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221.
本文通过对比分析,采用主目标分析法,科学地确定中缅铁路的走向和路线,认为此线的选择是开拓西向南亚大市场的捷径新通道,同时也是兼顾滇西南经济发展的最佳决策. 相似文献
222.
刘争平 《中国地质灾害与防治学报》2008,19(1):59-62
石膏岩溶在我国分布比较少。青藏线雁石坪地区发育有石膏岩溶。2006年9月在青藏铁路雁石坪以南约20km处,铁路右路肩及路基边坡发生地表塌陷。文章首先分析了病害发育地段的工程地质条件,包括本段的岩溶发育情况。结合勘察,分析了路基发生病害的原因,提出石膏岩溶发育区的路基病害工程处理措施意见。 相似文献
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Simulations and analyses of train-induced ground vibrations in finite element models 总被引:2,自引:0,他引:2
Analyses of the actual vibration measurements and the results from the mathematical and numerical models have been performed in both the frequency and time domains. The conclusions from these analyses were that two-dimensional models could be used in order to study certain effects of train-induced ground vibrations, but that three-dimensional analyses are necessary to achieve a better simulation of the problem. All these analyses were linear elastic. It was, however, found in the three-dimensional analyses that relatively large shear strains existed in the embankment and in the soft soil layers just beneath the railway embankment. These shear strains were taken into consideration through iterative reduction of the shear modulus of the materials where large shear strains were calculated. 相似文献
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227.
Based on observed data from field-testing embankment of the Qinghai-Tibet Railway, ground-temperature controlling effect of duct-ventilated embankment is studied in this paper.The results show that ventilation ducts can effectively cool the soils surrounding the ducts of the embankment, and the heat budget of the ambient soils in a year shows as heat release. Temperature status of the permafrost below the embankment with ducts buried in the relatively high position is similar to that of the common embankment. The permafrost processes warming all along in the two freezing-thawing cycles when the embankment was constructed. However, the temperature of the frozen soils below the embankment, in which the ducts buried in the relatively low position, rises a little in the initial stage. After that, it cools down gradually. At the same time,ventilation ducts can effectively reduce the thermal disturbance caused by the filled soils. The frozen soils below the common embankment and that with high-posited ducts absorb heat all along in the initial two cycles. While the soils below the embankment with low-posited ducts begin to release heat in the second cycle. This phenomenon proves that the ventilation embankment with low-posited ducts shows efficient temperature-controlling effect. Such embankment can actively cool the subgrade soils and therefore keeps the roadbed thermally stable. 相似文献
228.
Hu Zeyong CHENG Guodong QIAN Zeyu WANG Jiemin Wei Guoan HOU Xuhong GU Lianglei YAN Yuping 《中国科学D辑(英文版)》2004,47(Z1)
The data obtained through the roadbed surface thermal regime experiment (ROBSTREX), which was carried out at Beiluhe test section of Qinghai-Tibetan Railway from October to December in 2002, were used to estimate the cooling effect of ballast revetment on the roadbed. The results show that both riprap rock ballast revetment and crushed stone ballast revetment can reduce the temperature of the roadbed. But the cooling effect of riprap rock ballast revetment is better than that of crushed stone ballast revetment when the temperature of roadbed is higher. The cooling effect of crushed stone ballast revetment is better than that of riprap rock ballast revetment when the temperature of the roadbed is lower, especially at deeper roadbed layers. In the frozen season, the heat release from the roadbed also shows that the cooling effect of ballast revetment on the roadbed is obvious, and the cooling effect of crushed stone-ballast revetment on the roadbed is much evident than that of riprap rock ballast revetment. 相似文献
229.
保温材料在青藏铁路路基工程中应用的数值分析 总被引:1,自引:0,他引:1
In many cases, preventing permafrost from further thaw due to human activities might be the first choice for embankment design in permafrost regions. 2-D finite element analysis was conducted in this paper, in which phase change was taken into consideration to simulate the thermal regime of the Qinghai-Tibetan Railway with Expandable Polystyrene (EPS). Based on the predicted maximum thaw depth in the following 50 year, the best position for insulation was presented and the relationship between the thickness of insulation and the height of embankment was analyzed. Besides, the applicable range of insulation in embankment engineering of the Qinghai-Tibetan Railway in terms of Mean Annual Air Temperature (MAAT) was suggested and the influence of geothermal field of permafrost on the applicable range of the insulation was discussed. 相似文献
230.
The paper features the results of field measurements and numerical research of embankment behaviour in permafrost soils of Transbaikalia railway section following implementation of preventive works to eliminate action of heaving forces on the main area of embankment subgrade. 相似文献