Laboratory Reconsolidation and In Situ Stress State of Residual Soils in the Northern Andes

This study presents a laboratory testing program consisting of incremental loading, constant rate of strain, and specially designed, pseudo K0-triaxial tests to provide insight into the in situ stress state of residual soil masses and the ability to reproduce those in a laboratory environment. The testing program was conducted at two different sites derived from an igneous-metamorphic basement located in the northern Andes and included in situ measurements of earth pressure coefficients, K0, and shear wave velocities, Vs, to validate those measured in the laboratory. The laboratory tests and procedures along with the direct comparison with field measurements are also used to evaluate disturbance effects on compressibility responses. The results indicate that K0 recompression to the overburden stress is adequate for reproducing the in situ stress state of the tested residual soils. Similar to sedimentary soils, laboratory testing of large residual soil specimens results in less disturbance.