Abstract: The typical soil of deep foundation pit in the Yellow River alluvial plain is clay and silty clay. These two kinds of soils have rheological characteristics. The supporting structure deformation and internal force is time-effected when excavating in this soil. In order to master the trend of each control index, a soil visco-elastoplastic model should be developed. Based on the data of soil laboratory test in Jinan Provincial Capital Culture and Art Center deep foundation pit, the visco-elastoplastic second order nonlinear Newtonian fluid model is given. And the relationship between visco-elastoplastic model parameters and test data is built. First, the constitutive model of incremental form is built. Second, the visco-elastoplastic model is secondary developed in FLAC. Lastly, we use this model to analyze the lateral displacement moment and anchor internal force of foundation pit supporting structure. Based on this test, the model precision is proved. A case study shows that, the lateral displacement change is increased gradually with the increase of time; but the early increase is larger and the later deformation tends to be stable. The change of supporting structure moment and anchor internal force is increased at first then decreased in a small amplitude in contrary to the lateral displacement.

Key words: deep foundation pit, visco-elastoplastic model, secondary development of FLAC, numerical simulation