Drained Residual Strength of Texcoco Clays Under Different Testing Conditions

This research presents the results of a study into the drained residual strength of high plastic remoulded clays from Valley of Mexico, specifically (a) former Lake Texcoco, located northeast of Mexico City, and (b) Academy of San Carlos, situated in the city center. Using a standard ring shear device following several testing procedures (single stage, multistage, pre-shear and flush). Specimens were subjected to torsional shear stresses with a displacement rate of 0.10 mm/min. The procedure that was adopted in this study was a single stage test. Tests performed using displacement rates of 0.01, 0.10, and 1.00 mm/min with different interfaces (porous stone, mortar, and steel) showed that the increase in displacement rate caused an increase in the residual friction angle, regardless of the type of interface. Other tests performed consolidating the samples under the same normal stress and sheared under the same displacement rate showed that increasing the consolidation time led to an increase in peak strength while the residual strength remained practically unchanged. This same behaviour was observed in another series of tests performed with OCR values of 1, 2, and 3.