FORMATION OF CAVITIES IN THE BED OF A SHEET OF WATER

摘要

1478949 Forming subaqueous cavities C G DORIS (COMPAGNIE GENERALE POUR LES DEVELOPPEMENTS OPERATIONNELS DES RICHESSES SOUS-MARINES) and SOC FRANCAISE DE STOCKAGE GEOLOGIQUE GEOSTOCK 26 March 1975 [4 April 1974] 12573/75 Headings E1F and E1H A method of forming a gallery or storage chamber in a subaqueous bed comprises constructing a structure, Fig. 1, having two hollow shafts 1 and 2, floating it to a site and setting it on a sea-bed 11, excavating a bore 22 or 23, in extension of the hollow shaft, easing the bore to render it water tight, and using the bore as access for the excavation of galleries 47. In Fig. 1 the structure comprises platform 16, and 17 for personnel and equipment, and a ballast member 7, which can also be used for the storage of hydrocarbons. It also comprises stability spades 20, 21, and a retaining wall 8. In this structure of Fig. 1 hollow shaft 1 is intended to be used for access to the excavation of. personnel and equipment and shaft 2 is for removal of spoil, which can be subsequently dumped around the structure base. The bores 22, 23 can be formed by drilling or explosives, and the casing sections (37), Fig. 5 not shown, placed in position by pile-driving. The annular cavities are filled with concrete, with the section adjacent the bed 11 having a polymer added to render it flexible. Openings 42, 43 are formed in the casing walls, with air-locks 32a, 33a prior to excavation of the galleries. In Fig. 7, not shown, the galleries take the form of intersecting passages (47)- (52). In Fig. 8 a single chamber 54 is formed which can be connected to a tanker (61) via a buoy (64) and intermediate tank (7).