道路用煤矸石路基残余剪切特性与细观行为OA

To explore the influence of water content and particle gradation on the evolution of residual shear strength characteristics of coal gangue subgrade fill and reveal the underlying mechanisms,this study employed drained repeated direct shear tests to evaluate the mechanical responses of coal gangue under varying conditions.Additionally,discrete element numerical simulations were conducted to analyze,from a mesoscopic perspective,the evolution characteristics of particle displacement fields and contact force chain networks during shearing.The results indicate that the shear stress-displacement curves of coal gangue exhibit strain-hardening behavior,which can be well fitted by a hyperbolic model.The residual shear strength decreases significantly with increasing water content,accompanied by a reduction in interparticle friction and interlocking effects.This trend is more pronounced in samples with higher fractal dimensions(well-graded).At the mesoscopic level,specimens with lower fractal dimensions are dominated by a coarse-particle skeleton with highly concentrated force chains,whereas those with higher fractal dimensions show enhanced fine-particle filling,leading to a more uniform distribution of contacts and reduced shear stability.This study elucidates the macro-mesoscopic coupling mechanisms and provides an important theoretical basis for material design and long-term stability prediction of coal gangue subgrades.