Laboratory measurement of strength mobilisation in kaolin: link to stress history

This letter presents data from triaxial tests conducted as part of a research programme into the stress–strain behaviour of clays and silts at Cambridge University. To support findings from earlier research using databases of soil tests, eighteen CIU triaxial tests on speswhite kaolin were performed to confirm an assumed link between mobilisation strain (γ_M = 2) and overconsolidation ratio (OCR). In the moderate shear stress range (0·2c_u to 0·8c_u) the test data are essentially linear on log–log plots. Both the slopes and intercepts of these lines are simple functions of OCR.