摘要
岩石材料本构模型是进行岩体工程设计与分析的基础。为了建立能够准确反映脆性岩石变形破坏全过程模拟方法,针对当前统计损伤本构模型难以很好地反映脆性岩石峰前变形力学性质的局限性,进行了深入分析。首先,在脆性岩石变形力学特征分析基础上考虑初始空隙闭合及其影响,并由此将其分为两类:第1类初始空隙和第2类初始空隙,其中,第1类初始空隙仅能够在静水压力状态下发生闭合,其闭合程度对脆性岩石弹性模量变化特征产生影响,且其未闭合部分引起脆性岩石具有初始损伤;第2类初始空隙能够在任意应力状态下发生闭合,且能够在脆性岩石初始宏观变形阶段完全发生闭合,其闭合程度对脆性岩石初始压密变形阶段与初始宏观非线性变形曲率均产生影响。其次,脆性岩石被抽象为由裂隙材料和骨架材料两部分组成并基于材料变形力学分析方法建立脆性岩石变形分析方法,然后基于瞬时应变和统计损伤理论分别建立裂隙材料变形分析方法和骨架材料变形分析方法,进而建立考虑初始空隙闭合及其影响的脆性岩石本构模型,并给出了模型参数的确定方法。最后,将该模型及同类型模型理论曲线分别与试验曲线进行比较分析,并在此基础上探讨初始空隙闭合对脆性岩石损伤和附加损伤演化规律产生的影响。研究结果表明:该理论模型能够准确地反映脆性岩石变形破坏全过程,且能够阐释围压、初始空隙和脆性岩石峰前变形力学特性3者之间的关系,从而验证了本文模型和方法的合理性与可行性。
The constitutive model of rock materials is the basis of rock engineering design and analysis.The limi-tations that the present statistical damage constitutive model could not well reflect the mechanical properties of pre-peak deformation of brittle rocks are considered to establish a simulation method that could accurately reflect the whole process of brittle rocks deformation and failure.Firstly,the initial voids closure and its influence are studied based on the analysis of deformation mechanical characteristics of brittle rocks.Therefore,it can be divided into two types: the first type of initial voids and the second type of initial voids.The former could only be closed under hydrostatic pressure.The degree of closure affects the change characteristics of elastic modulus of brittle rocks and the unclosed part causes the initial damage of brittle rocks.The latter could be closed under arbitrary stress state and it could be completely closed at the initial macroscopic deformation stage.Both the initial compaction deformation stage and the initial macroscopic nonlinear deformation curvature are affected by the degree of closure. Secondly,brittle rocks are abstracted into two parts:fracture material and skeleton material. The method of brittle rocks deformation analysis is established based on the method of material deformation mechanics.The deformation analysis methods of fracture material and skeleton material are established respectively based on instantaneous strain and statistical damage theory and then the constitutive model of brittle rocks is established considering initial voids closure and its influence,and the methods of determining model parameters are given.Finally,the theoretical curves of the proposed model in this paper and other similar models are compared with experimental curves,and the effects of initial voids closure on the evolution of damage and additional damage of brittle rocks are discussed.The results show the theoretical model could accurately reflect the whole process of deformation a
作者
张超
陈秋南
杨期君
雷勇
ZHANG Chao;CHEN Qiunan;YANG Qijun;LEI Yong(Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring,Hunan University of Science and Technology,Xiangtan 411201,China;School of Civil Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
出处
《煤炭学报》
EI
CAS
CSCD
北大核心
2020年第3期1044-1052,共9页
Journal of China Coal Society
基金
国家自然科学基金资助项目(51878270)
湖南省自然科学基金资助项目(2018JJ3163)
湖南科技大学博士启动基金资助项目(E51858)。
关键词
脆性岩石
本构模型
初始空隙
弹性模量
非线性
brittle rocks
constitutive model
initial voids
elastic modulus
nonlinearity
