Volume 32, Issue 3 (May 2009)
Proposed Protocol for Characterizing a Clay Layer Subjected to Bending
Solid waste landfills have a cover barrier including a compacted clay liner which is the major element of the safety of the site. However, this barrier encounters many problems, in particular those related to its implementation and to the mechanical loading, such as potential differential settlements within the waste, after closing the cell. This phenomenon can induce bending strains in the clay layer and so create damage. The originality of this work is that the study includes the comparison of results from different types of standard tests, inducing compressive and tensile stresses. Compression tests, under low confinement, have been performed in the laboratory to characterize the clay behavior and to compare results with four-point bending tests. Particular attention is paid to experimental results by focusing the analysis on failure initiation. For the bending test, the limit value of the extension strain of the clay layer without damage is characterized. To optimize the landfill cap cover, particularly in terms of deformability, an improvement of the mechanical clay layer capability is proposed by addition of fiber reinforcement.