This research deals with the maintenance strategy of geotechnical structures such as earth-fill dams and river embankments. To determine the soil parameters, the standard penetration test (SPT) N-values are frequently used. Firstly, a statistical model for the N-values is determined from sounding test results. In this research, Swedish Weight Sounding (SWS) tests, simpler than SPT, are employed. Secondly, an indicator simulation is conducted to interpolate the spatial distribution of the N-values, and the results are utilized to find degraded areas inside the embankments and to maintain the embankments. Based on the statistical model for the N-values, the shear strength parameter is derived through the empirical relationships, and then a reliability analysis of the embankments is conducted considering the variability of the internal friction angle. Finally, the effect of improving the embankments is discussed, comparing the calculated risks of the original state with the improved and restored state.