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Field tests (double ring infiltrometer) can be performed within the proposed infiltration basin <br /> area to verify infiltration rates of the in-situ soils. We would be pleased to provide these <br /> services if required or requested. <br /> 5.0 CONSTRUCTION CONSIDERATIONS <br /> 5.1 Excavation <br /> The soils encountered in the borings consisted of predominantly of sandy soils consisting of <br /> poorly graded sand, poorly graded sand with silt and silty sand corresponding to the ASTM <br /> classifications of SP, SP-SM and SM. These soils will generally be Type C soils under <br /> Department of Labor Occupational Safety and Health Administration(OSHA) guidelines. <br /> The borings also encountered clayey sand and silty clay that mostly had a soft consistency. <br /> For that reason, the clayey sand and silty clay will also generally be Type C soils under <br /> OASHA guidelines. <br /> Temporary excavations in Type C soils should be constructed at a minimum of 1 1/2 foot <br /> horizontal to every 1-foot vertical within excavations. Slopes constructed in this manner may <br /> still exhibit surface sloughing. If site constraints do not allow the construction of slopes with <br /> these dimensions,then temporary shoring may be required. <br /> 5.2 Observations <br /> A geotechnical engineer or a qualified engineering technician should observe the excavation <br /> subgrade to evaluate if the subgrade soils are similar to those encountered in the borings and <br /> adequate to support the proposed construction. <br /> 5.3 Backfill and Fills <br /> We recommend moisture conditioning all soils that will be used as fill or backfill in accordance <br /> with Section 4.3 above. We recommend that fill and backfill be placed in lifts not exceeding 4 <br /> to 12 inches,depending on the size of the compactor and materials used. <br /> 5.4 Testing <br /> We recommend density tests of backfill and fills placed for the proposed building foundations. <br /> Samples of the proposed materials should be submitted to our laboratory prior to placement <br /> for evaluation of their suitability and to determine their optimum moisture content and <br /> maximum dry density (Standard Proctor). <br /> 5.5 Winter Construction <br /> If site grading and construction is anticipated to proceed during cold weather, all snow and <br /> ice should be removed from cut and fill areas prior to additional grading and placement of <br /> fill. No fill should be placed on frozen soil and no frozen soil should be used as fill or backfill. <br /> 13 <br />