单轴压缩下裂隙倾角对花岗岩-混凝土力学行为及能量演化的影响

Influence of Crack Angles on the Mechanical Behavior and Energy Evolution of Granite-Concrete under Uniaxial Compression

为探究单轴压缩下不同裂隙倾角对花岗岩-混凝土组合体试件的强度及能量演化的影响,结合室内试验标定的细观参数,采用二维离散元颗粒流程序(PFC^(2D))对组合体试件开展了数值模拟研究。结果表明:花岗岩-混凝土的强度和变形特征受裂隙倾角影响,其强度和变形参数随裂隙倾角的增大呈逐渐增大趋势;在单轴压缩过程中,试样内部能量转化为宏观裂纹扩展,最终的破坏模式主要以拉伸失效断裂和剪切失效断裂为主;组合体试件的总能量和耗散能随裂隙倾角的增大而增大,试件破坏时总应变能大于耗散能。基于耗散能的计算,构建了损伤本构方程,当损伤因子为0.8时,试件接近极限状态,此时的能量消耗较大,显著降低了组合体试件的强度。

To investigate the influence of the crack angle on the strength and energy evolution of graniteconcrete composite specimens under uniaxial compression,a numerical simulation study was conducted using the two-dimensional particle flow code(PFC^(2D))based on the micro-parameters calibrated through laboratory tests.The research results indicate that the strength and deformation characteristics of graniteconcrete are affected by crack angles,and their strength and deformation parameters gradually increase with the increase of crack angle.During the uniaxial compression process,the internal energy of the specimens transforms into macroscopic crack propagation,and the final failure modes are mainly tensile fractures and shear fractures.The total energy and dissipated energy of the composite specimens increase with the increase of crack angle,and the total strain energy is more than the dissipated energy when the specimens are damaged.Based on the calculation of dissipated energy,a damage constitutive equation was constructed,indicating that when the damage factor reaches 0.8,the specimen is already close to its limit state,resulting in significant energy consumption and a decrease in the strength of the composite specimen.