TUNNEL STABILITY ANALYSIS ON WEAK ROCKS AT TUNNEL #4 KERETA CEPAT JAKARTA-BANDUNG CONSTRUCTION PROJECT

• Main Author: Anderson, Glenn
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/51530
• Institution: Institut Teknologi Bandung

Tunnel construction is widely used in the construction of civil infrastructure, such as for railroads. In the construction process, it is not uncommon to find geological conditions that require special attention, for example, weak rock conditions or complex structures. Given the high potential for losses in the event of failure in civil tunnels, it is necessary to analyze the stability of the tunnel. This research was conducted at the inlet section of Tunnel # 4 of the Kereta Cepat Jakarta-Bandung project, where an analysis of stability of the existing design is needed to ensure that the design is safe for this project. This study analyzes the stability of the tunnel by empirical calculations and numerical modeling using the Rocscience2 software. The factors that are considered in empirical calculations are the safety factor at stage 1 and stage 2 of the supporting design and the suitability of the support material used to the country regulations. In numerical modeling, an analysis of strength factor, displacement, strain, and yielding zone values is carried out in the cross-section made based on the geological map. In addition, another scenario is created where the supports is not installed to see how much influence the support on Tunnel # 4 is to its stability. The safety factor results obtained from empirical calculations are 1.9 for the initial support stage and 5.8 for the final support stage, so we can conclude that the tunnel is in the safe category with the specifications of the support material used is in accordance with applicable regulations. Then from the numerical modeling results, the stability of the tunnel design is also in the safe category with the strength factor value of at least 1.02 and no point in the tunnel has crossed the critical strain limit, however the plastic zone area is still considered wide, so pre-support is required prior to excavation.