Drainage behavior of two-layered water-sealing polymeric systems

• Published in: Polymer testing Vol. 23; no. 1; pp. 43 - 49
• Main Authors: Farshad, M, Flüeler, P
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2004; Elsevier
• Subjects: Application fields; Applied sciences; Drainage systems; Exact sciences and technology; General equipment and techniques; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Physics; Polymer industry, paints, wood; Technology of polymers; Tunnels; Water-insulation; Drainage systems; Water-insulation; Tunnels; Drainage; Shear test; Multilayer; Compressive testing; Insulating materials; Modelling; Test equipment; Polymers; Watertightness
• ISSN: 0142-9418; 1873-2348
• DOI: 10.1016/S0142-9418(03)00060-6

In this contribution, the results of development work on testing of water isolation systems to be used in tunnels is reported. For this purpose, a testing system capable of testing rectangular samples having dimensions of 1.0×1.5 m was designed and built. This testing device was able to apply lateral compression up to 2.0 MPa and in-plane shear displacement up to 10 mm on the samples, independently. The contact surface had the same roughness as would occur during grouting of the tunnel rock. The samples were tested for the tunnel environment up to 45 °C. The experiments included short-term and long-term water-tightness as well as drainage capacity tests. The multi-layer water isolation systems consisted of water-tight membrane and surface drainage layers. The sample groups tested included surface drainage layers with knob geometry, irregularly meshed polymeric fibers, and structured mesh. It was found that the knobbed membrane systems had better drainage capacity than other types of drainage materials. To simulate the behavior of the testing system, numerical finite element analysis was performed. Furthermore, a simple theoretical model of the drainage behavior was derived. With the help of this model trends observed in the real experiments were reproduced.