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Septum 16 shielding increase. 19 November 2013 . Requested : - Additionnal depth of earth of between 1.2m and 3.4m over Septum 16 area Constraints : Existing structures not strong enough to take the additional load
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Septum 16 shieldingincrease 19 November 2013
Requested: • - Additionnaldepth of earth of between 1.2m and 3.4m over Septum 16 area • Constraints: • Existing structures not strong enough to take the additional load • Area with a very complex geometry (PS, Linac 2&3, Leir, TT2, . .) • Works must have no influence or impact on the existing structures
-A new load-bearing structure taking the weight of the additionalearth and redirectingitinto the bedrockunderneath. -The structure consists of a 1.10 m thick reinforced concrete slab and the additional depth of backfill will be placed directly on the slab. -The slab rests on drilled piles and on intermittent supports on the tunnel roof Proposed solution :
Slabdeformation: 56 mm 51 mm
To protect the existing structures, the transfer slab must guarantee that even after long-term deformation the load-bearing relief structure does not under any circumstances come to rest on the existing structures. • To this end, it was foreseen to use a biodegradable honeycomb cardboard formwork that could be bedissolved with water. This procedure guaranteed that, once water had been injected to dissolve the cardboard, a void of 10 cm remained after concreting, which was more than enough to allow for the long-term deformation of the slab
Status– 19 November 2013 • Adjudication of the works on 19 June 2013 • June-July 2013 - Preparatoryworks • July 2013 – Earthworks • September2013 - Pilingworks • 2 October 2013 – Start of concretingworks – Stage 1a • 8 October 2013 – Works stoppage – The biodegradableformworkgetswetbeforeconcreting ! • 8-16 October 2013 – Removal of the formwork&reinforcement of stages 1b and 2a • 18 October 2013 - a new method is developed and tested: sand instead of biodegradable formwork, to be pumped out prior to backfilling • Now – Stages 1b and 2a concreted using the new method
Somepictures of the works: Pilingworks – September 2013 Earthworks - July 2013
New schedule End of the works: 15/03/2013 (to beconfirmeddepending on the speed in pumping the sand)