Study on fracture stability analysis of toppling perilous rock

The unstable rock aggregates with complex genetic relation is the basic condition to make large collapse disaster, the sudden destruction of any rock block in the aggregates can release energy which will spread around to produce excitation effect and the excitation signal can be characterized by excitation acceleration. For the falling perilous rock, the probability statistical features are analyzed through the indoor model test. The results show that the energy released by the unstable rock has the characteristic of point load, the probability density of excitation signal showing a single peak approximates a normal distribution, and the peak intensity in the horizontal is greater than that in the vertical; the average value, the valid value and the standard deviation value of the excitation signal is greater as it closer to the vibration source and the measuring value of the vertical direction is greater than that in the horizontal direction; excitation signal has obvious autocorrelation and it indicates that the dependence of the excitation signal to the time is more obvious as the autocorrelation factor gets bigger, and the autocorrelation factor in the vertical direction is larger than that in the horizontal direction; the completeness of the interface between perilous rocks significantly affect the excitation signal transmission, the peak of the statistical characteristics and the probability density of the excitation signal is greater as the completeness gets better, and the transfer effect of the excitation signal is better as the attenuation time gets longer. The study result has positive significance to the reveal of failure mechanisms of the unstable rock mass.