BACK ANALYSIS OF THE SWELLING PHENOMENA IN DIVERSION TUNNEL USING TWO-DIMENSIONAL MODEL

• Main Author: Ihsan Batu Bara, Muhammad
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/76763
• Institution: Institut Teknologi Bandung

In the process of constructing diversion tunnel, the project team encountered a swelling phenomenon which was indicated by deformation and rock crushing. For this reason, a back analysis was carried out to determine the condition of the deformed rock mass and to analyze additional strengthening methods to prevent the swelling phenomenon in the tunnel. In this study, two-dimensional numerical modeling was carried out to further determine the value of the deformation modulus (E) and swelling pressure using iterations. The results of these iterations are used as the actual conditions of the tunnel for analysis of additional strengthening methods in the form of forepoling and invert beams. The numerical iteration produced a percent strain of 11.11% and after installation of forepoling to form a 90o circular arc resulted in a percent strain of 0.37%, installation of forepoling to the spring line resulted in a percent strain of 0.31% and the installation of forepoling of the roof to the tunnel wall produced a percent strain of 0.26% so it was concluded that the three support recommendation methods gave positive results for tunnel reinforcement.