Dynamic response of cut and cover tunnel section under blast loading

• Published in: Innovative infrastructure solutions : the official journal of the Soil-Structure Interaction Group in Egypt (SSIGE) 2021-03, Vol.6 (1), Article 27
• Main Authors: Shukla, Palak J., Desai, Atul K., Modhera, Chetankumar D.
• Format: Article
• Language: English
• Subjects: Earth and Environmental Science; Earth Sciences; Environmental Science and Engineering; Foundations; Geoengineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Technical Paper
• ISSN: 2364-4176; 2364-4184
• DOI: 10.1007/s41062-020-00391-y

In the present study, three-dimensional nonlinear finite element analysis is used to investigate the dynamic response of cut and cover tunnel subjected to blast loading. The analyses are performed using a dynamic explicit analysis tool in ABAQUS. The blast load is modeled using the CONWEP blast function available in ABAQUS. The reinforced concrete section is modeled using three-dimensional solid elements and stress–strain response of concrete is simulated using a concrete damaged plasticity model. The reinforcements are modeled using three-dimensional truss elements, and material properties are simulated using a metal plasticity model with isotropic-linear-elasticity. The parametric studies have been performed to evaluate the performance of key structural elements of cut and cover facilities, i.e., top slab and walls considering (1) different cover thickness (buried depth- d ) of tunnel to height of tunnel ratio ( d / H ) (2) explosive charge weight. The mitigation measure using steel polypropylene hybrid fiber-reinforced concrete (HFRC) was also explored to improve the performance of the sections studied. It is observed from results that the displacement of tunnel increases with an increase in charge weight and decreases with an increase in d / H ratio. It can be observed from damage assessment that tension accumulation is the governing factor for the damage of reinforced concrete sections of the cut and cover tunnels and the extent of damage is observed to be reduced by increasing d / H ratio, i.e., increasing burial depth. The intermediate wall of the cut and cover section is the most critical element to avoid the progressive collapse of the structure. It is observed that the use of HFRC in the tunnel as an alternative to conventional concrete improves the blast-resistant capacity of the tunnel.