Geotechnical Stability Performance of Batubesi Dam: A Review of Seismicity Impact on Structural Dam Safety

This journal is intended to evaluate geotechnical stability performance of Batubesi Dam, a technical review of the structural safety on a concrete facing rockfill dam (CFRD) in terms of geotechnical stability of downstream slope face under different seismicity models in several determined conditions. Batubesi Dam is a hydroelectric power plant located in an operation area of PT Vale Indonesia Tbk at Sorowako, East Luwu Regency, in South Sulawesi Province, Indonesia, constructed to elevated water level of the dam reservoir to generating electric power. In the present journal, effects of seismic loading and the reservoir in two different water levels (e. g. normal water level and probable maximum flood level) are exercised to understand behavior of the dam structure against external forces. A limit equilibrium method is introduced to determine factor of safety (FoS) of respective condition, meanwhile seismicity models are obtained from previous study, references, and standards. Geotechnical models of the dam structure and its ground profiles are referring to detailed engineering design and previous geotechnical investigation related to the study area. The dam structure is modeled in effective stress condition in free-drain concept in which the porewater pressures are represented by presence of piezometric surface (phreatic lines) that confirmed by in-place geotechnical monitoring and surveillance data. In certain conditions, some safety factors of the dam are not complying with the minimum requirement (standards and/or references), further additional analysis by means of finite element method should be performed to obtain stress deformation, stress-strain relationship behavior, and potential displacement (level of damage) of the dam.