Numerical simulation of moisture balance in evapotranspiration landfill cover.

The compacted clay cover systems of landfills were studied for desiccation cracks (dry crack or thowing crack for climate). The niechanism of a new type of evapotranspiration cover was analyzed to promote the engineering performance. On the basis of considering precipitation and evaporation, a one-dimensional dynamic model was developed for simulating moisture transport in evapotranspiration landfill cover. Volumetric water content was simulated based on the data of precipitation and evaporation of Dalian in 1976. Result of simulation is analyzed. It is apparent that the moisture content near the surface is highly sensitive to climate loading, but the effect is significantly attenuated and time-lagged along with increasing depth. Moisture content of barrier soil layer is partially saturated. Evapotranspiration landfill cover (thickness:150 cm)is absolutely able to resist strong precipitation which is the heaviest one in 48 a of Dalian. Parametric analyses are conducted to simulate variations in precipitation rate, precipitation event duration and barrier soil layer thickness. The experimental data are used to provide a quantitative verification of the model. The model simulations are compared with the data, which reasonably agree with model simulation. The simulation model provides scientific evidence for building evapotranspiration landfill cover. [ABSTRACT FROM AUTHOR]