岩石冲击实验碎屑分类及其分形特征

利用分离式霍普金森压杆实验系统,进行一系列的不同长径比砂岩冲击实验。对试验碎屑采用不同方法提取其信息,包括对粒径小于0.075mm的颗粒采用激光粒度分析仪。对受载后岩样破碎块度进行筛分统计,得到了该加载条件下岩石破碎的粒度分布。在此基础上,进一步计算相应破碎块度的分形维数,分别探讨了不同的长径比对分维数的影响。结果表明,砂岩破碎分维值在1.54到2.49之间,分维愈大,其粒度愈细。相同长径比岩石试件,岩石破碎分维值与试样的应变率线性相关,随应变率增大而增大。

Classification and Fractal Characteristics of the Fragments from Impacting Experiment of Rock

A series of impacting experiment on sandstone samples with different length-diameter ratios were made by SHPB(Split Hopkinson Pressure Bar) test system.The information of the fragmental rock from impacting experiment was extracted with different methods,including testing the particles less than 0.075 mm by laser particle size analyzer.The size distribution of fragmental rock was obtained through screening and statistics of rock samples fragmented under different impact load.On the basis of these,the fractal dimensions of the size distribution of fragmental rock were calculated,and effect of different length-diameter ratios on the fractal dimension was investigated.The results showed that the fractal dimension of the size distribution of fragmented sandstone ranged from 1.54 to 2.49,and larger the value of the fractal dimension was,smaller the particle size was.For rock sample with same length-diameter ratio,the values of fractal dimension were related with strain rate,the fractal dimension increased with increasing in strain rate of rock sample.