Analysis of capillary barrier effect and design thickness with loess-gravel cover
JIAO Wei guo, ZHAN Liang tong, LAN Ji wu, CHEN Yun min
MOE Key of Laboratory of soft soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China.
School of Civil Engineering, Guizhou Institute of Technology, Guiyang 550003, China
The capillary barrier effect of clayey loess-gravel cover was verified and preliminary design thickness was analyzed in order to study the applicability of capillary barrier cover with loess and gravel in the northwest of China. Extreme rainfall test was conducted on the loess-gravel capillary barrier cover at Xi' an, Jiang Chun landfill. Water storage capacity of the cover was measured. The capillary barrier effect in clayey loess-gravel cover was illustrated and the thickness of loess capillary barrier cover was analyzed. Compared with the monolithic cover with 1 m thick loess layer, the total water and effective water storage capacity for the capillary barrier cover with the same thickness of loss layer were increased by 24.9%～31.8% and 38.2%～48.9%, respectively. The maximum water storage in the loess-gravel capillary barrier cover was measured as 116.92 mm in the extreme rainfall test. Compared with the field measurement, the theoretical value of water storage calculated by drying SWCC was 10.91% greater, and theoretical value of water storage calculated by wetting SWCC was 16.40% lower. When using the gravel, coarse sand and medium sand as a coarse soil and using the clayey loess as a fine soil to form a capillary barrier cover,the preliminary design thickness of the loess cover was between 1.06～1.12 meters calculated by drying SWCC, and it was 1.22～1.28 meters by wetting SWCC. In the preliminary design of cover, the thickness calculated by drying SWCC was conservative and it was non-conservative by wetting SWCC.
JIAO Wei guo, ZHAN Liang tong, LAN Ji wu, CHEN Yun min. Analysis of capillary barrier effect and design thickness with loess-gravel cover. JOURNAL OF ZHEJIANG UNIVERSITY (ENGINEERING SCIENCE), 2016, 50(11): 2128-2134.
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