Effect of Internal Blast on Tunnel Lining and Surrounding Soil
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ORIGINAL PAPER
Effect of Internal Blast on Tunnel Lining and Surrounding Soil M. D. Goel1
•
Shivani Verma2 • Sandeep Panchal2
Received: 6 May 2020 / Accepted: 10 August 2020 Ó Indian Geotechnical Society 2020
Abstract With the recent increase in terrorist attacks on the structures with strategic importance, detailed research intervention is required to study their behaviour under extreme loadings such as loading resulting from blast. Hence, in this investigation, three different cross sections of the tunnel with two different soil mediums are investigated under the blast loading. Herein, 3-dimensional nonlinear finite element analysis of tunnels is carried out using ABAQUS/ExplicitÒ. Stress–strain response of soil, concrete and reinforcement has been simulated using Mohr– Coulomb plasticity, concrete-damaged plasticity and Johnson–Cook plasticity material models, respectively. In this study, FE analysis is carried out to compare the damage of tunnel and surrounding soil under three different cross sections of tunnel, i.e. arched, circular and rectangular, and two soil conditions, i.e. saturated and unsaturated soil. Further, tunnel is analysed for an explosion of 100-kg TNT explosive placed at the centre of the cross section of tunnel. Response of the tunnels in terms of displacement and stress at critical locations is computed for the comparison of the results. Results indicate that the variation in cross-sectional shape and surrounding soil affects the behaviour of tunnel for the same amount of the explosive. It has been also observed that displacement in tunnel lining and soil surface is of smaller magnitude for
& M. D. Goel [email protected] 1
Department of Applied Mechanics, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra 440 010, India
2
Department of Mining Engineering, Visvesvaraya National Institute of Technology (VNIT), Nagpur, Maharashtra 440 010, India
saturated soil. Also, lower stress is observed for saturated soil for all other conditions being same. Keywords Blast loading Numerical simulation ConWep Saturated and unsaturated soil mass ABAQUS/ExplicitÒ
Introduction As availability of ground surface area has reduced for the construction of transport structure, only option available is to go underground. Under this scenario, urban cities largely depend on underground tunnels for its transport. Underground tunnels can be used for railways, roadways, water transportation, sewer lines, electrical power, routing steam or cables for telecommunication, along with connecting buildings for expedient movement of people and essential goods. Internal explosion can lead to multiple reflection phenomenon which can be more disastrous than the external explosion as destruction is more in case of internal explosion as compared to the external blast due to reason mentioned earlier, since performing experimental blast tests would not be feasible from socioeconomic point of view. Thus, numerical and analytical study of structures exposed to blast loading is highly importan
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