A Case Study on Buckling Stability of Piles in Liquefiable Ground for a Coal-Fired Power Station in Indonesia

Abstract

This paper discusses a case study on the assessment of buckling stability of piles due to liquefaction of foundation soils for a coal-fired power station (CFPS) in Indonesia. As the rapid growth in the economy sector, the demand for electricity is increasing and a CFPS is planned and constructed in Central Java. During the planning stage, the risk caused by earthquakes should be considered. As the foundation soils of the site consist of soft sandy silts or clays interbedded with loose fine sands up to a depth of 9 m, soil liquefaction and its effect on the buckling stability of piles for CFPS thus become the main concerns of this project. Liquefaction analysis is performed based on a SPT-N approach. A depth-weighted procedure is applied for the assessment of liquefaction potential for the site. Results of liquefaction assessment indicate the site is prone to risk of soil liquefaction due to the design earthquake. Buckling of piles due to seismic loading is evaluated for the cases of liquefied soils in both dry and wet seasons, while only the wet season scenario is the main focus of this paper. A buckling stability index is adopted as the difference between the critical pile length for buckling and the unsupported pile length due to soil liquefaction. If is greater than zero, then the pile is safe; otherwise, the pile will buckle. Results of buckling assessment show for the piles of the site with an average value of 15 as the foundation soils are liquefied during the design earthquake with magnitude of 6.8, indicating the pile foundation of the CFPS should be safe from buckling failure due to soil liquefaction.