Tunnel Monitoring Surveys

STRUCTURAL FRAMES, BRIDGES & TUNNELS Williamson Technical Services have been monitoring structures, bridges and tunnels throughout their year history. During the 1980's and 90's they worked with the Transport and Road Research Laboratories providing a service to monitor the 3 dimensional deformations during the load testing, to destruction, of 10 no. masonry arch bridges to sub-millimeter tolerances using surveying techniques. The results of the monitoring being presented both graphically and digitally. Similar techniques, combined with other geotechnical monitoring instruments, have been used to monitor convergence in caverns, brick lined and hard rock tunnels. The advantage of using these techniques over traditional invar wire or tape extensometers is that the measurement of movements can be given an absolute direction instead being restricted to a relative one. Work was recently completed on monitoring deflections at 30 positions on an access structure which was loaded in increments over a period of 4 weeks. Use of high precision electronic instruments with an automatic target seeking facility enables such projects to be undertaken with the minimum level of human supervision.

For more information on Tunnel Monitoring Surveys talk to Williamson Technical Services Ltd