Effect of Seismic P-Waves Propagation on Circular Tunnels in Layered Ground
Amr Ibrahim1, Osman Ramadan2, Adel Ak3

1Amr Ibrahim, Senior Bridge/Structural Engineer, Omrania & Associates, Saudi Arabia.
2Osman Ramadan, Professor, Structural Engineering, Cairo University, Giza, Egypt. Dean, Higher Technological Institute, Tenth of Ramadan City, Egypt.
3Adel Akl, Professor, Structure Analysis and Mechanics, Cairo University, Giza, Egypt.
Manuscript received on November 22, 2019. | Revised Manuscript received on December 15, 2019. | Manuscript published on December 30, 2019. | PP: 2919-2923 | Volume-9 Issue-2, December, 2019. | Retrieval Number:  B2308129219/2019©BEIESP | DOI: 10.35940/ijeat.B2308.129219
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: During propagation of the compression seismic P-waves, the tunnels are subjected to ovaling deformations. In cases where the soil stiffness is varying along the tunnel cross-section, tunnel lining may take sharper deformed shapes and subjected to magnified bending moments and thrust forces. This paper investigates the effect of the soil stratification on the seismic behavior of circular tunnels under P-waves loading. A 2D finite element models with time history earthquake (EQ) analysis were performed accounting for different tunnel/soil interface slippage conditions. The finite element analysis results were compared with recent analytical solution for calculating the seismic forces of the tunnel lining. The study proved that soil stratification has a great effect on the tunnel seismic forces and it should be considered in the analysis and design. Illustrative curves were presented in this paper to give approximate magnification factors for the anticipated forces. It should be used as a guide in the preliminary design stage.
Keywords: Soil Stratification, Seismic P-Waves, Circular Tunnel, Earthquake Loads.