Research On Dynamic Response Random Characteristics Of Fine Sandstone Blocks Under Shock Disturbance

With the increase of mining depth and strength,the geological environment becomes particularly complex,which has caused sharp increase and enhancement in dynamic disasters.Mining disturbances like roof fracture,fault movement,roof caving,drilling and blasting will cause a severe vibration of seam roof.Adopting the analytic method in the time domain and the frequent domain in this paper,expriment study on dynamic response of roof fine sandstone was carried out,and the dynamic response random characteristics for fine sandstone was described by dimensionless quantities of relative mean value deviation factor.These results show that the fine sandstone rock excitation has good linear correlation with its response transfer in the 10 ~ 100 Hz frequency range;Under the condition of random shock disturbance,the power transfer ratio is less than acceleration transfer ratio in terms of discrete degree,which show that it's more stable by using power transfer ratio than acceleration transfer ratio to evaluate dynamic characteristics of fine sandstone;The results are similar in value,compared single frequency point with a narrow frequency band of relative mean value deviation factor for excitation transfer ratio and response transfer ratio of fine sandstone.As the volume increases,it's clearly that power spectral density transfer ratio increases at the same peak frequency,and the means of relative mean value deviation factor for power transfer ratio have a little difference.This paper has analyzed randomness of fine sandstone frequency response.Based the research results,it can give some reference to the dynamic research on coal structures in deep stope.