a segment lining system subject to internal water pressure
Masayuki SAITOH and colleagues
Nippon Civic Consulting Engineers Co., Ltd.
5th International Conference on Pipelines, October 1997
Key words: shield tunnel, segment lining, segment joint, internal water pressure,
underground reservoir, FEM analysis, beam-spring model
Where vacant land is not available for conventional above-ground flood control
reservoirs, as is commonly the case in Japanese cities, large diameter shield
tunnels can be constructed to serve as underground regulating reservoirs. Such
tunnels are subject to unusual loading conditions; most of the time they are
empty, so external loads due to soil and groundwater pressure are dominant.
But occasionally, when there is a flood, water pressure loading acts from within
the tunnel, and tensile forces are generated on the RC segment linings and
We proposed a segment lining structure with a new joint structure for shield
tunnels subject to internal water pressure. A series of load tests on full
scale model segment pieces was carried out, and the performance required for
the linings of internal water pressure shield tunnels was confirmed. The joint
structure of the newly proposed lining structure adopted a staggered joint.
The locking mechanism of the new staggered jointing structure was verified
by numerical analysis using the finite element method (FEM). Load tests were
carried out with jacking loads on full scale test pieces. Internal water pressure
tests were carried out on a 5 m external diameter segment ring model, and the
performance of the new segments was verified. It was also demonstrated that
the behavior of the segment ring model could be simulated with a beam-spring
analysis model, so a method of designing shield tunnels using the new segment
lining structure was proposed.