Abstract:

Most parts of the Tianjin Binhai New Areas consist of lands formed by reclamation. The foundation soil is hydraulically filled materials and strengthened by vacuum preloading technique. Therefore, the soil in this region has some unique properties, such as the creep characteristics, which has great influences on the long term displacement and stability of the soil foundations of upper structures. The creep properties of undisturbed soil samples taken from construction sites in this area are tested under unconsolidated and undrained triaxial conditions. Based on the test data, a no-yield-surface constitutive model is established, which can simulate the creep properties of foundation soils in the Tianjin Binhai New Areas. The model contains five parameters that have definite physical meanings and can be determined with the test data. The predicted results with the established model agree well with the observed data through the tests. The numerical model can be used to estimate the long term displacements and stability of the soil foundations of existing structures.

Key words: soft clay, creep, triaxial creep test, no-yield-surface, constitutive equation