岩体材料包络型复合弹塑性计算模型

Combinatorial elasto plastic model of enveloping type for rock mass materials

提出了考虑岩体低抗拉性质的三参数屈服准则。将该屈服准则与Ｍｏｈｒ－Ｃｏｕｌｏｍｂ（简称ＭＣ）或Ｄｒｕｃｋｅｒ－Ｐｒａｇｅｒ（简称ＤＰ）屈服准则联合使用时，形成具有包络型的、基于ＭＣ（ＤＰ）的三参数复合弹塑性模型，克服了常规的ＭＣ（ＤＰ）或带截断的ＭＣ（或ＤＰ）屈服准则不能或只能简单考虑岩体低抗拉性质的缺点。同时，提出了岩体材料屈服后的包络型软化曲线，为岩体材料的非线性计算提出了完整的计算模型。此外，还给出了基于ＭＣ（ＤＰ）的三参数包络型模型应力积分“向后欧拉”算法及一致性弹塑性矩阵有关公式，使建立在此基础上的Ｎｅｗｔｏｎ－Ｐａｐｈｓｏｎ解法具有二阶收敛性。

Three parameter yield criterion to simulate the lower tensile property of rock mass is presented in this paper. It brings out three parameter elasto plastic computational model with MC(or DP) yield criterion. The disadvantage of the conventional MC(or DP) criterion with tensile cut off unable to deal with the lower tensile property of rock mass is overcome by this model. The envelopes of softening curves for post yielding of rock mass materials are also presented to give the complete computational model. The 'Back Euler' stress integration algorithm and the consistent elasto plastic matrix for this model are also given for assuring the Newton Raphson interation convergence to be of the second order.