Influence of reconsolidation stress history and strain rate on the behaviour of kaolin over a wide range of strain

In conventional laboratory testing, the reconsolidation procedures and shearing strain rate are known to influence the characteristics of clays and in particular their subsequent stress – strain behaviour. In this study the influence of reconsolidating Stress Ratio along five different stress paths (K_c=1.0,0.8,0.7,0.64 or 0.6), OCR and strain rate was evaluated over a wide range of strain from ε_a < 0.001% to post peak values of ε_a > 25% and the importance of so doing is reported. This study also shows that most existing theories characterizing the deformation and strength behaviour of clays which assume that failure for a normally consolidated clay occurs at the Critical State Line (CSL) irrespective of drain condition, strain rate and stress path traversed towards the CSL, are inadequate and may need modification.