EVALUASI DAN DESAIN PERBAIKAN DINDING PENAHAN TANAH TIPE DINDING GRAVITASI DI CIKUPA, TANGERANG, BANTEN

Abstract

Gravity-type earth retaining wall in a factory area in Cikupa, Tangerang, Banten was found to move, resulting in cracks as large as 4 cm on the wall and the drainage channel behind the wall. Thus, this paper tries to investigate the cause of the wall movement through field observation and an analytical approach. The analytical approach was carried out using conventional and numerical methods to evaluate the external and global stabilities of the wall. The external stability analyses were performed using the conventional method and consisted of checking the wall overturning, sliding stabilities, and soil bearing capacity. Meanwhile, for the numerical approach, the finite element method was used to evaluate the global stability of the wall. The Mohr-Coulomb material model was used to simulate the stress-strain behavior of the soils in the finite element analysis. It was then found during field investigation and through the numerical simulation that the existing wall moved laterally, indicating that it experienced sliding failure. Furthermore, the analysis results also show that the existing wall design did not meet the safety criteria against external stability, especially sliding stability, bearing capacity, and global stability. It was mainly due to the poor fill material and poor foundation soil that was probably not identified during the initial soil investigation. Thus, a thorough wall repair was required to secure the adjacent warehouse. The suggested method to repair the wall is to replace the existing wall with a cantilever retaining wall system supported by bored piles, followed by replacing the fill material. A pile wall placed behind the new retaining wall was also necessary to protect the adjacent warehouse during the new wall construction. Eventually, this paper was expected to give an understanding to the readers about the importance of detailed soil exploration before construction and following the design guideline in designing any geotechnical structures.