加锚固体的三维复合单元模型研究

首先提出了复合单元的概念，然后将其应用于建立砂浆固结锚杆的分析模型。该模型考虑了岩体、砂浆、锚杆、岩体/砂浆接触面，砂浆/锚杆接触面等多重介绍，借助阶谱的概念，复合单元可以纳入常规有限单元法分析中去，当某单元不含锚杆时，即退化为常规有限单元。应用该模型进行加固布设优化分析，当单元内锚杆的数量与方向改变时，计算网格无需变化，从而为大规模三维复杂结构计算分析的前处理提供较大便利，模型在有限单元软件CORE3中实现，并提供了计算实例。

STUDY ON THE THREE-DIMENSIONAL COMPOSITE ELEMENT MODEL OF BOLTED ROCK MASSES

The general composite element concept is proposed firstly, then the principle of the model is used to establish a fully-grouted rock bolt element model which comprises rock material, grout material, bolt material, rock-grout interface and bolt-grout interface. The composite element can be incorporated into the conventional finite element analysis easily with hierarchical technique. On one hand, when one element contains no bolt segments, the composite element will be degenerated into the conventional finite element. On the other hand, if the number and direction of bolts are changed in the optimal reinforcement design, the FE grid will keep unchanged. In this way the mesh generation of the large scale reinforced rock structures becomes relatively convenient and feasible. The model has been implemented in the FEM software CORE3, and some numerical examples are presented.