Abstract:By using an dimensional distinct element program, a model for numerical calculations is established for a goaf underground with dynamic disturbance. And then the effect of disturbance intensity on the stability of goaf underground is studied by changing the peak value of the dynamic stress wave, and the static calculation and the dynamic calculation are carried out, respectively. The analytical results demonstrate that the maximum displacement of surrounding rock is 2.98mm after goaf underground is excavated, while the maximum displacement of surrounding rock increases to 5.0mm after the dynamic loading is applied, and the amplitude of the increased displacement is proportional to the magnitude of the dynamic loading, which influences the variation of displacement, maximum principal stress, minimum principal stress distribution for surrounding rock. The second redistribution of stress field of surrounding rock occurs; and the distribution area of plastic zone is expanded significantly. The results show that Shaodong mined-out area is stable, but the support of the top and bottom should be strengthened. Several suggestions to avoid instability and subside of mined-out areas induced by blasting vibration are made.