soil exploration/geoptechinical investigation-2004

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although other provisions and restrictions may apply. The design maintenancee of temporary slopes is the responsibility of the contractor. TABLE C COMPACTION REQUIREMENTS FOR STRUCTURAL FILL AND BACKFILL _ Relative Density Standard Proctor Standard Proctor ASTM D4253 Construction Applications ASTM D698 ASTM D698 ASTM D4254 -- Cohesive soil Cohesionless soil Cohesionless soil (lean clay) (sand and gravel) (sand.and gravel) N (%) N • Foundations.for buildings and other structures 95 98 75 • Roadway sub-grades • Critical backfill areas — • Minor surface subsidence is possible and allowable _ • Backfill adjacent to structures not supporting other structures 90 93 45 • Backfill will not support other — structures and buildings • Backfill for pipe or utility trenches • Backfill in non-critical areas where moderate surface 85 88 20 subsidence is possible and allowable Note (A) Use relative density technique (ASTM D4253 and 04254) where Standard Proctor (ASTM D 698) curve does not have a clear peak at maximum dry soil density and optimum water content. OVER-EXCAVATION AND STRUCTURAL BACKFILL Where soil beneath planned bearing grades of foundations and structures, floor slabs, pavement and structural fill either appears or is likely to be unsuitable and unreliable to support these features, and over-excavation and structural backfill procedure may be necessary. We recommend that a Professional Engineer from our company observe, test and review this soil condition, to determine if the soil must be removed and replaced with structural backfill. We _ recommend that the Engineer determine depth and lateral extent of over-excavation. The over- excavation must extend deep enough to completely remove unsuitable and unreliable soil beneath bearing, grades of these features. Unsuitable and unreliable soil is defined in the second paragraph in the EXCAVATON AND EARTHWORK section of this report. Allied Project 04049 12 July27, 2004