Experimental study on uplift behavior of shallow anchor plates in geogrid-reinforced soil

Geogrid reinforcement can significantly improve the uplift bearing capacity of anchor plates. However, the failure mechanism of anchor plates in reinforced soil and the contribution of geogrids need further investigation. This paper presents an experimental study on the anchor uplift behavior in geogrid-reinforced soil using particle image velocimetry (PIV) and the high-resolution optical frequency domain reflectometry (OFDR). A series of model tests were performed to identify the relationship between the failure mechanism and various factors, such as anchor embedment ratio, number of geogrid layers, and their location. The test results indicate that soil deformation and the uplift resistance of anchor plates are substantially influenced by anchor embedment ratio and location of geogrids, whereas the number of geogrid layers has limited influence. In reinforced soil, increasing the embedment ratio greatly improves the ultimate bearing capacities of anchor plates and affects the interlock between the soil and geogrids. As the embedment depth increases, the failure surfaces gradually change from a vertical slip surface to a bulb-shaped surface that is limited within the soil. The strain monitoring data shows that the deformations of geogrids are symmetrical, and the peak strains of geogrids can characterize the reinforcing effects.     

From natural environment to artificial system: Chang'an and its water system in the Western Han Dynasty

People around the world have shaped societies and urban spaces around water for millennia. They have transformed natural water structures and patterns to serve their diverse needs. The ways in which historical decisions affect contemporary water systems and influence future planning of urban systems still need to be fully recognized. This paper explores the multiple roles of water systems in Chang'an during the Western Han Dynasty. Chang’an, one of the ancient names for the city of Xi’an, was a typical capital city of China and East Asia in early ancient times. This study explores everyday practices pertaining to water as well as its role in defense, gardening, politics and culture.Drawing upon three historical theories, this study presents findings that water was embedded in the design of traditional Chinese capitals. The siting and construction of capital cities was first based on the Theory of Choosing the Center (3rd century BCE) and the Theory of Conforming to Nature (5th–3rd century BCE). However, the final maturation of this urban morphology, including the water system, was closely related to the Theory of Symbolizing and Modeling Heaven and Earth (4th–3rd century BCE), in a way that manifested the imperial power's organization and control of space and time.Through close analysis of historical documents, archaeological reports and modern investigations, the paper aims to clarify, analyze and summarize the historical context and evolution, functional and structural characteristics, as well as the economic, political, cultural and military connotations of water systems in Chang'an. It argues that the coordination of urban construction and the water environment was a key foundation for capital city development. It proposes that people shaped urban water supply in many ways, including daily life, waterway transportation, agricultural irrigation, aquaculture promotion, military defense and fire prevention.The water system in Chang'an also provided an important place for royalty and nobility to go fishing, to hunt and to engage in leisure and naval training. The landscape with this water system as the core, including Taiye Lake and Kunming Lake, had also inspired Chinese gardening history, and had a profound impact on future generations. More importantly, the capital's urban morphology design was a miniature of the world recognized by the monarch, as well as the symbolic image of the supreme rulers' political and cultural desire to control and possess Tianxia, which essentially means the whole world. In conclusion, the paper calls for a closer study of water-based design as a foundation for urban planning.     

Long term performance of recycled concrete beams with different water–cement ratio and recycled aggregate replacement rate

The purpose of this study is to reveal the service performance of recycled aggregate concrete (RAC) components for different values of water−cement ratio and replacement rate of recycled coarse aggregate (RCA). Generally, the concrete strength decreases with the increase of the replacement rate of RCA, in order to meet the strength requirements when changing the replacement rate of RCA, it is necessary to change the water−cement ratio at the same time. Therefore, the axial compressive strengths of prism with 25 mix proportions, the short-term mechanical properties and long-term deformation properties of reinforced concrete beams were tested respectively by changing water−cement ratio and RCA replacement rate. The bearing capacity and the strain nephogram of samples under different loads were obtained using the Digital Image Correlation (DIC) method, and a self-made gravity loading experimental device was used for long-term deformation investigation. Results showed that the damage pattern of RAC was the same as that of natural aggregate concrete (NAC), but the brittleness was more pronounced. The brittleness of concrete before failure can be reduced more effectively by adjusting the replacement rate of RCA than by adjusting the water−cement ratio. The water−cement ratio has an evident influence on the axial compressive strength and early creep of concrete, while the replacement rate of RCA has a remarkable effect on the long-term deformation of the concrete beams.     

基于卫星遥感影像的城市影像地图集编制

简要介绍以IKONOS卫星 1.0 m真彩色遥感影像为数据源编制<南京市区卫星影像地图集>的技术路线、作业方案、工艺流程以及编制要求.同时,结合目前国内外编制较好的城市影像地图集,对城市大比例尺遥感影像地图集的编制方案和编制理论等做一些初步探讨.     

古村落的文化解读及其文化意象塑造

对龙湖古寨进行文化解读,指出该寨具有独特的人居文化、海洋文化、科教文化和女性文化,在此基础上,通过选择祠堂、书斋等意象要素,塑造村落的文化意象,并提出古村落文化意象的塑造途径,为古村落的开发提供新的思路。     

“系统设计方法”在建筑设计中的运用——宁波双鹿金座项目创作有感

以宁波双鹿金座项目设计为例,运用＂系统设计方法＂从主楼形式、总体布局、建筑形体和平面功能分析入手,阐述了基于理性思考和感性认识的建筑创作过程。     

浅析城市新区规划中引入整体城市设计的目的及意义

以贵阳市金阳新区为例,分析了城市新区规划中引入整体城市设计的目的,说明了新区规划中引入整体城市设计的意义。     

图像增强在空三加密中的应用

针对摄影测量作业中,影像对的亮度不平衡,对比度低、图像模糊的情况,提出了在空三加密之前引入图像增强处理方法和处理流程,通过商用软件对原理和流程进行实现,并结合实际工程应用取得了良好的效果。     

桁梁局部破断试验中动位移的数字图像测量

将数字图像测量技术应用于桁梁结构局部破断试验中结构动位移的测量。对目标测点标记亮斑并布置对比度较强的背景,采用高清晰摄影机在结构破坏过程中采集图像,使用Matlab编制程序对目标点亮斑进行识别,计算其在图像中位置的变化并输出目标点位移曲线。试验结果显示,按该方法可获得符合实际的测点位移数据,具有较高的可行性;另经静载试验验证,可获得相对于破坏试验中较大位移而言可接受的精度。     

建筑设计在特定环境中的理性建构

从总体布局、平面布局、形体塑造和空间组织等方面阐述了建筑物如何在特定的输油管道站场的环境下进行理性建构,指出建筑的合理定位至关重要,应从环境、功能、形象等方面入手。