Joint Use of a Surface-Wave Method and a Resistivity Method for Safety Assessment of Levee Systems

We proposed an integrated geophysical method which can non-invasively estimate soil condition of levees in order to evaluate their vulnerabilities. The geophysical method consists of a surface-wave method using a land streamer and a capacitively-coupled resistivity method. The method is mainly performed along levees at crest or levee toe in order to delineate lateral variation of soil condition. The effective performance of field measurements using these methods is assured because sensors are not fixed on the levee surface. We have also developed a cross-plot analysis of the measured geophysical properties in order to estimate soil type in body and base of levees. We have applied the method to many levees in Japan and evaluated the applicability of the method. In conclusion, the cross-plot analysis using S-wave velocity and resistivity obtained through the surface-wave method and the capacitively-coupled resistivity method provides reliable soil information of levee body and base.