Geotechnical and geophysical campaign of Capbreton Canyon in the Gulf of Biscay for alternative cable crossing

Cantidad o extensión

A) Geophysical survey along a corridor bypassing the Capbreton Canyon head very close to the coastline between the 10 and 5 m w.d. contour. SSS, MBES and deep towed or parametric SBP are required, with a line plan to cover the entire corridor 200 m width and at least with 4 SBP runs on selected routes according MBES and SSS results. The reference line (centre line) for this corridor is reported in the Technical Survey Requirement (TSR) and is long at least 15 Km. Data processing on board or on site, for the route selection where to perform the SBP and to select the soil samplings.B) Sub-bottom profiles on 4 specific routes crossing the Capbreton Offshore Crossing area as described in the TSR for a total length of approx. 13 Km.C) Geotechnical survey performing 24 CPT, as basic quantity, shared on the 4 routes of Capbreton Offshore Crossing area according to the RPL's in TSR. Nominal CPT penetration shall be 6 m at any w.d. in this area. Max w.d. in this CBC Offshore area is 300 m. CPT rig to be controlled remotely for the verticality on slopes up to 20°.D) Geotechnical survey performing 30 CPT, as basic quantity, in the corridor investigated as per item A) at locations to select according to the SBP results achieved and presented on board / on site. Required penetration at w.d. < 30 m shall be >6 m unless refusal.E) Geotechnical survey performing 40 cores, as basic quantity, by gravity corer or vibrocorer, according to the results achieved by CPT, to be shared along the coastal option corridor and in Capbreton Offshore Crossing area, 10 vibrocores at least are envisaged at w.d. < 30 m. Vibrocorer rig to be controlled remotely for the verticality on slopes up to 20°.Other basic requirements: DP vessel to operate in all areas or DP vessel for deep water + other suitable vessel/ platforms for very shallow water if DP vessel is not available for all the job.Permits and authorization for working will be on Contractor charge and responsibility.