L.A. Lopez Hernandez Route Goward and Septum 16 shielding increase LS1 Committee - 21 st - 20...
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Transcript of L.A. Lopez Hernandez Route Goward and Septum 16 shielding increase LS1 Committee - 21 st - 20...
L.A. Lopez Hernandez
Route Goward and Septum 16 shielding increase
LS1 Committee - 21st - 20 September 2013
• The shieIding increase of the PS over Route Goward passage and over Straight Section 16 was proposed by RP, recommended by the PSRWG, presented at the IEFC and endorsed by the management
• The cost of the intervention has been included in the PS‐LIU budget
RP presentation from 59th IEFC (S. Damjanovic)
The extra-concrete shielding requiredfollowing HSE recommendationswas ~ + 180 cms.
Route Goward
Proposed solution: Concrete slab 2 m thick
Piling wall protecting the tunnel from the load of the road
Works carried out:
-Earthworks -Temporary road to give limited access to the center of the ring during the construction works -Piles -Concrete slab 2 m thick -New road ~ 100 m long, including retaining walls, backfilling, modification of the existing networks, etc
Schedule:
Currently: -Road open -Works finished on schedule
Temporary road
Retaining wallPiling works
Some pictures of the works:
Slab reinforcement
Formwork for the slab
Biocofra
Concreting
Road works
Backfilling
RP presentation from 61st IEFC (S. Damjanovic)
The extra-concrete shielding requiredfollowing HSE recommendationshas been converted in earth shieldingNew max ground level: 442.6 m (means between +1.2 and +3.4 m over the existing level)
Straight Section 16
Requested: - Additionnal depth of earth of between 1.2m and 3.4m depending of the 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
Feasibility studies:
Proposed solution : -A new load-bearing structure taking the weight of the additional earth and redirecting it into the bedrock underneath.
-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, or secant piles in areas subject to particularly heavy loads
-In the places where the existing tunnels are made of large masses of concrete, the slab rests on intermittent supports on the tunnel roof
Bird’s eye view of the new slab:
- 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, the slab will rest on a biodegradable honeycomb cardboard formwork that can be dissolved with water. This procedure guarantees that, once water has been injected to dissolve the cardboard, a void of 10 cm remains after concreting, which is more than enough to allow for the long-term deformation of the slab
Biocofra:
Slab deformation:
51 mm
56 mm
Schedule
Currently: -Piles finished-Concreting works starting
Worksite installations:
Parking route Gowardshared with CV
Concrete batching plant
Temporary spoil dump
Access to building 561 (RP)
«Passage pieton» closed
L.A. Lopez Hernandez 19
Monitoring of the existing structures -Photographic survey of the structures
-Camera inspection of the drains ~ 300m
-Vibration measurements during piling works
LS1 Committee - 21st
- Maximum particle velocity for historical buildings < 2 mm / s
- Max value recorded: 1.19 mm/s on sensor 2
- 3D modeling of the (shielding + existing structures +ground) for prediction of displacements
Some pictures of the works:
Thank you for your attention