The Evaluation of Soldier Pile Reinforcement for the Church Building Wall Due to Ramp Foundation Excavation Works

Abstract

The construction of the Jakarta Gelora Marriott Hotel encountered technical challenges during the excavation of the ramp foundation, which was located in close proximity to an existing church building. This site constraint posed potential risks to the stability of the church foundation, thereby necessitating the implementation of a reinforcement method. The purpose of this study is to evaluate the performance of soldier piles as retaining walls in resisting lateral earth pressures induced by excavation, with emphasis on safety factor, deformation, and lateral displacement.

The research was conducted using a quantitative approach through numerical modelling with the PLAXIS software. The input data included soil investigation results, soldier pile geometric parameters, and the uniform load of the church structure obtained from ETABS modelling. The analysis was carried out in reference to SNI 8460:2017, SNI 1726:2019, SNI 2847:2019, and SNI 1727:2020. The soil profile consisted of medium-to-high plasticity silty clay at depths of 0–9 m, and low-plasticity sandy silt at depths of 9–27 m.

The findings indicated that the soldier pile was subjected to significant internal forces during excavation. A short-term (plastic) analysis was performed for an excavation depth of 3 m. The maximum deformation obtained from the second excavation stage was 56.59 mm, while the total lateral displacement reached 58.19 mm. These values exceeded the allowable deflection limit of 40 mm. Conversely, the safety factors for the first and second excavation stages were 4.2 and 3.2, respectively. These results demonstrate that the soldier pile system satisfied the safety requirements, as the minimum acceptable safety factor is 2.