177.
基于振动台的动力子结构试验界面反力获取方法 总被引:2,自引:0,他引:2
基于振动台的实时子结构动力试验是一种新型的结构动力试验方法.该试验方法引入了“子结构”这一概念,不仅减小了常规振动台试验对于试验规模的限制,而且克服了拟动力子结构试验中无法考虑加载速率影响的问题.由于该试验方法将整体结构拆分为数值子结构和物理子结构两部分,二者之间通过交界面相互作用力实现实时数据交互,以保证子结构体系与... 相似文献
178.
在对油水接触面形态和油水过渡带厚度的分布规律进行定量分析的基础上,以苏北盆地花17断块为例,结合油井生产动态特征分析了构造-岩性油藏中油水分布规律,并探讨了其影响因素.结果表明,在实际油藏中油水接触面是一个呈波状起伏的面,其在自由水面以上的高度随残余油饱和度下的毛管压力增大而抬高;油水过渡带厚度仅与束缚水饱和度和残余油... 相似文献
179.
本文将岩石视为颗粒体材料,采用两种模型对巷道围岩的应力、应变及破坏区的分布规律进行了数值模拟。第一种模型是连续介质模型,其中考虑了颗粒、界面及基体。第二种模型是将第一种模型中的基体去掉。研究结果表明:当基体强度参数降低较少时,巷道围岩中的环向和径向应力在传统结果附近波动;当基体强度参数降低较多时,两种应力的波动幅度提高,而且,基体位置的应力向其周围的颗粒或界面转移。第二种模型结果的波动幅度更大。随着基体强度参数的降低,巷道围岩中的应变集中区向深部转移,形成相互交织的滑移线网,滑移线网的位置主要位于基体和界面中,这与第二种模型的结果有明显的差异(多个环向的应变集中区)。 相似文献
180.