坝体与坝基材料参数的薄层单元有限元反分析

为了更加合理有效地反演大坝坝体及坝基岩体材料的物理力学参数,对基于薄层单元有限元的反分析方法进行研究。在常规三维有限元基础上,通过设置薄层单元来模拟坝体裂缝和坝基岩体断层、软弱夹层及破碎带等构造,它能有效模拟界面的张开和剪切滑动等特性;探讨了薄层单元分析的原理和方法,并针对坝体混凝土弹模和坝基变形模量等参数,提出具体的反演分析方法。工程实例计算结果表明,与常规三维有限元反分析方法相比,薄层单元有限元模型能更好地反映大坝结构及其基础构造的实际状况,因而其参数反分析结果更为合理可靠。

LAMELLAR ELEMENT FEM INVERSE ANALYSIS OF MATERIAL PARAMETERS OF DAM AND BED ROCK

In order to carry out an effective and rational inverse analysis of physico-mechanical parameters of dam concrete and its bedrock materials,an inverse analyzing method based on lamellar element FEM is proposed.By setting up lamellar elements in general 3D FEM to simulate the dam concrete cracks and the bedrock conformations such as fault,weak interlayer and cracked belt,the inverse analysis method proposed can effectively simulate the interfacial characteristics of opening,cutting and sliding.Both the principle and method of lamellar element FEM are presented,and then a practical method and its operation steps of parameter inverse analysis based on lamellar element FEM is proposed to obtain the dam concrete elastic modulus and bedrock deformation modulus.The calculation of an engineering example shows that the inverse analysis method based on lamellar element FEM can reflect the real conditions of dam structure and the bedrock conformations more objectively than that based on the conventional 3D FEM,and so the parameters calculated by the proposed inverse analysis method are more reasonable and reliable than the latter.