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EARTHWORK TESTING Generally, earthwork excavation and filling done for proposed buildings and other structures (such as pavements and utility lines) should be tested by a geotechnical engineer. This includes observing excavations and conducting density tests in compacted fill. Excavation observations involve examining the bottom and sides of exca- vations to ascertain whether unsuitable material has been removed prior to backfilling or construction of footings. Oftentimes excavation ob- servations are correlated with information from soil test borings. Density testing involves obtaining the field density and the maximum 1 aboratory (Proctor) density of fill and then computing percent com- pact i on to determi ne whether the degree of compacti on is suitable or meets specifications. As a general guideline for percent compaction, we suggest a minimum of 95% of standard Proctor density. This applies to one to three story buildings with light to moderate structural loads (i.e. design bearing pressures of up to 3000 psf for footings), pavements, a~d utility lines. The upper 31 of fill for roadways should be compacted to at least 100% of standard Proctor density. These guidelines could be superseded by specifi c requi rements in thi s report or in project speci- fications. Percent compaction is sometimes specifi ed in re 1 at i on to mod ifi ed Proctor density. In computing percent compaction. the results based on standard Proctor density are normally 3-5% greater than results based on modifi erl Proctor density. with the actual difference depenrli ng on soil type.