| 摘要 |
<p>The disclosure relates to an arcuate concrete tunnel lining segment having an arcuate PVC plastics shell (11) extending over its inner surface. The shell (11) has outwardly extending side walls (12) overlying the sides of the segment. The outer circumferential edges of the side walls are formed with inwardly directed T-section ribs (13) formed integrally with the side walls and bonded into the concrete segment and the outer surface of the shell is formed with a similar multiplicity of spaced T- section ribs (14) likewise bonded into the concrete of the segment. The shell protects the concrete segment against attack from corrosive substances which would otherwise degrade the concrete. <IMAGE></p> |
