Dynamic Characteristics of Saturated Water Red Sandstone Under Different Stress Waveforms
The stress wave amplitude value and the space-time evolution law of energy dissipation significantly impact the rock-breaking effect,which is often neglected in preventing and controlling rock burst and coal and rock dynamic disasters.To study the impact of the shape of shock pulse on the dynamic characteristics of rocks,a split Hopkinson bar experimental system (SHPB) was used to conduct dynamic compression tests on dry and saturated red sandstone at different strain rates(128.88 s-1～711.31 s-1) using a variety of length (200,300,400,500 mm) and spindle-shaped impact bars (bullets).Based on the test results,it is found that the duration of the stress wave has a significant impact on the strain rate and dynamic strength of the rock.When the length of the impact bar is greater than 300 mm,the strain rate-time history curve has a "double peak" phenomenon,and the dynamic strength of the rock has a linear relationship with the duration.When (ε·)<300 s-1,the transmission energy increases with the increase of strain rate .When (ε·)>300 s-1 and the length of the impact rod is greater than 300 mm,the transmissivity of the rock decreases with the increase of the strain rate,while the dissipated energy increases with the increase of the strain rate.
stress wavelength of timeSHPBdynamicsred sandstone
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