SHI Builders West Orange NJ Prelim GI SWM Report 1

soil parameters provided below apply to properly compacted granular fill and backfill placed in a well-drained, level condition and may be used for preliminary design of retaining structures. SUMMARY OF LATERAL EARTH PRESSURE PARAMETERS Internal Moist Friction Coefficient of Coefficient of Cohesion Stratum Density, Angle, Φ Active Earth Passive Earth γmoist, (pcf) (psf) Pressure (Ka) Pressure (Kp) (degrees) On-Site Natural Soils 120 -- -- -- 1000 (Fine-Grained) On-Site Natural Soils 125 30 0.33 3.0 -- (Coarse- Grained) Imported 140 32 0.31 3.25 -- Structural Fill The effect of any surcharge loads including construction equipment, traffic, proposed structures and temporary and permanent stockpiles also will need to be included in earth pressure calculations. Dynamic Earth would be pleased to assist with the calculation of lateral earth pressures based on the soil parameters presented herein during the structural design phase. Retaining walls should be designed so that the combined effect of vertical and horizontal resultant loads and overturning moment does not exceed the maximum allowable soil bearing capacity recommended in this report. Adequate drainage of water which may collect on the backfill side of the retaining walls should be incorporated into the design and/or hydrostatic pressures should be added to the pressure calculations. A system of perforated drain pipes should be used at the base of the backfill side of the wall structure to collect and remove the water and relieve hydrostatic pressure. Dynamic Earth recommends that granular soils be used to backfill the proposed subgrade and retaining walls. Clays and silts or soils with a fine fraction with a liquid limit exceeding 40 or a plastic index exceeding 20 should not be used as backfill. Based on the subsurface condition encountered and laboratory test results, the

ils with a fine fraction with a liquid limit exceeding 40 or a plastic index exceeding 20 should not be used as backfill. Based on the subsurface condition encountered and laboratory test results, the portions of the on-site soils are expected to be suitable for reuse as structural fill behind proposed retaining walls provided they can be properly prepared and compacted during construction. However, portions of the on-site soils included an increased percentage of fine-grained material (silt and clay). As such, the final retaining wall design will need to be reviewed to confirm reuse of the on-site soils as structural fill. Acceptable backfill should be placed in maximum nine-inch loose lifts and compacted to 95 percent of the maximum dry density, within two percent of the optimum moisture content, as determined SHI Builders 15 4266-99-001E