| Based on the modified Cam-clay model,the United Hardening model is an elasto-plastic model proposed by applying the transformed stress tensorσ<sup><sub>ij that is based on the SMP and the new hardening parameter H<sup>.The model can reasonably describe the stress-strain behavior of clay and sand in three-dimensional and only five conventional soil parameters are needed in the model.So if the subroutine about the United Hardening model is add to ANSYS by used of the secondary development UPFS,not only the advanced preprocessing and post-processing of ANSYS will be used,but also the rationality of forecast about the problem of the geotechnical engineering by used of ANSYS is improved.In this paper,at first according to the failure behavior of the friction material in theл-plane and some classical test result about the sand,the character of shape parameter of generalized nonlinear strength criterion is studied,and the experiential formula about the shape parameter and the failure stress ratio in the criterion wad found,So that it is easy to combine the criterion to the United Hardening model.At the second,elacto-plastic stiffness matrix based on the United Hardening model is introduced by the basic principle of elacto-plastic finite element.We research the calculating approach of elacto-plastic finite element according with the United Hardening modelIn last,the United Hardening model combines with ANSYS to build appropriate soil material model by use of Secondary Development of ANSYS.We calculate the experimentation sample based on the above model,make use of ANSYS post-process to analyze the result,research the deformation and stress of point under equal load and distribution of additional stress and analyze stress path of soil.The calculation is reasonable through comparing result with the calculation result of the Cam-Clay,original DP model of ANSYS and observing data. |
