Evaluation on the Soil Flexibility of the Largest HEP Dam Area in East Malaysia using 1-D Equivalent Linear Analysis

This paper presents the evaluation of soil flexibility at vicinity Bakun HEP Dam, largest in East Malaysia. The dam is located Belaga District Sarawak, approximately 50 km from active Tubau and Bukit Mersing fault lines. area experienced earthquakes magnitudes ranging between 3.5 5.4 during period 1994 2010. study used global local earthquake records to evaluate site specific seismic hazard using a 1-D equivalent linear analysis. SPT data 15 boreholes are utilized. Soil flexibility, factor safety, liquefaction probability potential index evaluated ascertain ground settlement effects. results show that amplification 2.445 5.146, while peak accelerations (PGA) surface maximum average 0.25g PGA. factors for range 2.6 - 3.0, 2% POE years. corresponds 2475 year return period. response spectra found matching with target design Sarawak as reported Malaysia National Annex (MS EN 1998-1:2015). effects be insignificant, result nearby considered safe any settlement. highlights importance evaluating ability new or existing structures withstand up PGA case event should occur future.