关键词: 岩土工程, 有限元, 过渡等参单元, 插值函数, 积分格式

Abstract: In the 3-D finite element analysis of complex geotechnical structures such as earth-rockfill dams, the hexahedral elements with a high precision are generally adopted with being supplemented by some degradation elements as transition. Because of their poor geometric properties, the degradation elements could degrade the precision of the finite element method. One way to overcome such a problem is to adopt transitional isoparametric elements. Here the interpolation functions, integral coordinates and weighting coefficients are summarized for some common transitional elements such as 3D wedge, tetrahedron and pyramid elements and implemented into a finite element program. By comparing the finite element analysis results of an ideal earth dam using hexahedron elements and pyramid elements, respectively, it is shown that the pyramid elements are sufficient with regard to the precision. The three kinds of transitional elements are then used in analyzing a real earth-rockfill dam, and the numerical results show that use of transitional isoparametric elements can improve the computional accuracy to some extent. Finally, the quadratic isoparametric elements are analyzed and adopted in a dynamic analysis of the elastoplasticity problem. Use of the quadratic isoparametric elements can substantially improve the precision in calculating the excess pore pressure.

Key words: geotechnical engineering, finite elements, transitional isoparametric element, interpolation function, integral scheme