SHI Builders West Orange NJ Prelim GI SWM Report 1

may be proposed due to existing site topography and/or along the property lines (if necessary). Dynamic Earth presents the following preliminary design recommendations for use when designing proposed retaining walls requiring lateral earth pressure estimates. Soil Parameters and Design Considerations: Proposed retaining walls that are free to rotate generally can be designed to resist active earth pressures. Restrained walls and retaining wall corners need to be designed to resist at-rest earth pressures. Backfill soils adjacent to these structures should consist of freely draining materials composed primarily of sand and gravel. The SHI Builders 14 4266-99-001E

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

by ASTM D 1557 (Modified Proctor). A maximum density of 140 pounds per cubic foot should not be exceeded in order to avoid creating excessive lateral pressure on the walls during compaction operations. Dynamic Earth recommends that backfill directly behind the walls be compacted with light, hand- held compactors. Heavy compactors and grading equipment should not be allowed to operate within a zone measured at a 45-degree angle from the base of the walls during backfilling to avoid developing excessive temporary or long-term lateral soil pressures. Resistance to sliding should be provided by friction resistance at the base of the retaining structure foundation, as detailed herein. 5.8 Seasonal High Groundwater and Soil Permeability Indicators of seasonal high groundwater (i.e. based on soil mottling) were encountered within the soil profile pit excavations at depths ranging between approximately 1.4 feet and 5.0 feet below the ground surface; corresponding to elevations ranging between approximately 621.3 feet and 612.4 feet. Groundwater was encountered at depths ranging between approximately two feet and 9.6 feet; corresponding to elevations ranging between 621.3 feet and 562.1 feet during our investigation. A summary of the seasonal high groundwater levels and permeability test results is presented in the following table: Estimated Seasonal High Groundwater and Permeability Summary Surface Mottling1 Groundwater Permeability Test Results Location Elevation Depth Depth Depth Permeability (in/hr) Elevation Elevation (ft) (ft) (ft) (in) A B SPP-1 623.3 2.0 621.3 2.0 621.3 24 <0.2 <0.2 24 <0.2 <0.2 SPP-2 616.2 1.4 614.8 2.0 614.2 54 Not Tested 20 <0.2 <0.2 SPP-3 615.0 Not Encountered 9.6 605.4

20 <0.2 <0.2 SPP-3 615.0 Not Encountered 9.6 605.4 48 Not Tested 26 Not Tested SPP-4 621.6 5.0 616.6 5.6 616.0 36 <0.2 <0.2 SPP-5 616.9 4.5 612.4 24 <0.2 <0.2 Not Encountered SPP-6 611.9 Not Encountered 24 <0.2 <0.2 24 Not Tested SPP-7 620.4 2.6 617.8 3.7 616.7 36 <0.2 <0.2 28 SPP-8 571.1 Not Encountered 9.0 562.1 Not Tested 34 SHI Builders 16 4266-99-001E

Estimated Seasonal High Groundwater and Permeability Summary Surface Mottling1 Groundwater Permeability Test Results Location Elevation Depth Depth Depth Permeability (in/hr) Elevation Elevation (ft) (ft) (ft) (in) A B SPP-9 535.2 24 Not Tested Not Encountered Not Encountered SPP-10 525.7 24 Not Tested 1 Where mottling was not encountered, the depth to seasonal high groundwater can be approximated from the soil survey and/or with direct groundwater readings during the wet season. 5.9 Temporary Excavation The soils encountered during the investigation are consistent with Type C Soil Conditions as defined by 29 CFR Part 1926 (OSHA) which require a maximum unbraced excavation angle of 1.5:1 (horizontal: vertical). Actual conditions encountered during construction should be evaluated by a competent person (as defined by OSHA) to ensure that safe excavation methods and/or shoring and bracing requirements are implemented. 5.10 Preliminary Seismic and Liquefaction Considerations The soils are most consistent with a Site Class D defined by the International Building Code. Based on the seismic zone and soil profile, liquefaction considerations are preliminarily not expected to have a substantial impact on design. 5.11 Supplemental Evaluation and Investigation Final Design/Supplemental Investigation: Since these preliminary geotechnical investigation activities have been completed during the initial design phase, many critical assumptions or preliminarily details regarding assumed structural loads, existing and proposed elevations, etc. affect the geotechnical analysis. The preliminary considerations presented herein should be considered to help develop the optimum site design and grading, and Dynamic Earth should remain involved during final design. A supplemental investigation including the advancement of additional soil borings, test pits, and

lop the optimum site design and grading, and Dynamic Earth should remain involved during final design. A supplemental investigation including the advancement of additional soil borings, test pits, and laboratory testing should be performed within building areas as part of the final geotechnical investigation for the site. Dynamic recommends performing supplemental investigation throughout the proposed site once the design layout and grading becomes finalized in order to confirm the recommendations herein and/or provide additional recommendations, if required. Construction Monitoring and Testing: The recommendations presented herein are contingent on the owner retaining Dynamic Earth to perform inspection, testing and consultation during construction as described in previous sections of this report. Construction phase evaluation by means of proofroll inspections, soil probes, and/or subgrade inspections will be needed to confirm adequate support for the proposed structures. Monitoring and testing should also be performed to verify that suitable materials are used for controlled fill, and that they are properly SHI Builders 17 4266-99-001E

placed and compacted over suitable subgrade soils. Testing of fill placement will also be critical to limiting differential settlement. SHI Builders 18 4266-99-001E

6.0 GENERAL COMMENTS AND LIMITATIONS Supplemental recommendations will be required upon finalization of conceptual site plans or if significant changes are made in the characteristics or location of the proposed structures. Dynamic Earth should be included as a consultant to the design team and should be provided final plans for review to confirm these criteria apply or to modify recommendations as necessary. The recommendations presented herein should be utilized by a qualified engineer in preparing preliminary design concepts and site grading. The engineer should consider these recommendations as minimum physical standards that may be superseded by local and regional building codes and structural considerations. These recommendations are prepared for the use of the client for the specific project detailed and should not be used by any third party. These recommendations are relevant to the preliminary design phase and should not be substituted for construction specifications. The possibility exists that conditions between test locations may differ from those at specific test pit locations, and conditions may not be as anticipated by the designers or contractors. In addition, the construction process may itself alter soil conditions. Therefore, Dynamic Earth Geotechnical Engineers or their representatives should observe and document the final construction procedures used and the conditions encountered, as well as conduct testing and inspection to ensure the design criteria are met or recommendations to address deviations are implemented. Dynamic Earth assumes that a qualified contractor will be employed to perform the construction work, and that the contractor will be required to exercise care to ensure all excavations are performed in accordance with applicable regulations and good practice. Particular attention should be paid to avoiding damaging or undermining adjacent properties and maintaining slope stability. The exploration and analysis of the foundation conditions reported herein are presented to form a reasonable basis for preliminary site evaluation. The recommendations submitted for the proposed construction are based on the available soil information and the preliminary design details furnished or assumed. Deviations from the noted subsurface conditions encountered during construction should be brought to the attention of the

able soil information and the preliminary design details furnished or assumed. Deviations from the noted subsurface conditions encountered during construction should be brought to the attention of the geotechnical engineer. The geotechnical engineer warrants that the findings, recommendations, specifications, or professional advice contained herein have been promulgated after being prepared in accordance with generally accepted professional engineering practice in the fields of foundation engineering, soil mechanics, and engineering geology. No other warranties are implied or expressed. SHI Builders 19 4266-99-001E