Monitoring of the excavation damaged zone (EDZ) by geophysical methods during the test tunnel excavation at a depth of 140 m and 250 m

Kubota, Kenji*; Kondo, Keiji; Sakakibara, Junichi*

To evaluate the excavated damaged zone (EDZ) is one of the important factors to conduct high level radioactive waste disposal. We have conducted resistivity and acoustic tomography to evaluate EDZ during the excavation of the test tunnel at a depth of 140 m and 250 m. As a result, a few meters extent of high resistivity and low P-wave velocity zone were detected at a depth of 140 m. This suggests that EDZ by excavation of horizontal tunnel was estimated by resistivity and acoustic tomography. On the other hand, high resistivity zone were not detected at a depth of 250 m.