Theory and application of measuring the albedo of crushed-rock layer embankment in permafrost regions
TAN Kanghao1，2，QIN Yinghong1，2，LIANG Jia1，2，PANG Ruyue1，LI Yunfeng1
(1. College of Civil Engineering and Architecture，Guangxi University，Nanning，Guangxi 530004，China；2. Key Laboratory of Disaster Prevention and Engineering Safety of Ministry of Education，Guangxi University，Nanning，Guangxi 530004，China)
Abstract：A novel method for measuring the albedo of crushed-rock layer was proposed in this paper. The albedo of the crushed limestone layers with single-size aggregates of 1，2，3 and 5 cm sizes was measured respectively to reveal the main factors controlling the albedo of the crushed-rock layer. The layer was painted with the high-reflective pigment to increase the albedo of the crushed-rock layer and then the albedo of the painted layer was measured. The albedo of the crushed-rock layer was tested and compared against the albedo measured by the ASTM E1918A. It was found that when the variation of the incident solar intensity was less than 20W/m2 (tolerant errors stated by ASTM E1918A)，the ASTM E1918A either underestimate or overestimate the albedo of the crushed-rock layer up to 0.00–0.03. The reflectivity of the crushed-rock layer decreases with the aggregate size，and the albedo of the crushed-rock layer is 0.10–0.25 lower than that of the fresh flat crushed-rock. This difference is because photons leaving the crushed-rock layer have a probability to return to the layer，reducing the albedo of the crushed-rock layer. Painting the crushed-rock layer with high reflective pigment raised the albedo of the layer from 0.262 to 0.433. Raising the reflectivity of the crushed-rock layer on slope of embankment reduces the temperature of side slope and protects the permafrost stratum.
谭康豪1，2，覃英宏1，2，梁 槚1，2，庞如月1，李芸峰1. 冻土路基块(碎)石层反射率测量及应用[J]. 岩石力学与工程学报, 2017, 36(1): 254-260.
TAN Kanghao1，2，QIN Yinghong1，2，LIANG Jia1，2，PANG Ruyue1，LI Yunfeng1. Theory and application of measuring the albedo of crushed-rock layer embankment in permafrost regions. , 2017, 36(1): 254-260.
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2017, Vol. 36 
