Effect Of Joint Surface Contact Area On Stress Wave Attenuation Under Static Load

Deep rock mass is in a high stress environment,and under the long-term geological action,a large number of weak planes and faults and fillings are formed in the deep rock mass.When the external dynamic disturbance propagates in the form of stress waves in the deep rock mass,the existence of high stress and joints makes the stress wave propagation characteristics in the deep rock mass extremely complex.The dynamic mechanical characteristics of deep rock mass with joints are studied.Geotechnical engineering such as mine safety is of great significance.This paper chooses 822 working face of Yuandian No.1 Coal Mine in Huaibei Mining Area as a sample,and studies the dynamic mechanical properties of jointed coal samples under different static loads based on the SHPB device of dynamic and static combined loading.The research results are as follows:(1)Under different axial pressures(0MPa?2MPa?4MPa?6MPa?8MPa),the maximum stress of all kinds of coal samples increases with the increase of axial pressures;under the same stress,the strain decreases with the increase of axial pressures;with the decrease of contact area,the maximum stress decreases correspondingly;under the same axial pressures,the maximum stress decreases with the increase of contact area of the sample combination.The joint closure deformation increases with the increase of stress,and increases with the decrease of contact area under the same stress and the same axial compression.(2)With the increase of axial compression,the seismic wave quality factor of each specimen tends to increase;under the same axial compression,the seismic wave quality factor decreases with the decrease of the contact area ratio;for the same contact area ratio,the value increases with the increase of the axial compression;and the transmission coefficient increases with the increase of static load,under the same static load,the transmission coefficient of the sample increases with the increase of the contact area ratio.Figure [40] table [3] reference [72]...