基于DEM法的胶凝砂砾石材料宏细观破坏特征分析

Analysis of Macro-Meso Failure Characteristics of CSG Materials Based on DEM Method

【目的】探究胶凝砂砾石(CSG)材料宏细观力学特性及破坏特征。【方法】对不同水胶比(1.5、1.2、1.0)下的胶凝砂砾石材料进行室内单轴压缩试验,基于试验结果建立精细化CSG离散元(DEM)模型,采用宏-细观跨尺度结合的研究方法,探究CSG材料变形破坏特征。【结果】研究表明,当水胶比为1.0时,试件抗压强度最大,初始压密阶段最短。随着加载过程的持续,颗粒的侧向位移趋势逐渐增大,当进入裂纹发展阶段时,颗粒速度矢量出现明显的分隔线,最终发展为贯穿裂缝。整个加载过程,孔隙率表现为先减小后增大。【结论】研究成果揭示了CSG材料在不同加载阶段的力学特性及失效破坏时的宏细观特征。

[Purposes]This paper aims to investigate the macro-fine mechanical properties and damage characteristics of cemented sand gravel(CSG)materials.[Methods]Indoor uniaxial compression tests were carried out on cemented gravel materials with different water-to-cement ratios(1.5,1.2,and 1.0),and a refined discrete element model(DEM)of CSG was established based on the experimental results,and a macro-fine cross-scale combination of research methods was adopted to investigate the deformation and damage characteristics of CSG materials.[Findings]The study shows that when the watercement ratio is 1.0,the compressive strength of the specimen is the greatest,and the initial compressiondensity stage is the shortest.With the continuation of the loading process,the lateral displacement tendency of the particles gradually increased,and when entering the crack development stage,the particle velocity vector appeared obvious separating lines,which eventually developed into penetrating cracks.Throughout the loading process,the porosity showed the characteristics of decreasing and then increasing.[Conclusions]The results reveal the mechanical properties of CSG materials at different loading stages and the macroscopic and microscopic characteristics during failure damage are revealed.