摘要
传统离散单元计算方法(包括UDEC和DDA法)适合于求解岩土工程中有较多地质界面的问题,分析层状围岩体或大块体时仍需要离散化为若干小块体,为此增加许多不必要的人工界面,而有限元法等连续性方法并不适合表达有较多非连续面的问题。为此以DDA法为基础,建立无网格法高阶插值的DDA块体模型,原理上即利用无网格插值或近似方法如移动最小二乘法等,以获得离散大块体的复杂位移变形场,遵循原DDA法建立块体系统刚度矩阵、进行动力迭代分析的基本原理,实现无网格法与DDA法内部耦合分析。新方法模型针对层状围岩体,在建模分析上方便直接,数值算例表明对隧道层状围岩体分析结果是合理有效的。
Traditional discrete element methods(including UDEC and DDA etc.) are adaptive to analyze geotechnical engineering projects with numerous discontinuous geological interfaces,with these methods it is needed to mesh large or stratified geological bodies into small discrete blocks.In this way many artificial interfaces,which may bring about troubles,are unnecessarily produced out.It is known that the numeric methods of continuum mechanics such as Finite Element Method are inefficient to treat discontinuities.A new numeric method is proposed here,it is based on theory of Discontinuous Deformation Analysis(DDA) method,and the high - order meshless displacement approximation functions are innovatively introduced to describe the block displacement and deformation,e. g.the Move Least Square(MLS) functions,so this method is essentially a coupled one of DDA with meshless displacement functions,it uses the similar methodology of DDA such as implicit solution with assembled stiffness matrices of the block system,dynamic computation,etc.On its application to stratified rockmass surrounding the tunnels, this method is advantageous to simulate the structures of these rockmass straightforwardly and precisely,numerical examples are provided to demonstrate its feasibility.
出处
《地下空间与工程学报》
CSCD
北大核心
2009年第A6期1086-1091,共6页
Chinese Journal of Underground Space and Engineering
基金
国家自然科学基金资助项目(40672184)
关键词
无网格法
DDA
移动最小二乘法
层状围岩
隧道
meshless methods
Discontinuous Deformation Analysis(DDA)
Move Least Square method(MLS)
stratified surrounding rockmass
tunnel
