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通过对比北麓河试验段U型块石路基结构和普通路基下部土体温度监测研究,U型块石路基显著地抬升路基下部多年冻土上限,具有较强的降低多年冻土温度的作用.2005—2007年间,U型块石路基下多年冻土上限平均抬升幅度达0.9~1.4 m.路基中心下部0.5 m深土体温度降温幅度达1.13℃,原天然上限附近土体温度降温达1.28℃,5 m深的多年冻土降温幅度达0.77℃,且U型块石路基下部土体温度呈现逐年降低的趋势.然而,普通路基下部土体温度远比U型块石路基下部要高,2005年普通路基下部0.5 m深土体年平均温度比U型块石路基高1~3℃,1.5 m处高0.8~1.9℃,5 m处高1.2~1.5℃.同时,U型块石路基下部多年冻土上限抬升比普通路基大,2004—2006年间U型块石路基左路肩下多年冻土上限抬升比普通路基大0.86 m,路基中心大0.5 m.
By comparing the study of U-shaped block embankment structure and the soil temperature monitoring in the lower part of ordinary embankment in Beiluhe Experimental Section, the U-shaped block embankment obviously raises the upper limit of the permafrost in the lower part of subgrade, which has a strong effect of reducing the temperature of permafrost. Between 2005 and 2007, the average upper limit of permafrost under U-shaped block embankment reached an average of 0.9-1.4 m, and the temperature drop of soil layer at the depth of 0.5 m below the subgrade center was 1.13 ℃. The temperature of soil near the natural upper limit reached 1.28 ℃ , And the temperature drop of permafrost at 5 m deep reaches 0.77 ℃, and the temperature of soils in the lower part of U-shaped block tends to decrease year by year.However, the soil temperature in the lower subgrade of ordinary embankment is much higher than that of the lower part of U- The average annual temperature of 0.5m deep soil layer in the lower part of normal subgrade is 1 ~ 3 ℃ higher than that of U-shaped block, 0.8 ~ 1.9 ℃ at 1.5m and 1.2 ~ 1.5 ℃ at 5m. Meanwhile, The increase of permafrost upper limit is larger than that of ordinary subgrade, and the permafrost upper limit lifting of the permafrost on the left shoulder of U-shaped block subgrade is 0.86 m larger than that of ordinary subgrade in 2004-2006 and 0.5 m larger than the subgrade center.