Stability Analysis of Support System: A Case Study of Rukoh Dam Suppletion Tunnel, Pidie Regency, Aceh

The tunnel driving and support systems used during construction may impact the tunnel's stability. The geological strength index and rock mass rating characterized the rock mass. The empirical support system was designed using rock mass rating. At the deepest overburden, static tunnel stability evaluations were carried out using the MIDAS GTS NX finite element package (MIDAS IT Co., Ltd.). In this study, the Generalized Hoek-Brown and Mohr-Coloumb were utilized as constitutive models of rock mass and soil failure criteria, respectively. According to the outcomes of the numerical analyses conducted under static conditions, the rock masses surrounding the tunnel had more strength factors than unity. Parts of the tunnel at the inlet experienced a reduction in the rock strength factor surrounding the tunnel walls due to the construction stage. Total rock mass displacement contours around the tunnel showed more significant rock mass displacement at the tunnel walls. Stabilizing the area around the poor ground conditions is recommended to minimize the tunnel displacement brought on by the construction stage of the tunnel.