Abstract
In pull-out tests of geomembrane in a cover soil, it is expected that failure pattern of the cover soil may be different with varying width of the geomembrane specimen and that ultimate pull-out resistance force for unit width may be different as a result. In this paper, the pull-out tests were performed varying width of the geomembrane from 1cm to 60cm under thickness of the cover soil of 10cm and 20cm. The followings are main conclusions.
(1) Under thickness of cover soil of 10cm and 20cm, the cover soil over geomembrane specimen with width of wider than 40cm moves as being accompanied by deformation of geomembrane. This results in ultimate pull-out resistance force balancing to frictional force between geomembrane and soil which was mobilized only lower surface of geomembrane.
(2) In the test where the width of geomembrane specimen with narrower than 10cm, the cover soil is stable against the deformation of geomembrane. The ultimate pull-out resistance force is larger than a value that was estimated so as to balance the frictional force mobilized both on upper and lower surface of geomembrane.
