ANALYSIS OF TUNNEL STABILITY ON SOFT ROCKS IN TUNNEL 3 SECTION 1 SIGLI – BANDA ACEH TOLL ROAD

• Main Author: Alamsyah, Syamsi
• Format: Final Project
• Language: Indonesia
• Subjects: Pertambangan dan operasi berkaitan
• Online Access: https://digilib.itb.ac.id/gdl/view/51568
• Institution: Institut Teknologi Bandung

Sigli - Banda Aceh toll road is part of the Trans Sumatra Toll Road connecting Banda Aceh City, Aceh Besar District, and Pidie Regency. Tunnel 3 is one of the tunnels located in section 1 (Seulimeum - Padang Tiji route) on the Sigli - Banda Aceh toll road. This highway tunnel was built in the form of twin tunnels, namely tunnel 3A (towards Banda Aceh) and tunnel 3B (towards Sigli). Each tunnel has a horseshoe cross-section with dimensions of 10 m high and 12 m wide. Rock mass composing tunnel 3 area is included in soft rock. The rock types in the tunnel area are sandstones with varying degrees of weathering according to depth. Rock mass classification is carried out to obtain an estimate of the rock mass properties, determine the method of excavation, and determine the support. The research was conducted by modelling tunnel 3 using software to determine the tunnel stability. Based on existing data and the assumptions used, the analysis is focused on the value of deformation that may occur in the tunnel. The deformation values obtained from the tunnel model are expressed in terms of tunnel strain to be compared with the critical strain criterion. The results obtained show that tunnel 3A has a vertical convergence value of 13 cm - 16 cm with a strain of 1.35% - 1.65% in the unsupported condition and a vertical convergence value of 9 cm - 11 cm with a strain of 1% - 1.14% in the supported condition. Tunnel 3B has a vertical convergence value of 9 cm - 12 cm with a strain of 1% - 1.23% in the unsupported condition and a vertical convergence value of 6 cm - 7 cm with a strain of 0.62% - 0.74% in the supported conditions. Horizontal convergence was about 3 cm with a strain of less than 1% under each condition for both tunnels. The value of the strength factor contour around the tunnel ranges from 1 - 1.29 in the unsupported condition and 1 - 4.13 in the supported condition. The analysis shows that the deformation of the tunnel floor in tunnel conditions with support is an aspect that has a major influence on the value of the tunnel strain. In general, the results of the study concluded that tunnel 3 section 1 of the Sigli - Banda Aceh toll road is in a stable condition. The analysis shows that the deformation of the tunnel floor in tunnel conditions with supports is an aspect that has a big influence on the value of the tunnel strain. In general, the results of the study concluded that tunnel 3 section 1 of the Sigli - Banda Aceh toll road is in a stable condition.