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Peng N.,Lanzhou University | Yan Z.,Lanzhou University | Sun B.,Northwest Research Institute Co. of China Railway Engineering Corporation | Gao L.,Lanzhou University
AIP Conference Proceedings | Year: 2013

The Yungang Grottoes are one of most famous ancient Chinese Buddhist temple grottoes in the province of Shanxi. To preserve the grottoes against the earthquake which is one of the most important factors leading to damage of the grottoes, a 3-D finite element dynamic model of the 19th grotto's west ear-grotto is built to explore its dynamic responses under earthquakes. The simulation results show the cliff has a tendency to dump, and the distribution of final state displacement on thin rock mass between grottoes is rhythmical. Larger acceleration plays a decisive role in the displacement responses. The maximal peak ground acceleration (PGA) amplification factor could reach ∼ 130. The rock mass ranging from the roof of ear-grotto to the top rock mass absorbs most of the energy and is the most dangerous region where collapse often happens. © 2013 AIP Publishing LLC.

Li M.,Xian University of Science and Technology | Zheng J.,Northwest Research Institute Co. of China Railway Engineering Corporation
Journal of Railway Engineering Society | Year: 2013

Research purposes: The secondary hazards of the slope happen continuously after the Wenchuan earthquake and they cause big losses. In order to provide theoretical guidance for prevention and reduction of the earthquake disaster, the study was done on the slope disease type, the slope characteristics and the distribution and scale of the slope disease based on the investigation of the slope disease along the Wenchuan-Yingxiu section of the Dujiangyang-Wenchuan Highway, the Chengdu-Guangyuan section of the Baoji-Chengdu Railway and the Chengdu-Kunming Railway. Research conclusions: (1)The 97 slope diseases of six categories were found in the investigated area. Among these diseases, the slide was the serious disease, followed by the landslide and the collapse while there was a little dehris and seldom scattered. The rockfall was common, but its scale was small. (2)The medium loose and broken slope at the higher altitude was generally the potential disease-prone slope. (3)With earthquake effect, the damage degree of slope gradually weakened from the epicenter to the perimeter, it meaned the epicenter was the heavy disaster area, and the slope disease damage gradually decreased with increase of the distance to epicenter. (4)The research results can be used in preventing secondary slope disaster in earthquake disaster areas.

Li Y.-Q.,Northwest Research Institute Co. of China Railway Engineering Corporation
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

Thermal probes, a device to exchange heat with air and liquor convert, have characteristics of no engine loss and highly decreasing earth temperature around the thermal probes. The thermal probes have obvious effects for decreasing earth temperature under the foundation, increasing cold storage of earth foundation and protecting permafrost. It is a simple and suitable engineering measure for protecting permafrost. Now it has been widely used in Qinghai-Tibet Railway in permafrost area. In view of application of the thermal probes in the civil engineering, many researches in China and foreign countries are carried out. Many key technologies of thermal probes are solved, for example, making crafts, trail of model in low temperature, design and calculation and so on. But there are not any father researches on the relation among diameter of thermal probes, effect of decreasing earth temperature and producing cold quantity. In order to solve this kind of problems, a series of experiments in permafrost region along the Qinghai-Tibet Railway are performed. The test content includes three thermal probes with the same length but different diameters in Anduo experimental section. In given conditions, within certain range of diameter of thermal probes, the results show: (1) its producing cold quantity doesn't increase with the increase of the diameter; (2) there seems to be the same decreasing earth temperature and producing cold quantity with different diameters; (3) after comprehensive consideration, the optimal diameter of thermal probes is 89 mm.

Liu S.-F.,Northwest Research Institute Co. of China Railway Engineering Corporation
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2011

With the rapid development of basic communication construction in China, basic road construction is steadily increasing. The miles of roads increase and the grade of roads goes higher. In order to raise transport speed and efficiency, the line selection and road construction gradually extend from plain areas to hilly and mountainous areas, and consequently the problem of slope disasters is increasing. A brief introduction of roadbed diseases in Huangnan district of Qinghai Province is given. In a case study, the distribution of disease area, characteristics of deformation, causes of diseases, scale of diseases, tendency of disease development, degree of dangerousness and hazard extent are analyzed and studied. After a comprehensive analysis of the causes of deformation, the corresponding control measures are presented and are proved to be effective.

Wu X.-P.,Lanzhou University | Wu X.-P.,Northwest Research Institute Co. of China Railway Engineering Corporation | Xiong Z.-W.,Northwest Research Institute Co. of China Railway Engineering Corporation | Wang X.-J.,Zhejiang University | Qu Y.-H.,Northwest Research Institute Co. of China Railway Engineering Corporation
Yantu Lixue/Rock and Soil Mechanics | Year: 2012

This paper makes a study of the collapsible characteristics under overburden pressure of the Western Henan loess along Zhengzhou-Xi'an high-speed railway by field experiment. The developing process in the depth of loess collapsibility under overburden pressure and the collapsible horizontal distance have also been analyzed. The results show that: the influence of soaking boundary on collapse is very clear; but collapsible rate shows a slow-fast-slow-until-stable tendency, with 60% of the total settlement immersed for 10 days and 90% for 30 days. The β 0 of the site is 1.30, greater than the recommended 0.9 by the code. The results show that the extent of collapsibility of this region is more intense than that of general knowledge. In the site, loess collapse under overburden pressure maximum depth laboratory test value is 19 m; and field test value is 16 m, the former is 1.2 times the latter. The collapsible horizontal distance out of the test pit is 20 m, similar with the diameter of the test pit. Therefore, no water should be kept within 20 m from the embankment toe. The research results have been applied to the Zhengzhou-Xi'an high-speed railway construction, and can be taken as reference for similar projects in this region.

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