Shield segment elastic rubber gasket is the main material used for assembled tunnel segments sealing, which is a composite of single porous EPDM rubber or porous EPDM rubber and the expandable rubber. The surface contact stress of the material is almost unchanged even if the seam opening volume changed within the specific range of the seam opening volume.
If the seam is fully closed, it also won't generate excessive stress from segment ends, it can keep surface contact stress sufficiently.
Porous rubber waterstop can reduce compressive stress, increase the segment seam opening volume, and can be not easy to be stress relaxation and permanent deformation by long-term compression.
It also can become expandable rubber composite gasket when made up with expandable rubber, if EPDM gasket leaks, slow expansion-type expandable rubber strip will begin to expand slowly to waterproof, so that play asecond layers of waterproof role.