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DWR CONSULTANTS, Inc., Geofechnical lnvesligafion <br />Proposed Saleway Gasoline Sfation, June 8, 2000 <br />6.0 CONCLUSIONS AND RECOMMENDATIONS <br />Based on the data (Section 4.0) and analysis (Section 5.0) contained herein, thi� <br />section presents our conclusions ancl recommendations. We used Ground Penetrating <br />Radar (GPR) for our investigation augmented by nearby intrusive investigations. We <br />were able to examine more of the site (about 22%) with the GPR as compared with 2 <br />boreholes that would have examined about 0.002% of the soil. The attached drawings <br />show some anomalies that should be investigated during construction (see attached <br />drawings). <br />6.1 Site Preparation <br />Rernove asphalt, islands, etc. from the area requiring construction. <br />2. The final sub-grade should be scarified to a depth of at least 4 inches, moisture <br />conditioned and compacted with at least 4 passes with a 10,000 Ib. vibratory <br />roller to a non-yielding condition. The Geotechnical Engineer, should witness ihe <br />initial process for compacting the sub-grade and approve the process or make <br />alterations as required. With proper moisture conditioning, we expect a soil <br />stiffness oi approximately 32 kips per fooi i� the moist co�dition and over 54 <br />;�ipslnch in the dry condition. <br />3. Positive drainage away (rom the pavement sub-grade should be designed and <br />c�nstructed throughout the project. <br />4. Anticipate 15-25°/a shrinkage for fine-grained soils and 5-10% shrinkage (or <br />gravel fill. <br />5. All select fill or base coarse should be compacted to at least 95% of maximum <br />dry density per ASTM D1557 or a soil stiffness of at least 50 kips/in. <br />6.2 Foundations <br />All exterior faotings should be placed at least 2 it. below the lowest adjacent <br />grade for frost proteclion. <br />2. Design spread and cont�nuous footings to impart a maximum load of 4,500 psf <br />on the native gravel layer with a minimum of 18 inches embedment below lowest <br />adjacent grade (include (loor slabs). Any gravel disturbed during the <br />cumpaction process should be re-compacted to a dense, non-yielding condition <br />with a hoe-pack or vibratory roller to a soil stifiness of at least 32 kipslnch as <br />measured with a soil stiffness gage. This will provide a soil modulus of ai least <br />Page 7 of 11 <br />