INFLUENCE OF STRAIN RATE ON THE RESIDUAL STRENGTH OF A KAOLINITIC CLAY

DIFFERENCES IN THE RESIDUAL STRENGTH OF CLAY MAY ARISE FROM THE VARIOUS METHODS USED TO TEST IT BECAUSE OF THE LIMITATIONS OF EACH. THE CURRENT LITERATURE REVEALS THAT THE RESIDUAL STRENGTH OF NATURAL CLAYS OR CLAY MINERALS MAY DEPEND ON A NUMBER OF FACTORS AMONG THEM STRAIN RATE. IN THE INVESTIGATION DESCRIBED IN THIS TECHNICAL NOTE, THE STRAIN RATE INFLUENCE WAS STUDIED BY ADOPTING A MODIFIED PROCEDURE OF HUTCHINSON. DETAILS ARE GIVEN OF THE ATTERBERG LIMITS. GRAIN SIZE DISTRIBUTION, SPECIFIC GRAVITY, ACTIVITY AND ORGANIC CONTENT OF THE KAOLINITIC CLAY SAMPLES FROM BANGALORE INDIA, WERE USED IN THE INVESTIGATION. THE CONSOLIDATED SAMPLES WERE MOUNTED IN A DIRECT SHEAR BOX ALLOWED TO SATURATE UNDER NORMAL LOAD, AND TESTED UNDER NORMALLY CONSOLIDATED CONDITIONS. DURING THE FIRST FORWARD START, A LOW RATE OF STRAIN WAS APPLIED; THIS ALLOWED FOR COMPLETE PORE PRESSURE DISSIPATION AND BROUGHT THE PARTICLES AT THE EFFECTIVE STRESS STAGE. THE STRUCTURE AT THE RESIDUAL STAGE WAS STUDIED BY THE SHRINKAGE RATIO TECHNIQUE, THE SHRINKAGE RATIO WAS ALSO DETERMINED AT PEAK STAGE. /TRRL/