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Title: Evaluation of Different Seepage Treatment Methods in Railway Tunnels Case Study: Addis Ababa Light Rail Transit System (LRT)
???metadata.dc.contributor.*???: Dereje, Tesfu
Keywords: Seepage Treatment Methods;Railway Tunnels;GeoStudio SEEP/W
Issue Date: Mar-2016
Publisher: Dereje Hailu (PhD)
Abstract: This research investigated and evaluated water blocking techniques in tunnel sections present at the St. Georgis tunnel using 2D modelling by numerical simulation software namely GeoStudio. With the help of GeoStudio extension, GeoStudio SEEP/W, the tunnel geometry along with material property of the concrete and backfill material using readily available hydraulic property as an assumption was modelled. This together with simplifying assumptions such as material homogeneity and isotropy, maximum water flux or infiltration pressure was seen at tunnel bottom of the side wall and clearly seen much like the actual condition. With this assumptions, the model showed that, the tunnel section exhibits maximum flux or infiltration in the bottom corner each side. The inner lining of the tunnel in particular have been studied and results show that the nodes exhibit water infiltration occurs in each node point with the maximum 9.75E -05 3 m /s. Proper application of water proofing helps in preventing water infiltration throughout the tunnel lining. Even if exterior waterproofing is part of the solution, it is also necessary to implement a drain pipe at the bottom of the tunnel to remove the water that will accumulate near the tunnel bottom. One additional finding here would be that the protection of the waterproofing on the tunnel side linings will be greatly increased if a rock-fill can be implemented on the as a backfill material for a limited width so that the gravitational drainage of the rock-fill avoids any saturation to develop at the tunnel side lining. In both cases though, the implementation of a drain pipe is mandatory. Furthermore the research has managed to deduce the applied water proofing material has malfunctioned or otherwise since it has been claimed that water proofing material has been implemented on all section of the tunnel, where there should have been less threat of leakage according to the research, the top slab of the tunnel, on actual ground it was seen to have had high leakage. I would like to thank GOD, my family and classmates for supporting me and achieve my goal. I would also like to personally thank Dr. Dereje Hailu, whose support help complete this work. Finally, I would like to give out thanks for technical support team at Geo Studio, Midas GTS and Soil Vision Office.
Appears in Collections:Railway Engineering

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