The 26km (16.2 mile) long Express Rail Link (XRL) Hong Kong section is a cross boundarytransport infrastructure project, which will form part of the high speed rail servicesbetween Hong Kong and Guangzhou, China. As part of Contract 821, the Dragages-Bouygues JV constructed one of the largest tunnel intersections ever attempted inHong Kong, a 24m (78.7 ft.) span adit forming a junction with the 22m (72 ft.) span,resulting in an effective span of 32m (105 ft.).The design for temporary support is presented including development of the geologicalmodel and implementing this into 2D and 3D numerical models. The constructionsequence was fundamental in controlling stress re-distribution and interactionbetween tunnels. Instrumentation and mapping were used to verify assumptions duringconstruction. Convergence data is compared to design estimates. Lastly, recommendationsfor successful design and construction of similar tunnel intersections in rockare made.
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