Rahul Shakya; Manendra Singh; Narendra Kumar Samadhiya
Abstract
An earthquake is a random occurrence that can happen anytime in highly seismic active areas. Therefore, it might happen even when the metro-train is moving. In such a scenario, the vibrations produced by the dynamic loading of a moving metro-train and the dynamic loading due to an earthquake will impact ...
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An earthquake is a random occurrence that can happen anytime in highly seismic active areas. Therefore, it might happen even when the metro-train is moving. In such a scenario, the vibrations produced by the dynamic loading of a moving metro-train and the dynamic loading due to an earthquake will impact the dynamic response of underground metro-tunnels. In this work, an effort is made to comprehend how the Delhi Metro's underground tunnels will respond to the combined dynamic loading from the earthquake and the running train. Therefore, the dynamic response of underground metro-tunnels is primarily influenced by the vibrations generated due to the dynamic loading of a running metro-train and the dynamic loading due to an earthquake. Both these loadings cause vibrations at the ground surface and the tunnel utilities. In this paper, an attempt is made to understand the response of Delhi metro-underground tunnels to the combined dynamic loading due to the earthquake and the train's motion. Two-dimensional and three-dimensional finite element analyses are carried out using the Plaxis software. The research work finds that the overall response at the ground surface increases due to the combined dynamic loading of the train and earthquake compared to the train's or the earthquake's sole dynamic loading. Maximum displacements in the soil-the tunnel system and forces in RC liners are found to be more significant for the combined loading of the earthquake and the train motion than those due to individual loadings.
Rock Mechanics
R. Shafiei Ganjeh; H. Memarian; M. H. Khosravi; M. Mojarab
Abstract
Dynamic slope stability in open-pit mines still remains a challenging task in the computational mining design. Earthquake and blasting are two significant sources of dynamic loads that can cause many damages to open-pit mines in active seismic areas and during exploitation cycles. In this work, the effects ...
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Dynamic slope stability in open-pit mines still remains a challenging task in the computational mining design. Earthquake and blasting are two significant sources of dynamic loads that can cause many damages to open-pit mines in active seismic areas and during exploitation cycles. In this work, the effects of earthquake and blasting on the stability of the NW slope of Chadormalu mine are compared by a numerical modeling method. The dynamic results show that the maximum displacement under earthquake and blasting loads within the slope are 844 mm and 146 mm, respectively. According to the shear strain results, both the earthquake and blasting waveforms are destructive, while the earthquake waveforms cause more damages to the slope. Moreover, the deterministic and probabilistic seismic hazard analyses are carried out to assess the seismicity of the mine area. The experimental results indicate that the maximum values for the vertical and horizontal accelerations are 0.55 g and 0.75 g, respectively. The maximum calculated acceleration is then scaled to the selected earthquake accelerograms. In order to show the effective impact of the established scale, the model is executed using the original accelerograms. The results obtained show that the established scale prevents overestimation and underestimation of the displacement and strain. Therefore, applying scaled accelerograms in a dynamic slope stability analysis in mine slopes leads to more reliable and robust results. The overall results show that a strong earthquake causes plenty of damages to the slope, and consequently, interrupts the mining cycle. Hence, the seismic study and dynamic slope stability should be considered as a part of the computational mining design.
