The frost penetration with the modified soil in the landfill bottom liner system

Abstract

Many researchers have studied on the effect of freeze/thaw phenomena mainly on compacted soil samples of small diameter: Most of the experiments done so far were applied to study those effects on pavement design in civil engineering. The paper relates the freeze/thaw studies performed on large scale equipment to better simulate these effects under the existing field conditions in a landfill. A large scale (1.0 m×1.5m×2.0m) laboratory simulates the field depth of the bottom liner systems with the cold climate and it was also introduced many boundary conditions similar to those encountered in the landfill. As a bottom liner materials, the modified soil (mixed stabilizers, clays, cements, and clay minerals) was used instead of the natural clay. From bottom to top of this lysimeter, one can identify two layers: a) bottom liner of 30 cm; b) a stabilizer soil layer of 75cm. As results of the performed frezee/thaw simulations, it was found out that the depth of frost penetration increased a few centimeters more with 35–40 mm/hr simulated than that performed without simulated rainfall. Then, the frost heave increased a few millimeters. Also, a few cracks appeared, but they were not severe neither significantly opened. The results showed that compacted modified soil is as much as reliable the regual compacted clay liners normally used in landfill construction, submittd to strong winter conditions.