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Instability of Volcanic Soils with Layers of Pumice Gravel


In areas of volcanic soils with layers of pumice gravel as in Southern Tanzania (East Africa), slope failures have been often observed during periods of heavy precipitations. In order to explain these failures, laboratory tests on pumice gravels and stability calculations have been carried out. The results show that in the dry and moist condition, the slope stability of pumice gravel is given by its high friction angle and is therefore quite good. If the pumice gravel is partly submerged, the very low density of the pumice governs however its stability. Failures may then take place under quite unusual conditions.


Bucher, Felix

Index Terms:

Soil; SoilGroup; Pumice; stability

Further Information:

Date published: 1998