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1.
David L. Dilcher 《世界地质(英文版)》2005,8(1)
It is my profound pleasure to be here today as an honored guest of the opening ceremonies for the Inauguration of Sino-German Joint Group of Paleontology and Geosciences. 相似文献
2.
David L. Dilcher 《东北亚地学研究》2005,8(1):147-147
It is my profound pleasure to be here today as an honored guest of the opening ceremonies for the Inauguration of Sino-German Joint Group of Paleontology and Geosciences. I stand before you as a member of the National Academy of Sciences of the United States of America, as a Graduate Research Professor of the University of Florida, as an Honorary Professor of Jilin University, as an Honorary Member of the Senckenberg Museum of Natural History, as a Friend of Tuebingen University, 相似文献
3.
Land bridge transportation means transportation from one seaport to another by railway across continents instead of by ocean ship. At present, there are two common routes for using land bridge transportation in the world. One is Asia-America-Europe land bridge, the other is Europe-Asia land bridge.Eurasia land bridge has obvious advantages over Asia-America-Europe land bridge due to its shorter distance, shorter transportation time and special freight rate. China started Eurasia land bridge transportation business in 1980. It mainly used the mode of railway-railway combined transportation. The comparison between using Eurasia land bridge and using shipping transportation from China to Northern and Western Europe shows that Euraria land bridge transportation can save time and get foreign exchange in time, and commodity turnover will be speeded up. According to the port layout and railway network structure, China's land bridge transportation projects are proposed. They are Suifenhe project, Dalian project 相似文献
4.
周绍元 《成都信息工程学院学报》2003,18(4):417-423
在惠斯通电桥原理电路的基础上，讨论了教学实验中自组电桥测量电路的仪器选择，举例分析了自组电桥测量电路的使用和测量结果，指出不同自组电桥测量电路在教学应用中的优点，为实验教学中突出教学重点而选择电路提供参考。 相似文献
5.
Debris flows are typical two-phase flows, which commonly accompany erosion in mountainous areas, and may destroy bridge engineering by scouring. In this study, a physically-based two-phase model is applied for the simulation of debris flow scouring of bridge pier. In this model, the shear stress of debris flow on an erodible bed is considered to be a function of the solid shear stress, fluid shear stress, and volume fraction; accordingly, the erosion is incorporated into the two-phase model. Using a highaccuracy computational scheme based on the finite volume method, the model is employed for simulating a dynamic debris flow over an erodible bed. The numerical results are consistent with the experimental data, and verify the feasibility of the two-phase model. Moreover, a simple numerical test is performed to exhibit the fundamental behaviour of debris flow scouring of bridge pier, which shows that the degree of erosion on each side of the pier is higher compared to other areas. The scouring depth is influenced by the variations of solid volume fraction and velocity of debris flow and pier width. 相似文献
6.
In the current theory of bridge foundation design,all of the loads above the cap are loaded by the pile,and the bearing capacity of the soil among piles is not taken into account.In order to analyze the bearing capacity of the soil among piles in bridge pile foundation,a model of pile foundation is established based on a bridge foundation which is under construction,and by the finite element analysis software ANSYS.According to the results of finite element analysis(FEA)and current bridge foundation design theory,a feasible composite pile foundation which can be applied in the design of bridge foundation,is recommended.Additionally,a number of modifications are made to the original design.It was confirmed that these modifications derived from numerical simulations can improve the performance of the foundation. 相似文献
7.
Finite element analysis on impact of foundation treatment in bridgehead transition section upon bridge piles 
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下载免费PDF全文 In order to decrease relative settlement, foundation treatment plays an extremely important role in bridgehead transition section, especially, the situation of building the bridge piles firstly, and th... 相似文献
8.
Linear monitoring is an important link of bridge construction control,which is conducted in key processes of construction to ensure the security of bridge in construction procedure. Combining with main arch construction monitoring program of No. 2 bridge in north district of Changbai international tourism resort,main content and key technologies are recommended. Considering the various influential factors during the construction process,linear adjustment is handled to ensure that the stress and linear of main arch meet design requirements. 相似文献
9.
《山地科学学报》2021,(8)
A tunnel-type anchorage(TTA) is one of the main components in suspension bridges: the bearing mechanism is a key problem. Investigating the deformation characteristics, development law, and failure phenomenon of a TTA under load can provide the theoretical basis for a robust design. Utilizing the TTA of the Jinsha River suspension bridge at Lijiang Shangri-La railway as a prototype, a laboratory model test of the TTA was carried out for three different contact conditions between the anchorage body and the surrounding rock. The stress and deformation distribution law of the anchorage body and its surrounding rock were studied, and the ultimate bearing capacity and failure mode of the TTA were analyzed. The test results show that the compressive stress level is highest at the rear part of the anchorage body. Moving away from the rear portion of the body, the stress decays in a negative exponential function. Based on the load transfer curve, the calculation formula for the shear stress on the contact surface between the anchorage body and the surrounding rock was derived, which shows that the distribution of the shear stress along the axial direction of the anchorage body is not uniform. The distance from the maximum value to the loading surface is approximately 1/3 of the length of the anchorage body, and the stress decreases as the distance from the loading surface increases. Furthermore, the contact condition between the anchorage body and surrounding rock has a great influence on the bearing capacity of the TTA. The increase in the anti-skid tooth ridge and radial anchor bolt can improve the cooperative working capacity of the anchorage body and the surrounding rock, which is approximately 50% higher than that of the flat contact condition. The main function of the anchor bolt is to increase the overall rigidity of the TTA. The contact condition between the anchorage body and the surrounding rock will lead to a change in the failure mode of the TTA. With an increase in the degree of contact, the failure mode will change from shear sliding along the interface to trumpet-shaped inverted cone-shaped failure extending into the surrounding rock. 相似文献
10.
国道108线K9+69410沙河立交小桥地基采用高压旋喷注浆法加固.系统介绍了工程概况、设计方案、注浆施工,并通过现场试验证明了高压旋喷注浆法加固桥梁地基是一项成功实践. 相似文献
11.
The Sichuan-Tibet transportation corridor is prone to numerous active faults and frequent strong earthquakes. While extensive studies have individually explored the effect of active faults and strong earthquakes on different engineering structures, their combined effect remains unclear. This research employed multiple physical model tests to investigate the dynamic response of various engineering structures, including tunnels, bridges, and embankments, under the simultaneous influence of cumulat... 相似文献
12.
Xiaopei ZHANG Jianhui QIU Jianjun NIU Lizhi DU Xuege WANG .College of Construction Engineering Jilin university Changchun China.China Northeast Municipal Engineering Design Research Institute Changchun China 《东北亚地学研究》2008,11(4):218-221
The ultrasonic computed tomography （USCT） method is derived from the basic principles of X-ray section scanning. This method records the arriving times of ultrasonic wave between the probes and the sources to ealculate the elastic wave velocity values in the section using the arrival times. Through analyzed the distribution Of elastic wave velocity in aim area, the information of the strength and the homogeneity of the investigated zone could be got indirectly. The authors introduced the operational principle of USCT and a practical case of using this method to detect the interior defects in large scale concrete structural member. Compared with other exploration methods, this method is more efficient and accurate. 相似文献
13.
The ultrasonic computed tomography (USCT) method is derived from the basic principles of X-ray section scanning. This method records the arriving times of ultrasonic wave between the probes and the sources to calculate the elastic wave velocity values in the section using the arrival times. Through analyzed the distribution of elastic wave velocity in aim area, the information of the strength and the homogeneity of the investigated zone could be got indirectly. The authors introduced the operational principle of USCT and a practical case of using this method to detect the interior defects in large scale concrete structural member. Compared with other exploration methods, this method is more efficient and accurate. 相似文献
14.
This paper systematically analyzes and proves the favorable factors of utilizing the ports and the railways in Northeast China for the Asia-Europe land bridge transportation. It will be more beneficial to Dalian Port and HaDa (Harbin-Dalian) and Binzhou (Harbin-Manzhouli) railways in Northeast China to the Siberia railway in Russia than 1) to other ports and the corresponding railways in China, 2) to the Nakhodka Port in Russia and the corresponding railways and 3) to the Chongjin Port in North Korea and the corresponding railways. This paper also puts forward the reform measures to adopt the ports and the railways in the northeast region in China for the land bridge transportation and the problems in transportation policies and management systems. 相似文献
15.
Ricardo OLIVEIRA 《山地科学学报》2011,8(2):296-306
The safety of large structures requires adequate foundations, which implies a good knowledge of the geological and geotechnical conditions of the respective ground. In general, that is only possible through engineering geological studies which include proper site investigation techniques, adapted to the nature of the ground (rock mass or soil) and to the associated engineering problems. The paper illustrates the studies carried out for the design of the foundations of Ribeiradio 76 m high concrete gravity dam in a difficult rock mass and of Vasco da Gama Bridge, 13 km long, crossing the Tagus River in Lisbon, Portugal, through piles 75 m deep. 相似文献
16.
业务过程建模是整个工作流管理系统的基础,选择一种高效的建模技术对复杂多变的实际业务流程进行形式化表示,对构建一个灵活的工作流管理系统起着至关重要的作用.文章论述了Petri网理论和工作流技术,探索了Petri网和工作流技术相结合的优势和可行性,讨论了如何运用Petri网理论实现工作流管理系统部件--过程定义工具的分析功能,然后给出了一个具体高速公路应急处置流程的基于Petri网建模方式的实例. 相似文献
17.
为探究济南市玉符河人工补源对趵突泉泉域的影响,在系统分析泉域水文地质条件的基础上,采用地下水数值模拟软件GMS10.0建立了2012—2014年覆盖趵突泉泉域的地下水流数值模型,通过模型对玉符河补源实施后地下水的径流方向、影响面积以及对泉水位和西郊水源地水位的提升作用进行评估。结果表明:玉符河补源在实际渗漏量为10.52×10~4m~3/d的情况下,玉符河补源水首先沿着炒米店地堑由南向北流,然后再向东、西方向径流。补源后第177 d,补源影响范围基本抵达四大泉群,玉符河补源的最大影响范围为485.79 km~2。玉符河补源对趵突泉、黑虎泉的最大影响水位为0.06 m和0.04 m;对济南西郊水源地的水位起到明显的提升作用,最大值达到0.57m。西郊水位的抬升可以缓解地下水开采对趵突泉水位的影响,减小保泉的压力,也为将来济南百姓重新喝上优质地下水奠定了基础。 相似文献
18.
世界贸易组织从2002年启动渔业补贴谈判以来,共进行了近40轮谈判。在谈判期间,渔业补贴的调整范围、规范模式、执行问题以及发展中国家特殊与差别待遇成为成员之间争论的焦点。 相似文献
19.
基于GIS的地质灾害易发区划分与评价研究 总被引：1，自引：0，他引：1
分析了地质灾害形成条件、诱发因素,将灾点分布密度、斜坡坡度、斜坡坡型、斜坡坡高、河流冲刷、岩土体条件、人类活动等七个因素作为地质灾害易发程度评价指标,利用层次分析法计算出各评价因子的权重。基于GIS将评价因子进行量化,得到了各评价指标归一化图,根据各评价指标的权重,利用空间叠置分析功能将所有评价指标进行叠加分析计算,得到地质灾害高易发区、中易发区、低易发区和不易发区的分级结果。分级结果极大地方便了地方政府相关部门防灾减灾工作,为地质灾害防治提供了决策依据。 相似文献
20.
针对目前重力探测中重力改正时常用的两个高程参考系统存在偏差这一事实,选取两个大地水准面起伏变化较大的剖面区域,分析大地水准面起伏对重力归算的影响。结果表明,剖面跨度和剖面大地水准面起伏梯度都会对布格重力异常产生影响,所以当重力探测区域大地水准面起伏差距较大时,大地水准面与参考椭球面之间的差异对重力归算的影响比较突出,在利用布格重力异常反演、解释地壳密度结构时,大地水准面起伏的影响必须考虑。 相似文献