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L A . M . ENGINEERING AND TESTING , INC. L ATTACHMENT A continuer) IV. Fill Placement Fill should be "clean" sand with less than five percent fines (percent of dry weight passing a U. S . No . 200 sieve) . Higher fine contents can be used but more construction control is necessary . Backfill behind walls should be very pervious , with no more than three percent fines . Where fill is to be placed on the existing ground, the surface must be prepared as indicated in Section I. The outer edges of the fill should extend sufficiently beyond the building to provide slopes with a minimum horizontal to vertical ratio of 4(H) : 1 (V) from approximately five feet outside the building perimeter to the existing grade . The fill should be placed in 12-inch thick compacted lifts with each lift compacted to at least 95 percent of the modified Proctor maximum dry density (ASTM D 1557) . The compaction should be checked with field density tests . Fill that is placed in confined areas such as utility trenches or holes should be compacted in six to eight inch thick lifts to at least 95 percent of the modified Proctor maximum dry density (ASTM D 1557) . r V. Footinp, Excavation After the footings have been excavated, a representative of A. M . Engineering and Testing, Inc . should evaluate the bottom of the footings with respect to the boring data and assess if a suitable bearing layer is present. Our representative should perform density tests to confirm that the density of the upper two feet of soil in the bottom of the footings is at least 95 percent of the modified Proctor maximum dry density (ASTM D 1557) . If the soil in the bottom of the footing was loosened during excavation or if the footings were overexcavated and then backfilled to design grade , the footing subgrade should be compacted with a vibratory plate or "jumping jack" type compactor until the required density is attained . VI. Groundwater If a high water table is encountered while the foundations are being constructed and there are difficulties with the site preparation, the project engineer or the geotechnical consultant should be advised so that appropriate construction techniques are used to overcome the problems . L VII. Monitoring and Testing We recommend that the site preparation and subsequent earthwork be monitored by an engineering technician from A. M. Engineering and Testing, Inc . The technician will observe the stripping, proof-rolling and compaction of the existing soils ; determine the suitability of fill and 60 backfill soils; observe the subgrade in the footings; and evaluate the degree of compaction attained by performing field density tests . b L Il