The Research And Application On The Efficient Finite Element Method Based On Nonlinear Constitutive Model In Underground Engineering

Underground engineering finite element calculation of the material is mainly involved inthe soil or rock material, the nature of the soil is extremely complex, because of the geologicalbody has no continuity, heterogeneity, anisotropy and the existence of complex groundwaterand the initial stress conditions, a lot of geotechnical problems are difficult to come up withanalytical solution. According to these complex geotechnical engineering, if only think ofgeotechnical linear elastic, it is difficult to get accurate, real results. Based on theEfficient and local accuracy reduction algorithms,this paper will lead into the soil nonlinearconstitutive model, making the original algorithm can not only solve linear elastic problemand can solve nonlinear problem, and making the calculation results more closer to the realsituations.In the actual of underground engineering, finite element method applied in undergroundengineering, if the distribution of the division of meticulous grid according to the material ingeotechnical engineering will make the grid dividing work very difficult and complex. Thispaper introduced into the algorithm composite units, when calculation of each gauss point iscalculated, and give each gauss point properties directly, the same unit of the gauss points canhave different attribute by this method we can adopt uniform rules are hexahedron units ofgrid partition, make the grid partition quick and easy, greatly reducing the processing of thework and enhance the overall calculation efficiency, especially suitable for undergroundengineering, can quickly get the most attention we whole structural characteristics (such aswhole displacement settlement). This article mainly are:(1) Introduces the basic principles of the current nonlinear finite element analysis forunderground engineering.(2) Comparing the calculation results of the new algorithm in order to facilitate thegeneral purpose finite element program ANSYS, the introduction of the Drucker-Pragerelastoplastic constitutive model,and introduces Drucker-Prager elastic-plastic constitutivemodel, and then gives Drucker-Prager model based on the efficient and reduce localprecision the principle and implementation of algorithm process, thus fulfilling the high efficiency and precision of the algorithm in the lower local nonlinear areas ofapplication.(3) Use c++language of efficiency and accuracy of the algorithm reduce local nonlinearfinite element program, and by using the incremental iteration method to set up in the paperfor solving nonlinear equations. In addition, this paper briefly introduces the operationprocess of the program.(4) Two underground engineering example are designed, realizing the ideal soilelastoplastic numerical simulation. The examples show that the calculated results of thegeneral purpose finite element software ANSYS and the procedures in this articleconsistent with the calculationresults are satisfactory, but also reduce the preparationtime, to verify the feasibility and efficiency of the proposed method.