TPT September 2011

T echnology U pdate

Jacking pit in operation

ORBITAL WELDING sOLuTIONs ExtrEmEly rElIABlE tEchnology

to conduct the job with seven intermediate stations, approximately every 150m (three on the short stretch, four on the long), each of which had a drive force equalling 1,078 tons. These were usually put to service for initiating the drives. Three manholes were installed 200 to 250m apart from each other, and two special chambers, one hosting a flushing and the other equipped with a vacuum system for deodorisation, were included along the collector. Preparing for their installation, the contractor neatly cut the soil and cast concrete to establish walls around a part of the pipe route without prior excavation works, and before the boring machine had passed the section. After the concrete had cured, the bore head drilled through the established walls, and the soil around the pipe in the concrete chamber was excavated, either completely as for the flushing and deodorising chambers or down to the pipe in order to install the tangential manholes. The latter were erected by cutting and laminating a Hobas DN 1000 GRP pipe vertically onto the DN 1800 jacking pipe. The construction of the complete project, including the installation of supplementary equipment and the pumping stations, was finalised within 13.5 months – a short time, considering the scope of the job and the difficult geological conditions, which included inhomogeneous, abrasive soils soaked with ground water. Hobas Engineering GmbH – Austria Fax: +43 463 482121

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Email: info@hobas.com Website: www.hobas.com Hobas France SAS – France Fax: +33 1 3435 0858 Email: hobas.france@hobas.com Website: www.hobas.fr

2, rue Paul Beaupère (F) 44300 Nantes Tel. +33 (0) 2 40 68 11 00 - Fax +33 (0) 2 40 68 11 88 info@polysoude.com - www.polysoude.com

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S eptember 2011

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