Swelling and collapse of compacted soils to be used as earth dam cores

Abstract

Abstract. The mechanical behaviour of fine-grained soil materials to be used as impermeable cores for earth dams has been extensively studied by numerous researchers. The required properties of these materials have also been very well described by standards and specifications. Yet, more than often it is required to assess their swelling/collapse potential, especially at various vertical stresses, as a means to estimate their volume changes upon inundation which is going to be caused by filling the dam reservoir. In the paper, experimental results of five different soils are presented. The soils tested ranged from non-plastic silty sands with clay to medium plasticity clayey silts that were compacted in conditions dry, at and wet of optimum moisture content as derived from standard compaction energy Proctor tests, then subjected to one-dimensional loading conditions and then inundated. The vertical stress was up to 7.6 MPa. The experimental results are categorized according to initial moisture content relative to Proctor optimum and indicate expected magnitudes of strains due to inundation for various grain-size distributions and plasticities.

The combination of splitting tensile strength and unconfined compression tests on unsaturated soils to measure the evolution of unsaturated shear strength

“…High, steep slopes are formed in the formation by sea erosion of their toe with occasional landslides occurring along the 5km coast that the formation outcrops in the highest slopes. The SWCC of the undisturbed material and its recomposed counterpart have already been reported [5]. Parnitha weathered siltstone is found in mount Parnitha 30km to the north of Athens close to the ground surface.…”

“…The Corinth Marls are a very well-studied formation [4] through which the Corinth Canal was excavated in late 19th century and extensive remediation measures for instabilities that closed the canal are currently constructed. Various experimental investigation programmes have been undertaken in order to investigate the properties of this material including the SWCC of the undisturbed marl and its recomposed counterpart [5], where recomposed is the material consolidated from a slurry condition to a desired value of void ratio (preferably that of the undisturbed soil) and then unloaded to zero stress. The Chalkoutsi Marl is a formation found 35km north of Athens.…”