颗粒离散元岩石模型的宏细观抗拉强度关联  

MACRO-MICRO SCALE TENSILE STRENGTH CORRELATIONS FOR PARTICLEDEM BASED ROCK MODELS

作　　者：谭鑫[1,2] 胡跃刚 尹心 曹文贵 Tan Xin;Hu Yuegang;Yin Xin;Cao Wengui(College of Civil Engineering,Hunan University,Changsha 410082,China;Key Laboratory of Building Safety and Energy Efficiency of Ministry of Education,Changsha 410082,China)

机构地区：[1]湖南大学土木工程学院,长沙410082 [2]湖南大学建筑安全与节能教育部重点实验室,长沙410082

出　　处：《力学学报》2024年第5期1411-1425,共15页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(52278348);湖南创新型省份建设专项(2019GK1010)资助项目。

摘　　要：颗粒离散元数值模型由于具有反映材料宏细观力学特征的天然优势,而被大量学者采用开展岩石力学课题相关研究,但DEM数值模型涉及的跨尺度关联和参数标定问题给研究者带了挑战,且尚未形成获得统一认可的定量分析方法.基于规则排列的圆形颗粒DEM岩石试件拉伸模型,开展细观接触破裂模式与宏观拉伸破坏强度相关性的力学分析,指出岩石试样宏观抗拉强度取决于内部细观接触破裂模式,而细观破裂模式则受到接触抗拉强度、接触抗剪强度、接触法向刚度、接触切向刚度,甚至颗粒大小及排列方式的共同影响.根据理论分析及数值模拟结果提出了4种细观破裂模式及相应宏观抗拉强度理论计算公式,并将公式修正应用于随机颗粒排列的类岩石材料DEM模型,从细观角度揭示了宏观DEM岩石材料拉伸破坏机理,构建了宏细观抗拉强度参数关联.所建立关联公式的合理性得到了大量随机数值模拟结果的有效验证,可为研究者利用颗粒DEM数值模型进行岩石和混凝土等类脆性材料模拟的参数选取及标定工作提供重要的参考依据.The discrete element method(DEM)numerical model has gained significant attention from scholars in the field of rock mechanics research due to its ability to capture both macroscopic and microscopic mechanical characteristics of natural rocks.However,researchers face challenges when it comes to scale bridging and parameter calibration in numerical simulation studies based on DEM.Furthermore,the absence of a unified and widely accepted quantitative analysis method adds to these challenges.To address these issues,we conducted a comprehensive study using a DEM model consisting of circular particles arranged in a regular pattern.The aim was to analyze the mechanical correlation between microscopic contact failure modes and macroscopic tensile strength.Our findings indicate that the macroscopic tensile strength of rock specimens is influenced by the underlying microscopic contact failure modes.These failure modes are affected by various factors including contact tensile strength,contact shear strength,contact normal stiffness,contact tangential stiffness,particle size,and arrangement.Through rigorous theoretical analysis and extensive numerical simulations,we proposed four microscopic failure modes along with corresponding theoretical formulas for calculating the macroscopic tensile strength.To validate the effectiveness of these formulas,we applied them to DEM models of randomly arranged particles.By adopting a microscopic perspective,we uncovered the underlying mechanisms of macroscopic tensile failure in DEM rock-like materials and established a correlation for the parameters governing macroscopic tensile strength.The validity of our established correlation formulas was successfully verified through a large number of random numerical simulation results.This work serves as an important reference for researchers involved in selecting and calibrating parameters for simulating brittle materials such as rocks and concrete using particlebased DEM numerical models.By providing insights into the microscopic behavior of mate

关 键 词：离散元 岩石 破裂 宏细观 抗拉强度 

分 类 号：TU45[建筑科学—岩土工程]