1. Final tunnel liner at the Mill Creek 3 project.
- Author
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Schafer M., Janosko S., Kritzer M., Lukajic B., Pintabona R., Switalski R., Schafer M., Janosko S., Kritzer M., Lukajic B., Pintabona R., and Switalski R.
- Abstract
The construction is described of the Mill Creek sewer tunnel in Ohio, USA. A full-face fully shielded tunnel boring machine was used to excavate about 4 500 m of tunnel and to facilitate the installation of initial supports. The final lining consists of 305 mm thick cast-in-place reinforced concrete and integral low-flow channel. The project involved the construction of seven shafts. The presence of overbreak in the tunnel crown required measures to support the form and to counteract the effects of buoyancy during concrete emplacement. Two steel Z beams were installed in the tunnel crown. Load-cell monitoring of the form buoyancy was carried out and the results showed that areas of the tunnel with more extensive overbreak required additional support. The invert of the tunnel form was fitted to allow rock bolts to be installed and resin bolts were employed in areas requiring extra support. The liner design and construction sequence are described., The construction is described of the Mill Creek sewer tunnel in Ohio, USA. A full-face fully shielded tunnel boring machine was used to excavate about 4 500 m of tunnel and to facilitate the installation of initial supports. The final lining consists of 305 mm thick cast-in-place reinforced concrete and integral low-flow channel. The project involved the construction of seven shafts. The presence of overbreak in the tunnel crown required measures to support the form and to counteract the effects of buoyancy during concrete emplacement. Two steel Z beams were installed in the tunnel crown. Load-cell monitoring of the form buoyancy was carried out and the results showed that areas of the tunnel with more extensive overbreak required additional support. The invert of the tunnel form was fitted to allow rock bolts to be installed and resin bolts were employed in areas requiring extra support. The liner design and construction sequence are described.