STABILITY ANALYSIS OF TWIN TUNNELS THAT ARE DUG UP TOGETHER USING CONVERGENT MONITORING IN NANJUNG
Nowadays the use of tunnels as a means for transportation is growing, due to many issues both in terms of cost and environment. In making tunnels, tunnel stability becomes very important. This is due to the quite complex conditions that exist in nature, as well as observations and interpretation...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/41605 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Nowadays the use of tunnels as a means for transportation is growing, due to many
issues both in terms of cost and environment. In making tunnels, tunnel stability
becomes very important. This is due to the quite complex conditions that exist in
nature, as well as observations and interpretation of field data that must meet the
requirements in a geotechnical study. In addition to geotechnical studies,
verification and monitoring of stability is crucial.
This research was carried out on twin tunnels located in Nanjung, Cimahi, West
Java, Indonesia. This tunnel is a tunnel that is used to divert water flow, where the
tunnel is used to increase the flow of water through the decrepit waterfall. This twin
tunnel has a distance from the center point of the tunnel is 18 meters, with a tunnel
width of 9 meters. Field RMR verification is performed at each excavation as well
as monitoring using convergence. The data used are data on STA 135, which is
considered representative. From the RMR verification in the field, the value of RMR
54 is obtained. From this RMR data, the value of c = 200-300 KPa and ? = 25o-
35o is used as a reference for the stability of tunnel stability analysis.
RS2 numerical modeling is used for back analysis by trial and error, to get the
displacement close to the actual condition. While the 3-dimensional modeling using
RS3, to get the influence of the excavation face on twin tunnels that were dug
together. From the results of RS3 modeling and based on convergent monitoring, it
shows that the face of excavation of tunnels excavated together does not affect the
stability of the tunnel for shallow tunnels (23 meters from the surface) with rock
types for the value of RMR 54. This is seen from the Strength Factor fixed at 1.3
and 1.2 in the tunnel wall for each modeling for the same and different excavation
faces. |
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