Title The thermal effect of differential solar exposure on embankments along the Qinghai-Tibet Railway
Author Wu Qingbai; Liu Yongzhi; Hu Zeyong
Author Affil Wu Qingbai, Chinese Academy of Science, Cold and Arid Regions Environmental and Engineering Research Institute, Lanzhou, China
Source Cold Regions Science and Technology, 66(1), p.30-38, . Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0165- 232X
Publication Date Apr. 2011
Notes In English. Based on Publisher- supplied data GeoRef Acc. No: 309482
Index Terms embankments; permafrost; railroads; slopes; soils; soil temperature; solar radiation; temperature; thawing; thaw depth; China--Qinghai-Tibet Railway; Asia; China; depth; Far East; monitoring; permafrost table; Qinghai-Tibet Railway; thermal effects
Abstract The difference in solar radiation produces a predictable thermal effect on the sunny and shaded slopes of embankments constructed in permafrost regions of the Qinghai-Tibet Highway and Railway, which results in differences in soil temperatures and the permafrost table under the shoulder. From the period 2005 to 2008, a systemic network of 42 sites was established along the Qinghai-Tibet Railway to monitor permafrost conditions and embankment performance. Soil temperatures up to 20 m in depth under the embankment were continuously measured hourly. In this article, we investigate daily mean soil temperatures under embankments for 25 observed sites and the temperature difference under the shoulder for both the sunny and shaded slopes of the embankments. We found significant differences in the thermal effect from the sunny and shaded slopes of the embankments along the Qinghai-Tibet Railway. On the sunny slope of the embankment the cooling process of soils under the shoulder is shorter and the thawing process is longer by 15-30 days than on the shaded slope. The multiyear average temperatures under the shoulder for the sunny slope are higher--0.23- 1.58C with an average of 0.86C--than those for the shaded slope. The temperature differences in winter DJF) are much larger than those in summer (JJA). The multiyear mean permafrost table under the shoulder for the sunny slope of the embankment is larger than for the shaded slope, ranging from 0.1 to 3m, with an average of 1.13 m. However, engineering measures can effectively reduce the thermal effect between the sunny and shaded slopes of embankments, resulting in a decreasing temperature difference that ranges from 0.46 to 0.71C, with an average of 0.58C.
URL http://hdl.handle.net/10.1016/j.coldregions.2011.01.001
Publication Type journal article
Record ID 65006625