Effect of a circular tunnel on ground response during earthquake

• Main Author: Nguyen, Minh Khoi
• Other Authors: Budi Wibawa
• Format: Final Year Project
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/75321
• Institution: Nanyang Technological University

This report describes the simulation of the dynamic response of ground surface using PLAXIS 2016 software. The objective of this project is to investigate the impact of size and location of a circular tunnel located in the ground subjected to earthquake loading. To analyze the horizontal peak displacement, horizontal peak ground velocity (PGV) and horizontal peak ground acceleration (PGA) of several points on the ground surface during the earthquake, various sizes, locations of circular tunnel will be simulated using PLAXIS 2D. A soil model of 300 m in width and 50 m in height including 2 layers of soil: loose sand and granite is adopted in this simulation study. The seismic inputs in this project involved acceleration data of the California Earthquake happened in the United States of America in 2014. Dynamic response of the ground surface when tunnel size and location vary will be analysed and compared with the case of no tunnel in the soil model. It was observed that with the existence of a tunnel at the middle of the model, its projection onto the ground surface experience the highest acceleration. The further the point is from the tunnel, the smaller its horizontal PGA. Moreover, the tunnel of 4 m in diameter showed the highest horizontal PGA and horizontal PGV. Meanwhile, the simulation results showed that the peak value of horizontal PGA was obtained when the tunnel depth was around 7.5 m, h/H = 0.25, where h is the depth of tunnel and H is the depth of the loose sand layer.