Experimental Study on Dynamic Mechanical Properties of Sandstone Under Different Damage Degrees

To investigate the effects of impact loads during drilling under various geostress conditions on rock damage characteristics, strength properties, and energy absorption in geotechnical engineering, dynamic uniaxial and dynamic triaxial compression experiments were conducted on sandstone specimens subjected to different impact loads using a self-designed drilling experimental bench. The results indicate that the compressive strength of rock specimens is inversely related to the impact power during drilling; higher impact power results in lower compressive strength. Additionally, the fragmentation mode of rocks after dynamic uniaxial and triaxial compression experiments is influenced by energy absorption, with greater energy absorption leading to smaller fragment sizes post-failure. Key factors affecting rock energy absorption include the intensity of dynamic loading, with higher loading intensity resulting in increased energy absorption; the level of damage sustained by the rock itself, with greater damage causing more energy absorption during dynamic loading; and the confining pressure, with higher confining pressure leading to reduced energy absorption. This study effectively evaluates the deformation characteristics, strength properties, and energy absorption characteristics of damaged rock under impact loads. It provides valuable guidance on the stability and damage conditions of surrounding rock during the rock drilling process in the field of geotechnical engineering.