Abstract
Working report submitted by The Japan Geosynthetics Technologies Association, JGTA (the working group of protection mat). Comparison work of various protection mats with light blocking effect for final waste disposal sites was conducted for two year and the problems at site was investigated by questionnaires for the members of JGTA. For the first year, each specimen with free load was exposed outdoor and the dimensional stability was evaluated. Most of the dimensional changes were proved to be less than 3%. For the second year, outdoor exposure test for the specimens with anticipated tensile force load of the actual waste site was conducted and the results showed the dimensional changes were drastically increased by the necking effect due to the longitudinal tensile load. The specimens tailored with high light stabilization formula only showed the better dimensional change of approximately 3% shrinkage in width. This value shows good correspondence with the actual field data obtained by the questionnaires. Hereafter, by means of the data from this experiment, we will establish the installation standard procedure and the construction method to prevent from the occurrences of the breakage of joint parts by strain, one of the major reasons of problems.
