Application of Geophysics in Engineering Studies

A time-lapsed integrated geophysical investigation was carried out on the Mokuro Earth Dam Embankment. The main objective of the study was the assessment of the embankment for anomalous seepages. The geophysical data acquisition was carried out in three phases. The first phase involved the Magnetic, Self Potential (SP) and Resistivity methods shortly after the dam artificial lake was fully discharged and the earth dam embankment was rehabilitated. The second and third phases were carried out two weeks and three months after the dam was gated and the artificial lake was fully restored and this involved the SP and 2-D resistivity measurements only. Total field magnetic and SP data were acquired along a traverse established on the crest of the dam embankment with 5 m station interval. The corrected magnetic data were used to generate a magnetic profile. The magnetic profile was interpreted qualitatively and semi-quantitatively for target position and depth to the top of the magnetic source. The SP data were presented as profiles and qualitatively interpreted.