The shear strength vibration degradation of the rock discontinuities is of great significance to analyze and evaluate the dynamic stability of rock slope. Based on the rock dynamic test

the strength vibration degradation coefficient equation of the rock discontinuities affected by multiple factors was obtained. Then

combined with the limit equilibrium theory and the principle of dynamic vector method

the UDEC program was used for calculation

and its built-in Fish language was used to program to update the strength characteristic parameters of the rock discontinuities in real time and capture the seismic inertia force of slope at any time of earthquake duration

and the minimum average safety coefficient method was adopted to solve the final dynamic stability evaluation index. Thereby

a dynamic algorithm of slope dynamic stability coefficient considering the strength vibration degradation of the rock discontinuities was proposed. The results show that: (1) The strength vibration degradation coefficient of the rock discontinuities is a dynamic variable that depends on the response value of the number and amplitude of cyclic shearing and the relative motion speed between rock blocks. (2) The algorithm is applied to the calculation example of the dynamic stability of slope with the through-type and straight rock discontinuities. The analysis results show that in the dynamic action time history

the attenuation of the dynamic stability coefficient of slope considering the strength vibration degradation of the rock discontinuities is more obvious than that without considering the effect

i.e. the calculation results of the former are more in line with the actual observation

which verify the feasibility of the proposed algorithm. (3) The minimum strength vibration degradation coefficient of the rock discontinuities decays gradually in the form of negative exponential function with the time-history change of dynamic excitation. The larger the initial cohesion (internal friction angle) of the rock discontinuities is

the smaller the slope angle (layer inclination) or dynamic load amplitude (frequency) is

the larger the minimum dynamic stability coefficient of slope during the earthquake duration is

and the relatively stronger the final dynamic stability of slope is at this time.