Linings for sewers

摘要

A sewer or tunnel lining section comprises a base sheet 14a and two side sheets 14b,14c which in use are assembled to define the lining section. Longitudinal edges of the sheets are formed with continuous interlocking tongues and grooves to enable the sheets to be connected together using adhesive to form the lining section. Side walls of each tongue and of each groove taper along substantially their full length. Preferably the length of the tongue and depth of the groove is between 2 and 4 times the width thereof at the widest point. The shapes of the tongues and grooves are selected such that each side sheet can be supported on a respective side of the base sheet solely by engagement of the tongue and groove connection with the base sheet. This arrangement facilitates the assembly of each lining section from the individual sheets.