Plastic pipes have long life because of their resistance to corrosion and erosion. Consequently, they are attractive for use under long-term landfills and in aggressive environments such as sanitary landfills. But sanitary landfills are usually high landfills. Tests at Utah State University investigated the performance of plastic pipes under high landfills. It was found that a plastic pipe can perform under enormous soil loads -- hundreds of feet -- if an envelope of carefully selected soil is carefully placed about the pipe. The creep of plastic materials allows the pipe to relax and so to conform with the soil in a mutually supportive pipe-soil interaction.