岩土力学2012，Vol.33Issue(6)：1679-1688,10.
单轴压缩非贯通节理岩石尖端塑性区及弹塑性断裂模型研究
Crack tip plastic zone and elastoplastic fracture model for nonpenetrating jointed rock mass under uniaxial compression
摘要
Abstract
An elastoplastic fracture model for jointed rock mass under compressive loading is presented. In order to account for the mixed mode plastic zone model of wing crack tip of jointed rock under small scale yielding, the dimensionless function of the plastic zone diameter based on the Drucker-Prager (D-P) criterion is derived. The plastic zone models of mode I, mode II and mixed-mode (I+II) are compared with plastic zones obtained by Mises criterion and the influences of different Poisson's ratios for mixed-mode plastic zones of wing crack tip are studied. It is shown that the mode I and mixed-mode plastic zones of D-P criterion are larger than that of Mises criterion; and its mode II and mixed-mode plastic zones are not continuous between the upper and lower surfaces of wing crack. Moreover, plastic yield criterion is employed simultaneously with the fracture softening to describe the behaviors of jointed rock based on D-P criterion. The conception of fracture softening factor is introduced to characterize the softening feature of crack propagation. Regarding the strain energy density of wing cracks at joint-tip is responsible for the evolution of fracture softening of jointed rock. Thus, the behavior of fracture softening can be developed by proposed function of strain energy density. Borja's strain hardening/softening function is employed as the plastic yield function, regarding the plastic inner variables and stress as two impact factors of the hardening function. The elastoplastic fracture model with its numerical algorithm is proposed; and the code of elastoplastic fracture model is implemented by using return mapping implicit integration algorithm. The influences of friction coefficients, initial joints orientation and stress intensity factor on the constitutive response under uniaxial compression are studied. The results are generally in good agreement with experimental data of uniaxial compression tests of jointed marble.关键词
节理岩石/应变能密度/塑性软化/断裂软化因子/隐式积分算法/D-P准则/尖端塑性区Key words
jointed rock mass/ strain energy density/ plastic softening/ fracture softening factor/ implicit integration algorithm/ D-P criterion/ crack tip plastic zone分类
建筑与水利引用本文复制引用
袁小平,刘红岩,王志乔..单轴压缩非贯通节理岩石尖端塑性区及弹塑性断裂模型研究[J].岩土力学,2012,33(6):1679-1688,10.基金项目
国家自然科学基金资助(No.41002113,No.41162009) （No.41002113,No.41162009）
中央高校基本科研业务费专项资金资助(No.2011PY0190,No.2010ZY45) （No.2011PY0190,No.2010ZY45）
教育部科学技术研究重点项目(No.2011175). （No.2011175）
