Effects of rock weathering on guided wave propagation in rock bolts

초록

Rock quality is a critical design parameter of rock bolts. However, rock weathering deteriorates rock quality and adversely affects the performance of rock bolts. The objective of this study was to investigate variations in the velocity and predominant frequency of guided waves in rock bolts subjected to rock weathering. In experiments, chemical and mechanical weathering on 10 rock specimens was achieved with salty water and a slake durability test, respectively. The measured properties of weathered rock specimens were used in a numerical simulation model. Numerical studies on rock bolt surrounded by weathered rock mass were performed to simulate guided waves in the rock bolt. The results show that the group velocity and predominant frequency of the rock bolt decreased the weathering progressed. The grey relational grade value and importance score based on the random forest algorithm indicate that the group velocity and predominant frequency are significant factors sensitive to rock weathering. This study demonstrates that the group velocity and predominant frequency of guided waves can be useful tools for predicting rock weathering surrounding rock bolts.

키워드