Residual soils are developed at inter-tropical latitudes where climate conditions favor the in-situ weathering of the intact rock. They are characterized by a porous structure with high void ratios that makes them susceptible to large deformations. Soil compressibility in residual deposits is usually evaluated based on conventional Incremental Loading (IL) consolidation tests which can take up to a week to be completed and yield very limited stress-strain data. This paper employs the results of Constant Rate of Strain (CRS) consolidation tests to evaluate the compressibility behavior of two residual soils derived from igneous-metamorphic basement located around the city of Medellin, Colombia. CRS testing significantly reduces testing time and provides continuous pore water pressure and load- deformation data leading to a better definition of the yielding stress of the material. Testing was performed on hand-trimmed specimens cut from high-quality block samples. For each site, one IL and three CRS tests at different strain rates were completed. It was found that CRS testing accelerates the definition of compressibility parameters with respect to conventional IL tests and yields very similar results to conventional oedometer tests. CRS testing can be used to study strain rate dependency in the definition of the yield stress of the tested residual soils. These values increased 22% for strain rates of 20%/hr with respect to average values estimated from IL testing.
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