Impact of Tunneling Running Side-by-Side to An Existing Tunnel on Tunnel Performance using Non-linear Analysis | ||
| The International Conference on Civil and Architecture Engineering | ||
| Article 13, Volume 7, 7th International Conference on Civil and Architecture Engineering, May 2008, Pages 299-308 PDF (490.59 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/iccae.2008.45460 | ||
| Authors | ||
| S. A. Mazek; E. M. El-Tehawy | ||
| Lecturer, Ph. D., Civil Engineering Department, Military Technical College. Cairo. | ||
| Abstract | ||
| During construction of twin tunnels running parallel side-by-side, there are Geotechnical concerns due to tunneling near annex structures. One of these concerns is occurred as a new tunnel is constructed side by side to an existing tunnel. The serious damage in the existing tunnel liner is predicted and the maximum radial displacement of the existing tunnel is also computed. In the present study, the prediction of the tunnel system performance under the impact of the new constructed tunnel running side by side to the existing tunnel is highlighted and a model is proposed to study the soil structure interaction using a 2-D finite element analysis. The horizontal separation between the twin tunnels is also studied so as to ascertain the zones of influence. The study presents a case history along El-Azhar road tunnel to assess the accuracy of the proposed finite element model. Based on this case history, extensive study using the finite element model is conducted to predict the performance of the tunnel system under the twin tunnel construction. The constitutive model for this analysis contains elasto-plastic materials. A yielding function of the Mohr-Coulomb type and a plastic potential function of the Drucker-Prager type are employed. A linear constitutive model is employed to represent the tunnel liners. At the case study, the study presents comparison of the results obtained by the field measurements and those obtained by the finite element analysis. There is a good agreement between computed and measured values. The tunnel system performance is expressed in terms of settlement and radial deformation in the existing tunnel under the twin tunnel construction. The study includes the prediction of the settlement, the relative movements, and the lining stress under construction processes. The horizontal separation between the twin tunnels is varied so as to determine the zones of influence. The horizontal separation between the twin tunnels has a significant effect on the existing tunnel movement due to the new tunnel construction parallel side by side to the existing tunnel. | ||
| Keywords | ||
| Tunnels; Tunneling; Settlement; numerical modeling and analysis; nonlinear displacement; design; Deformations | ||
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