Abstract:

There are 4 seepage models in the FLAC3D finite element software; it is decided by selecting proper seepage models whether the result of numerical calculation is right or not. The seepage field distribution in threedimensional space is complicate; as a result, it is difficult to decide a quantitative yardstick. There are different selection methods in different references. It is necessary to make stress analysis on the 4 seepage models, so as to choose a simple, rapid and rational model selection method. Four construction cases based on the 4 seepage models are designed, with a 100 m×100 m×10 m isotropic elastic cube as an example. The total stresses and seepage field distributions of the 4 construction cases are compared. The conclusions drawn are as follows: 1) For model A and model C, the soil skeleton carries all loads; for other 2 models， the fluid carries partial load too. 2) The load sharing ratio of fluid is based on the stiffness ratio and time. The solidfluid coupling process in FLAC3D is realized by adjusting the stiffness ratio and switching mechanicsfluid process. So far, the calculation of solidfluid coupling is almost based on FLAC3D in China. The conclusions can be applied to foundation engineering and underground engineering, and the paper can provide reference for similar projects.

Key words: solidfluid coupling, seepage model, FLAC3D, geotechnical engineering