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Table 6 indicates the recommended compaction levels. Table 6: Recommended Level of Compaction for Backfill and Fill Area Percent of Standard Proctor Maximum Dry Density Pavement: Within 3 feet of top of subgrade 100 Pavement: Greater than 3 feet below top of subgrade 95 Utility Trench 95 Landscaping (non-structural) 90 4.6 Construction Considerations Good surface drainage should be maintained throughout the work so that the site is not vulnerable to ponding during or after a rainfall. If water enters excavations, it should be promptly removed prior to further construction activities. Under no circumstances should fill be placed into standing water. Soil corrections at this site for pavement subgrades may not be continuous in all areas. We recommend tapering the fills back to native soils at a ten to one (10:1) slope. 4.7 Construction Safety All excavations must comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P "Excavations and Trenches". This document states that excavation safety is the responsibility of the contractor. Reference to this OSHA requirement should be included in the job specifications. The responsibility to provide safe working conditions on this site, for earthwork, building construction, or any associated operations is solely that of the contractor. This responsibility is not borne in any manner by WSB. 4.8 Cold Weather Construction It is our understanding that construction is unlikely to occur during the winter months. However, if the construction does continue into the winter months we recommend the following guidelines. Only unfrozen fill should be used. Placement of fill must not be permitted on frozen soil. 4.9 Field Observation and Testing The soil conditions illustrated on the Logs of Test Borings in Appendix A are indicative of the conditions only at the boring locations. WSB also recommends a representative number of field density tests be taken in all engineered fill and backfill placed to aid in judging its suitability. Fill placement and compaction should be monitored and tested to determine that the resulting fill and backfill conforms to specified density, strength or compressibility requirements. We recommend at least one compaction test for every 300 linear feet of utility trench and roadway area, at vertical intervals not exceeding 2 feet. Prior to use, any proposed fill and backfill material should be submitted to the WSB laboratory for testing to verify compliance with recommendations and project specifications. Dynamic Cone Penetrometer (DCP) tests can be completed in the aggregate base in lieu of density testing. We recommend following MnDOT Specification 2211-3. WSB would be pleased to provide the necessary field observation, monitoring and testing services during construction. Geotechnical Report Oneka Lake Boulevard and Harrow Avenue Improvements Hugo, Minnesota WSB Project No. 010893-000 Page 9