Method for connecting a branch pipe to a main pipeline and underground network for distributing for distributing fluid

Method for connecting a branch pipe (4) to a main pipeline (2), in which the following operations are carried out:

• a) digging an exploration hole (8) from the ground (6) in order to open up a portion of the main pipeline (2) which has an upper edge (10) which extends at an upper level (12) which is substantially constant relative to the ground (6),
• b) using a branch connection (14) which has a support surface (16) in the form of a cylindrical portion and a shaft (18) which extends substantially perpendicularly relative to the support surface (16) and which is provided with a branch (20) which is substantially perpendicular relative to the shaft (18) and to which the branch pipe (4) is connected,
• c) positioning the support surface (16) of the branch connection (14) against the main pipeline (2),
• d) fixing the branch connection (14) to the main pipeline (2),
• e) placing the branch pipe (4) and the main pipeline (2) in communication,
• f) refilling the exploration hole (8),
• characterised in that, during step c), the shaft (18) of the branch connection (14) is positioned, with the branch (20) thereof, entirely below said upper level (12) of the main pipeline (2), or substantially at the upper level (12) of the main pipeline (2) relative to the ground (6), and, during step f), the branch pipe (4) is kept below the upper level (12) of the main pipeline (2), or substantially at the upper level (12) of the main pipeline (2) relative to the ground (6).