SEISMIC RESPONSE ANALYSIS OF TUNNEL IN THE LONGITUDINAL DIRECTION UNDER EARTHQUAKE LOADING USING 3D DYNAMIC ANALYSIS
In recent years, Indonesia has experienced significant population growth, leading to an increased demand for transportation systems. In major cities, limited surface land has become an issue related to transport system planning. As a potential solution, tunnel construction offers an alternative for...
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| Format: | Theses |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/86318 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | In recent years, Indonesia has experienced significant population growth, leading to an increased demand for transportation systems. In major cities, limited surface land has become an issue related to transport system planning. As a potential solution, tunnel construction offers an alternative for expanding transportation networks underground. However, Indonesia is highly prone to earthquakes, making it essential to analyze tunnel behavior under seismic loads. While most previous analyses focus on two-dimensional, transverse perspectives, this study presents a three-dimensional, longitudinal analysis using FLAC3D software. Parametric studies were conducted on six models, varying by site class (SC, SD, and SE) and earthquake load (PGA 0.1g and 0.5g). Each model employed the Mohr-Coulomb constitutive model, incorporating a damping ratio to capture the nonlinear behavior of the soil. The numerical modeling results were compared with analytical calculations. Although full convergence was not achieved in this study, there are trends found from some of the results. Stiffer soils (e.g., site class SC) tend to transmit higher forces to the tunnel structure compared to softer soils. Conversely, stiffer soils also restrict tunnel movement more effectively, resulting in smaller deformations relative to those in softer soils (e.g., site classes SD and SE). Regarding seismic loads, models subjected to a PGA 0.5g load exhibited a more pronounced impact on tunnel behavior than those with a PGA 0.1g load. Comparisons between dynamic modeling and analytical solutions revealed some similarities, but significant discrepancies were observed, particularly under the PGA 0.5g load. Additionally, the longitudinal analysis indicated that tunnel responses, in terms of deformation and internal forces, were relatively consistent. This suggests that a two-dimensional analysis may be sufficient to represent tunnel behavior for the conditions studied. Nevertheless, further analyses are required to assess the effects of varying earthquake load directions and magnitudes for a more comprehensive understanding. |
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