DEVELOPMENT OF SECONDARY LINING FREE QUAD SECTIONED REINFORCED CONCRETE SEGMENT

Abstract

Recently, attention is drawn on elimination of secondary lining as one of the cost reducing theme for shield tunneling works. The authors have developed a segment system which is adaptable in eliminating secondary lining for small sized and mid sized shield tunnels. This segment system is based on segment pieces built from four reinforced concrete sections. By adopting a simplified joint system and optimization of joint locations, cost down as well as smoothness of internal surface and improvement in durability have been achieved. In addition, a mockup loading test was carried out to verify the soundness of the design approach of segments.