The parameters of Duncan Et-?t

Et-Bt and constant ?t models for the normal consolidated Wuhan clay are obtained by a series of drained conventional triaxial compression tests; the rationality and validity of parameters are confirmed by the finite element analysis; and it provides a reference for the application of Duncan models in Wuhan area. In view of a hyperbolic approximation has been suggested to describe the axial strain-radial strain relationship in Duncan Et-?t model

but the points of test results of real soils are frequently found to deviate from the ideal relationship

indicating that the axial strain-radial strain curves of real soils are not precisely hyperbolic in shape; and it results in some difficulties in parameter fitting. For best agreement of the theoretical and test results

a modified method is proposed that the straight line of ?3 /?1-?3 relationship be fitted to test data at the two points corresponding to stress difference equal to 70 % and 95 % of the peak strength. The validity and superiority of the modified method are attested by the contrastive analysis of prediction of the volumetric deformation of soil samples which adopt Et-Bt model

constant ?t model and the modified method. In addition

the method is simple in form and convenient to use.