Reliability-based design of earth-fill dams to mitigate damage due to severe earthquakes

This paper deals with a strategy for the maintenance of geotechnical structures such as earth-fill dams. Standard penetration test (SPT) N-values are frequently used to determine the soil parameters. For this purpose, a statistical model for the N-values is firstly determined from sounding test results. In this research, however, Swedish weight sounding (SWS) tests are employed as they are simpler than SPTs. The identification of spatial correlation of the soil parameters is very difficult, since the number of sampling points is very limited to model the spatial variability. SWS is advantageous, compared with other major sounding method to identify the spatial correlation structure inside the geotechnical structures, since it makes spatially short-interval exams possible due to its simplicity and compactness. Based on the statistical model for the N-values, the shear strength parameters are derived through the empirical relationships. Then, a reliability analysis of the embankments is conducted considering the variability of the internal friction angle and the seismic hazard. Consequently, the probability of damage to the earth-fill over the next 50 years is calculated, and the effect of improving the earth-fill is evaluated based on this probability.