It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the mi...It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters.展开更多
基于颗粒离散元计算架构建立单矿物石英岩的颗粒簇模型(grain based model,GBM),以石英岩微裂纹发展规律为约束优化矿物模型的弹性模量及其边界强度参数,开展热-固耦合下石英岩的高温损伤及强度劣化细观机理研究,获得以下结论:(1)优化...基于颗粒离散元计算架构建立单矿物石英岩的颗粒簇模型(grain based model,GBM),以石英岩微裂纹发展规律为约束优化矿物模型的弹性模量及其边界强度参数,开展热-固耦合下石英岩的高温损伤及强度劣化细观机理研究,获得以下结论:(1)优化矿物弹性模量及其边界强度参数后可很好地再现石英岩高温作用下微裂纹演化规律:首先从石英晶粒边界萌生,逐渐扩展至晶粒内部,最终形成裂纹网络。(2)单轴压缩模拟中石英岩弹性模量随温度的升高总体上呈现出先增大后减小的趋势,泊松比表现为先减小后增大,且泊松比较弹性模量对热损伤表现出更高的敏感性。(3)随着温度的升高,石英岩单轴压缩过程中微裂纹的离散性增加,破坏模式从多斜面剪切破坏逐渐转变为无明显宏观裂纹的分散式拉伸(劈裂)破坏。(4)岩石的力学强度劣化规律与其本身的致密性及矿物成分、含量密切相关,与花岗岩相比石英岩热损伤温度阈值高,约为200℃。(5)3种不同石英含量的岩石的热损伤结果表明:矿物边界和力学强度较低的矿物内部首先发生热破裂,矿物之间的镶嵌结构对石英矿物的热损伤有抑制作用。展开更多
基金Projects(51474251,51874351)supported by the National Natural Science Foundation,China。
文摘It is important to calibrate micro-parameters for applying partied flow code(PFC)to study mechanical characteristics and failure mechanism of rock materials.Uniform design method is firstly adopted to determine the microscopic parameters of parallel-bonded particle model for three-dimensional discrete element particle flow code(PFC3D).Variation ranges of microscopic of the microscopic parameters are created by analyzing the effects of microscopic parameters on macroscopic parameters(elastic modulus E,Poisson ratio v,uniaxial compressive strengthσc,and ratio of crack initial stress to uniaxial compressive strengthσci/σc)in order to obtain the actual uniform design talbe.The calculation equations of the microscopic and macroscopic parameters of rock materials can be established by the actual uniform design table and the regression analysis and thus the PFC3D microscopic parameters can be quantitatively determined.The PFC3D simulated results of the intact and pre-cracked rock specimens under uniaxial and triaxial compressions(including the macroscopic mechanical parameters,stress−strain curves and failure process)are in good agreement with experimental results,which can prove the validity of the calculation equations of microscopic and macroscopic parameters.
文摘基于颗粒离散元计算架构建立单矿物石英岩的颗粒簇模型(grain based model,GBM),以石英岩微裂纹发展规律为约束优化矿物模型的弹性模量及其边界强度参数,开展热-固耦合下石英岩的高温损伤及强度劣化细观机理研究,获得以下结论:(1)优化矿物弹性模量及其边界强度参数后可很好地再现石英岩高温作用下微裂纹演化规律:首先从石英晶粒边界萌生,逐渐扩展至晶粒内部,最终形成裂纹网络。(2)单轴压缩模拟中石英岩弹性模量随温度的升高总体上呈现出先增大后减小的趋势,泊松比表现为先减小后增大,且泊松比较弹性模量对热损伤表现出更高的敏感性。(3)随着温度的升高,石英岩单轴压缩过程中微裂纹的离散性增加,破坏模式从多斜面剪切破坏逐渐转变为无明显宏观裂纹的分散式拉伸(劈裂)破坏。(4)岩石的力学强度劣化规律与其本身的致密性及矿物成分、含量密切相关,与花岗岩相比石英岩热损伤温度阈值高,约为200℃。(5)3种不同石英含量的岩石的热损伤结果表明:矿物边界和力学强度较低的矿物内部首先发生热破裂,矿物之间的镶嵌结构对石英矿物的热损伤有抑制作用。
