| Description |
The dynamic strength properties of rock have a critical application in blasting, fragmentation, designing underground structures, and perforating oil and gas wells. This research focused on two types of sandstone from Utah with two different ranges of porosity and the effect of porosity and water content on dynamic compressive and tensile strength under dynamic loading conditions. The Split Hopkinson Pressure Bar (SHPB) apparatus was used for measuring the compressive and tensile strength of these rocks. The dynamic compressive strength, measured under a strain rate of about 350/s, was found to be 1.4 to 2.0 times the compressive strength measured under static conditions for samples of similar dimensions in both dry and saturated conditions for 'red' and 'buff' sandstones. Based on these results, this research found that rock specimens with higher porosity had a higher dynamic increase factor (DIF). In addition, water reduced the cohesion of saturated rock by approximately 20%, and saturation reduced the dynamic compressive and tensile strength by approximately 20%. However, fragment sizes of saturated samples are finer than those of dry samples. The saturated samples also absorbed approximately 15% less energy. |
