THE VARIATION OF SHEAR MODULUS OF A CLAY WITH PRESSURE AND OVERCONSOLIDATION RATIO

A method is described for expressing the elastic shear modulus of a clay as a power function of the applied pressure and the preconsolidation pressure. The method has the advantage that it incorporates the concept of normalisation of clay properties with respect to pressure, whilst allowing a realistic variation of the shear modulus with overconsolidation ratio to be described. A further advantage is that, since the shear strength is often expressed in a similar manner, the rigidity index G/su, which plays an important role in many geotechnical engineering analyses, can be expressed as a power function of the overconsolidation ratio. The new method is compared with some existing data showing the variation of the stiffness of clays.