A series of undrained triaxial compression and extension tests with pore water pressure measurements were performed on undisturbed samples of fibrous peats, which were normally and overconsolidated under isotropic stress condition. Test results indicate that void ratio vs, effective pressure relationships during isotropic compression and swelling can be approximated by the straight lines on Q In a-d in p plane, and that stress-strain behaviour and strength parameters, cu/Po, o, c are strongly

more »

... fected by fabric anisotropy and stress history. Based on the test results, the authors proposed a method for predicting stress-strain behaviour of normally consolidated peat under triaxial compression and extension conditions. Moreover, the method, by which the values of undrained strength parameters of overconsolidated peat by using the test data on normally consolidated peat can be estimated, was shown and the validity of the method was verified by the test results.