Indirect method for the quantitative identification of unstable rock

Under the influence of continuous external factors (rainfall, earthquakes, construction, etc.), slope rock masses in a stable state can gradually transition to unstable rock, which can then collapse. A safety factor can identify the occurrence of failure but cannot identify the transition of stable rock to unstable rock; thus, it cannot realise the quantitative identification of the latter. In this study, a cohesive safety factor (CSF) and a relatively objective analysis method are proposed to effectively identify unstable rock. The CSF can be calculated by the natural vibration frequency and applied as a mechanical index to characterise unstable rock; when CSF is less than 1, the rock is defined as unstable. Compared with the traditional method, the new method has the merits of simple operation, low cost and high efficiency and provides a relatively complete quantitative evaluation index and evaluation criteria for quantitative identification of unstable rock for engineers engaged in early warning and prevention of rock collapse.

Automated summary

By proposing a cohesive safety factor and a relatively objective analysis method, unstable rock can be effectively identified, providing engineers with quantitative evaluation indices and criteria.