SIMULATION OF SPOIL PILE SUBSIDENCE

Post-reclamation subsidence of cast-back smectitic overburden (spoil) results in an impaired land use value due to continued slow straining, differential subsidence, and occasional development of sinkholes and tension cracks. An attempt to simulate subsidence in a controlled laboratory study was undertaken. The study has identified several phenomena such as lump softening (loss of suction) on resaturation, and the lack of any effect of water salinity. Also, there is a need for rational field guidelines for compaction to minimize post-reclamation subsidence. (Author/TRRL)