Designing waterproofing
for shield tunnel segments with water expansive materials
Masahiro OHTSUKA1, Toru KOBAYASHI2, Atsushi
KOIZUMI3,
1. Tokyo Electric Power Company; 2. Nippon Civic Consulting Engineers Co.,
Ltd; 3. Waseda University
Proceedings of the JSCE, No. 651/VI-47, pp.61-79. June 2000.
Key words: Shield tunnel, segment lining, waterproofing design, seal, performance-based
design methods, waterproofing material test
Background
Shield tunneling is being increasingly used for urban tunnel construction as
it safeguards overlying structures. Tunneling depths of urban shield tunnels
have recently been increasing, and better performance of the waterproofing
materials and capability to withstand higher pressures is required. Waterproofing
of such shield tunnels is critical to maintain both the environment of the
existing overlying facilities and the shield tunnel itself. However, waterproofing
design of shield tunnels is based on experience and past results, and there
is no established waterproofing design method.
Research Summary
We carried out many tests
of waterproofing materials commonly used for shield tunnels.
Hydrophilic materials that expand
in contact with water were tested
for their sealing performance in situations that actually arise in design,
such as "no seal groove provided", "seal groove provided",
or "uneven alignment of segments". From the results of the tests,
waterproofing mechanisms were better understood. A flowchart for quantitative
design of waterproofing materials was developed and a detailed waterproofing
design method proposed. Furthermore, an investigation was carried out into
the material coefficient ƒÁs taking the variation in properties of the waterproofing
material into account, and a design method complying with performance-based
design methods was introduced. As a result, quantitative design for waterproofing
materials is now possible.
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