关键词: 岩土工程；崩塌；岩石振动特征；岩石稳定性；固有振动频率

Abstract: In response to the difficulty of evaluating the stability of cantilevered dangerous rock mass, the relationship between the stability of the cantilevered rock mass and the length of their rock bridges was analyzed. The formula for the relationship between the length of the rock bridge and the vibration frequency of the rock mass was given, and the theoretical calculation formula for the natural frequency of cantilevered dangerous rock mass was derived, and a stability evaluation model for cantilevered dangerous rock mass based on the dynamic index of natural frequency was established. Indoor model experiments were conducted to investigate the failure of cantilevered dangerous rock mass. It is indicated that reducing the length of the rock bridge of cantilevered dangerous rock mass will cause a decrease of its natural frequency. It is found that there are differences in the natural frequencies of different vibration modes in the stability evaluation of dangerous rock masses. The calculation formula for the natural frequency of dangerous rock masses has been adjusted with the combination of the experimental results. The experiment results demonstrate that the natural frequency of cantilevered dangerous rock mass can serve as a calculation index of stability. For the proposed experiment, the modified formula for calculating the natural frequency of cantilevered dangerous rock mass exhibits an accuracy of over 90%, in which the stability of dangerous rock mass prior to damage is calculated by the natural frequency of vibration in the vertical plane of dangerous rock mass.

Key words: geotechnicd engineering; collapse; rock vibration characterization; stability of rock mass; natural vibration frequency