Abstract: The design shear strength values of different soil layers for the design and construction of a metro station in Suzhou City obtained from various laboratory tests were statistically analyzed. It is concluded that the shear strength values from different test methods, such as, unconsolidated undrained direct shear, consolidated undrained direct shear, unconsolidated undrained triaxial shear, consolidated undrained triaxial shear, are different. Further, significant variation in shear strength values could be obtained from different test methods. The cohesion values obtained from the undrained unconsolidated direct shear are higher than those of from consolidated undrained direct shear tests. The internal friction angle, other the other hand follows the reverse relationship. The internal friction angles from silty clayey sample in triaxial unconsolidated undrained shear test re very small and close to zero, which is the theoretical value. The cohesion values obtained from triaxial unconsolidated undrained shear test are higher than 〖JP2〗those of from unconsolidated undrained direct shear tests. Under total stress conditions, the internal friction angle and cohesion values obtained from consolidated undrained triaxial shear tests are higher than those of from direct shear tests.

Key words: Shear Strength Design Values, Unconsolidated Undrained Direct Shear Tests, Consolidated Undrained Direct Shear Tests, Consolidated Undrained Triaxial Shear Tests, Unconsolidated Undrained Triaxial Shear Tests