AIR PERMEABLE IMPERVIOUS SHEET AND IMPERVIOUS METHOD USING SAME

摘要

PURPOSE:To obtain a impervious sheet provided with both air permeability and water imperviousness, and a method using the above sheet. CONSTITUTION:A large number of air permeable through holes are formed by needling treatment on a impervious sheet material made of a soft polymer material. It is preferable to apply an air permeable mat material 2 made of a foaming polymer material on one or both surfaces of a sheet material 1, and it is preferable that at least a part of the air permeable impervious sheet is extended to the part of the air permeable mat material 2. It is preferable to adopt a method of burying the air permeable impervious sheet with a protection layer of sand and gravel.