XU Tao,PENG Gongxun,LIU Jie,et al.The relationship between cross-hole seismic CT detection error and borehole distance in karst area[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2022,61(01):105-111.
XU Tao,PENG Gongxun,LIU Jie,et al.The relationship between cross-hole seismic CT detection error and borehole distance in karst area[J].Acta Scientiarum Naturalium Universitatis Sunyatseni,2022,61(01):105-111. DOI: 10.13471/j.cnki.acta.snus.2021D062.
The relationship between cross-hole seismic CT detection error and borehole distance in karst area
The geological conditions in karst areas are complex and diverse.Cross-hole seismic wave CT can be used to detect the development of karst for engineering construction. To investigate the characteristics of detection errors and factors influencing these errors, we carried out field tests in Baiyun District, Guangzhou, to detect multiple CT profiles using the same bridge pile with different borehole distances, and analyzed the relationship between the error of cross-hole seismic wave CT detection and the transmission-reception distance of boreholes.The results show that: 1) the detection error increases almost exponentially with the increase of the borehole distance, 2) the average error increases from 0.2 m to 0.7 m while the borehole distance increases from 10 m to 21 m, and 3) when the borehole distance is over 20 m, the detection of CT profile may be not reliable. Under reasonable technical parameters and test schemes, the seismic wave cross-hole CT method can accurately identify geological anomalies with a size of 1 m or more. Using currently available equipment, the appropriate CT borehole distance should be 5 to 20 m for the area of medium to slightly weathered limestone.
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