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� 4.3 Mass Grading Recommendations Excavation We understand that the existing house and detached garage will be demolished to make way for the new home. We recommend all remnants of the structures including footings, foundation walls, slabs and underground utilities be removed from within the proposed building and oversize areas. We further recommend that all pavements, vegetation, topsoil, fill, organic soil and soft clays be removed from the proposed building and oversize azeas. Table 2 below summarizes the anticipatecl excavation depths at the boring locations.Excavation depths may vary and could be deeper. Table 2. Antici ated Excavation De ths Bo�g Surface Anticipated Anticipated Anticipated Number �evation Excavation Excavation Groundwater feet De th feet* Elevation feet * Elevation feet * S&1 932.3 12 9201/2 929 SB-2 931.4 7 9241/z 929 *Eaccavation depths and elevation were rounded to the nearest�/z foot. We recommend fill required to replace the soil removed during soil corrections consist of granular soil (sand) meeting the ASTM Classifications SP. We recommend soil with less than 5 percent passing the number 200 sieve and at least 50 percent retained on the number 40 sieve. Organic soils such as topsoil, organic silt or soils that are black in color are not suitable for use or reuse as structural fill. Oversizing If the excavation extends below the proposed footing elevation, the excavation requires oversizing. We recommend the perimeber of the excavation be extended a foot outside the proposed footprint for every foot below footing grade (1H:1V oversizing). The purpose of the oversizing is to provide lateral support of the foundation. Excavations for soil corrections are anticipated to extend to depths ranging from about 7 to 12 feet below the ground surface. At excavation side slopes of 1H:1V the excavation will extend 7 to 12 feet laterally beyond the perimeter of the excavation. Excavations could extend onto adjacent properties posing a significant risk of undermining structures on those properties. If site constraints will limit the excavations,temporary shoring will be required. Dewatering Groundwater likely matches the water level of Lake Minnetonka which is at a depth of 3 to 4 feet below the ground surface. T'he deeper soil corrections will extend below groundwater levels. In addition, utility installations will likely extend to depths ranging from about 7 to 10 feet below the ground surface which will extend below the ground water level. We anticipate that dewatering will be required. We recommend the groundwater level be temporarily lowered to a minimum of 2 feet below the lowest anticipated excavation elevation to allow for construction. In sandy soils we do not recommend attempting to dewater from within the excavation. Upward seepage will loosen and disturb the excavation, resulting in a "quick condition." Rather, we recommend groundwater be drawn down below the anticipated excavation bottom. 5