Experimental Study on Compressive Strength of Soil-Rock Mixed Fillers Based on DIC Method

Through the indoor unconfined compressive strength test, focusing on the influence of different stone content and fine-grained material proportion on its compressive strength. Combined with the XTDIC analysis system to obtain the strain and displacement cloud diagrams of the sample, and the qualitative and quantitative analyses is carried out. The results show that under static loading, the increase in strain leads to an accelerated rate of initial stress growth and a significant increase in peak stress, and the maximum increase of adjacent peak stress is 22.2%, after reaching the peak, the strain continues to increase while the rate of stress reduction slows down, and the residual stress rises; when the content of stone powder in the specimen is fixed and the stone content varies, the growth rate of initial stress is accelerated and leads to the elevation of peak stress. From the stress-strain curve analysis, it can be seen that the specimen shows the best mechanical properties and the smallest deformation when the stone content is 70% and the stone powder accounts for 80%; the specimen shows the worst mechanical properties when the stone content is 30% and the stone powder accounts for 20%. The effect of fractal dimension on the unconfined compressive strength after compaction was significant, and with the decrease of fractal dimension after compaction (the increase of stone content), the unconfined compressive strength increases first and then decreases.