ANALYSIS OF ASPECTS THAT COULD AFFECT THE AMOUNT OF CONVERGENCE AND TUNNEL STABILITY IN TUNNEL OF WATER NANJUNG

• Main Author: Rizky Fauzan, Dennas
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/47194
• Institution: Institut Teknologi Bandung

The construction of the Nanjung Water Tunnel aims to reduce the risk of flooding on the banks of the Citarum River by increasing the capacity of the original Citarum River from 570 m3 / s to 643 m3 / s so as to increase flow. In the construction of tunnels, drilling and blasting activities are carried out to destroy hard rock so that it will produce vibrations that can change the convergence value of the tunnel so that it affects the stability of the tunnel. In addition to vibration, there are also several aspects that can affect the amount of convergence values such as the tunnel face distance to the monitoring point and the rainfall intensity. If not monitored about value of a large and continuous rate of movement which, can potentially cause tunnel collapse. In this final project, tunnel stability will be analyzed by measuring convergence between two points on the walls and roof of the tunnel by using a convergencemeter and how much the influence of blasting vibrations, tunnel face distance, and rainfall intensity on convergent values. The stability analysis criteria to be used are based on the critical strain concept by Sakurai (1983) and the displacement rate recommended by UG Geotech PT Freeport Indonesia (2000). From the results of the analysis of the stability criteria, the Nanjung Air Tunnel can be said to be stable or do not have a significant buffering problem if the strain size is less than 1,026% while based on the stability criteria of the UG Geotech PT Freeport Indonesia transfer rate (2000) is divided into 5 categories namely negligible, moderate, severe, very severe, and extremely severe.