Title Using perforated ventilation ducts to enhance the cooling effect of crushed-rock interlayer on embankments in permafrost regions
Author Dong Yuanhong; Lai Yuanming; Xu Xiangtian; Zhang Shimin
Author Affil Dong Yuanhong, Chinese Academy of Sciences, Cold and Arid Regions Environmental and Engineering Research Institute, State Key Laboratory of Frozen Soil Engineering, Lanzhou, China
Source Cold Regions Science and Technology, 62(1), p.76-82, . Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0165- 232X
Publication Date Jun. 2010
Notes In English. Based on Publisher- supplied data GeoRef Acc. No: 309553
Index Terms construction materials; convection; cooling; design; embankments; permafrost; temperature; tests; ventilation; crushed stone; roads; testing
Abstract A previous laboratory test carried out by the authors proved that the addition of ventilation ducts can efficiently enhance the cooling effect of crushed-rock interlayer. The mechanism revealed by the laboratory test was that, the ventilation ducts intensified natural convection and thus enhanced cooling effect of the crushed-rock interlayer by decreasing its upper boundary temperature. In this study, to further enhance the cooling effect of the crushed-rock interlayer, the ventilation ducts were perforated and then positioned at the upper boundary of the crushed-rock interlayer. Two crushed-rock interlayer embankments with perforated and imperforated (ordinary) ventilation ducts were tested under the same test conditions. The analysis of the temperature characteristics of the two test crushed-rock interlayer embankments with perforated and imperforated ventilation ducts showed that the crushed-rock interlayer embankment performed a more efficient cooling effect when the ventilation ducts were perforated. The effect was straightforward: the addition of the perforation on the ventilation duct wall let the air that was flowing through ventilation ducts partially penetrated into the crushed-rock interlayer. The result was that, during negative air temperature period, the upper boundary temperature of crushed- rock interlayer was decreased to a great extent, and consequently natural convection in the crushed-rock interlayer was intensified. The cooling effect during negative air temperature was efficient enough to restrict the heat injected into the embankment during positive air temperature period. On the whole, the crushed-rock interlayer embankment with perforated ventilation ducts has a good cooling effect to the underlying permafrost. Based on these, the new type of embankment is recommended in the construction of large-width highways in permafrost regions in the future.
URL http://hdl.handle.net/10.1016/j.coldregions.2010.03.003
Publication Type journal article
Record ID 65006554