| Coal mine goaf,underground caves and other ground collapse,damage to urban infrastructure,endangering the safety of people’s lives and property.With the exploration,development and utilization of underground space in China,the demand for fine imaging of underground hidden voids is increasing.The micro-motion exploration uses the weak vibration of the surface to image the shear wave velocity structure of underground medium.With its advantages of environmental protection,non-destructive,flexible,efficient and low cost,it has been widely concerned and applied in underground space exploration.Based on the above reasons,the combined imaging method of SPAC and HVSR was carried out in this paper,and the detection ability of hidden underground cavities was analyzed and evaluated.In order to facilitate the discussion on the detection effects of underground cavities with different buried depths,a linear observation array was set up at20 m,100m and 200 m above the underground tunnel as the detection target,and the shear wave velocity profiles obtained by fretting SPAC,HVSR and joint imaging methods were compared to carry out the research on the fretting detection methods of underground concealed cavities and the effect evaluation.The results show that the detection effect of SPAC and HVSR is similar to that of the combined imaging method at 20 m depth,while the detection results of the survey line at 100 m and 200 m indicate that the combined imaging method of SPAC and HVSR is superior to that of SPAC and HVSR for underground cavity detection. |
