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Zhang J.,China Academy of Railway Sciences | Zhang J.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Wang Y.,China Academy of Railway Sciences | Wang Y.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Jiang F.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation
Zhongguo Tiedao Kexue/China Railway Science | Year: 2011

FLUNENT software was used to simulate and analyze the sand flow field near the embankment of Lan-Xin Railway in gobi region. The results demonstrate that relatively low-speed areas occur at the slope foot of the windward side, near the embankment surface and at the slope foot of the leeward side, while relatively high-speed areas occur at the shoulder of windward side in the sand flow field around the embankment. Wind erosion occurs at the relatively high-speed area while, sand accretion happens at the relatively low-speed area and the sand accretion at the slope foot of the windward side is more serious than that on the leeward side. The numerical analyses of sand flow surrounding embankment with anti-sand walls of different height illustrate that the maximum wind regions shift from the shoulder of the windward side to the above of anti-sand walls. Meanwhile, the wind erosion at the shoulder of windward side is weakened. Most sand accretes in front of the anti-sand walls and sand crossing the walls falls down under the impact of the relatively low speed vortex areas between the anti-sand walls and embankment. The reasonable height of the anti-sand wall should meet the following requirements: firstly, most sand in the air flow should be blocked by the anti-sand wall. Secondly, no relatively high-speed area occurs at the shoulder of the windward side so as to avoid the strong wind erosion there. Thirdly, the boundary line of the high and low speed areas gets across the embankment surface steadily. Source


Wang X.,Zhejiang University | Wang X.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Mi W.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Wei Y.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Wu X.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

The change law, the morphological characteristics and the types of the artificial upper limits for the roadbeds of Qinghai-Tibet Railway in the permafrost region were analyzed based on the in-situ monitoring data of the ground temperature and the deformation for the rubble air-cooled roadbed with riprap slope protection, the rubble air-cooled roadbed, the roadbed of riprap slope protection, the roadbed with two-phase closed thermosyphon and the common roadbed. The results indicate that the shapes of the artificial upper limits for these roadbeds are divided into type A uplifting into the roadbed body and type B uplifting in the soil layer of the roadbed basement. And these changes fundamentally tend towards steady. The settlement of the roadbed also gradually tends towards steady as the time goes by. The accumulation settlement of the roadbed is in direct proportion to the roadbed height but is in inverse proportion to the rising value of the artificial upper limit. Source


Yang Y.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation | Jiang F.,Northwest Research Institute Ltd Company of China Railway Engineering Corporation
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

Combining with the tests of Qingshuihe experimental section of Qinghai-Tibet Railway, the temperature characteristics of the ventilated embankment have been studied. The validity of the ventilated embankment in the protection of permafrost has been analyzed according to the ventilation pipe embankment and the slope position within 1 m and the permafrost locations inside and outside the heat flow. The results show that the severe cold climate of Qinghai-Tibet Plateau has provided the environmental condition for the applicability of the vent-pipe. Embedding the vent-pipe in the embankment not only can increase the contact surface between the embankment and the air, but also can effectively prevent the going-down of the radiation heat absorbed by the roadbed surface through the strong convective activities of the plateau air to consume the heat in the embankment, which can protect the underlying permafrost to maintain the role of frozen state. As a new structure form in the permafrost regions of Qinghai-Tibet Plateau, the ventilated embankment has provided a favorable technical support for the construction and safe operation of Qinghai-Tibet Railway. Source

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