Articles | Volume 15, issue 4
Research article
24 Apr 2015
Research article |  | 24 Apr 2015

Levee reliability analyses for various flood return periods – a case study in southern Taiwan

W.-C. Huang, H.-W. Yu, and M.-C. Weng

Abstract. In recent years, heavy rainfall conditions have caused disasters around the world. To prevent losses by floods, levees have often been constructed in inundation-prone areas. This study performed reliability analyses for the Chiuliao First Levee in southern Taiwan. The failure-related parameters were the water level, the scouring depth, and the in situ friction angle. Three major failure mechanisms were considered: the slope sliding failure of the levee and the sliding and overturning failures of the retaining wall. When the variability of the in situ friction angle and the scouring depth are considered for various flood return periods, the variations of the factor of safety for the different failure mechanisms show that the retaining wall sliding and overturning failures are more sensitive to the change of the friction angle. When the flood return period is greater than 2 years, the levee could fail with slope sliding for all values of the water level difference. The results of levee stability analysis considering the variability of different parameters could aid engineers in designing the levee cross sections, especially with potential failure mechanisms in mind.

Short summary
For Chiuliao first levee, the slope sliding failure is the most likely mode to occur under all flood water level heights. However, the levee may undergo foundation sliding failure with a water level difference coefficient of 0.25 to 0.3 over a long flood return period. This is because of the high water levels and large local scouring depths. Therefore, the updated levee design cross section with rows of piles and thickened backfill material was designed to overcome possible failure modes.
Final-revised paper