Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "Mar. 1984." "EPA/600-S2-84-021."

"A two-phase study was conducted to investigate the performance of membrane liners during construction of hazardous waste landfills and to develop a means for protecting the liners from damage. Phase I consisted of a series of full-scale field tests to determine a method of protecting flexible membranes from damage during the construction of landfills. Subgrade soils were selected to be representative of those typical of areas in which landfills are constructed. Four membranes were tested. Each was placed on top of a subgrade and covered with various thicknesses of a sand material. The test items were trafficked using three different vehicles representative of the loadings that might be applied during landfill construction. Performance of the membrane was judged by its resistance to puncture and wear. The lean clay bedding provided the best protection for the liner and was effective in preventing puncture by the subgrade. Phase II developed three laboratory tests to simulate field loadings on flexible membrane liners during construction of hazardous waste landfills. One test method used a moving pneumatic-tire loading, another used a rotating gyratory load, and the third used a .cyclic vertical plate load. Loading conditions and thickness of cover material over the membrane varied using Boussinesq equations to produce vertical stresses on the membrane similar to those encountered under field conditions. Test results showed that the moving pneumatic-tire load test would be the most useful for determining cover and bedding criteria using available site soils and candidate membranes. Also, a layer of clay soil effectively prevented puncture of the membrane by the subgrade."