Mechanical properties and failure laws of sandstone under dynamic and static combined loading conditions

In order to study the mechanical characteristics and flaw evolution damage law of sandstone containing cross-flaw under dynamic and static combined loading conditions, a one-dimensional dynamic and static combined loading test was carried out on sandstone specimens with two different cross-flaw angles using the SHPB system. This experiment aimed to analyze the dynamic mechanical properties of sandstone with varying angular flaws and the dynamic damage mode of the rock body. The results showed that under the dynamic and static combination conditions, prefabricated horizontal flaws significantly impacted the dynamic compressive strength more than prefabricated inclined flaws. The increase in the angle between two flaws initially reduced and then enhanced the dynamic compressive strength of the sandstone. The combined loading reduced the influence of inclined flaws on specimen strength. With the increase in the angle of prefabricated flaws, the dynamic compressive strength and dynamic peak-strain of rock decreased first and then increased. The artificial cross-flaw angles of 0° and 90° were mainly dominated by tensile damage, and 30°~60° by shear damage. The existence of complex prefabricated flaws has a regular effect on rock failure.