Abstract:

The functions of intermediate covering layer of landfill include temporary enclosure of garbage, control of rainfall infiltration, reducing mosquito breeding, etc. High density polyethylene (HDPE) film is easy to pierce to cause rain infiltration, but the cost is high. The northwest area of China is dry, with loess widely distributed. It is convenient to be used as a landfill intermediate cover. Experimental studies are carried out on tamping construction, impervious performance and impervious performance deterioration after wetting and drying cycles. The results show that the saturated permeability coefficient of loess increases with increasing dry density. Dry density reaches 1.60 g/cm³ when its permeability is from 10⁻⁷ cm/s to 10⁻⁶ cm/s. The field double ring in situ experimental permeability coefficient is 8.37×10⁻⁸ cm/s, about double as in the indoor test. With the natural drying wetting cycle condition of saturated infiltration coefficient being 1.18×10⁻⁶ cm/s, it is 14 times greater than the condition without crack. Adding a soil vegetation layer with thickness of 15 cm, cracking of loess is suppressed.

Key words:  anti-seepage performance,  loess ,  temporary cover , landfill