6101 23RD DR W NORPRO Geotech Report 2025-07-29

June 3, 2011 Project No.'T-6578 Accordingly, for temporary excavations of less than 20 feet in depth, the side slopes in Type C soils should be laid back at a slope inclination of 1.5:1 or flatter from the toe to the crest of the slope. Similarly, excavations in Type A soils can be laid back at a slope inclination of 0.75:1 or flatter. For temporary excavation slopes less than 8 feet in height in Type A soils, the lower 3 %z feet can be cut to a vertical condition,with a 0.75:1 slope graded above. If there is insufficient room to complete the excavations in this manner, or if excavations greater than 20 feet deep are planned, you may need to use temporary shoring to support the excavations. All exposed slope faces should be covered with a durable reinforced plastic membrane during construction to prevent slope raveling and rutting during periods of precipitation. 1 This information is provided solely for the benefit of the owner and other design consultants, and should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety. It is understood that job site safety is the sole responsibility of the project contractor. I Slopes All permanent cut and fill slopes should be graded with a finished inclination of no greater than 2:1. Upon completion of grading,the slope face should be appropriately vegetated or provided with other physical means to guard against erosion. Final grades at the top of the slope must promote surface drainage away from the slope crest. Water must not be allowed to flow uncontrolled over the slope face. If surface runoff must be directed towards the slope, the runoff should be controlled at the top of the slope, piped in a closed conduit installed on the slope face, and taken to an appropriate point of discharge beyond the toe. I All fill placed for embankment construction should meet the structural fill requirements in the Site Preparation and Grading Section. In addition, if the new fills will be placed over existing slopes of 20 percent or greater, the structural fill should be keyed and benched into competent native slope soils. Figure 3 presents a typical slope key and bench configuration. 5.4 Foundations In general, native soil conditions throughout the site wiII be suitable for support of conventional spread footing foundations. Allowable design bearing capacities will be dependent on design elevations with higher bearing capacities typically available in the lower dense to very dense granular soils. For foundations bearing on the upper weathered till soils or structural fill placed above competent native soils, we recommend dimensioning them for a net allowable bearing capacity of 3,000 pounds per square foot (psi). For foundations supported on unweathered glacial soils at a depth of four feet below existing surface grades, a net allowable bearing capacity of 6,000 psf can be used. A one-third increase in these bearing values can be used when considering short-term transitory loading. Estimated total foundation settlement with expected structural loading and these bearing pressures applied fall in the range of one-half to one-inch. I Page No. 8