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<br /> <br /> <br />Geotechnical Report <br />2021 Street Improvements <br />Hugo, Minnesota <br />WSB Project No. 015887-000 Page 8 <br /> <br />Based on our borings dewatering during excavation and installation of utilities should be anticipated. <br /> <br />4.6 Dewatering <br />Groundwater was encountered in the borings at relatively shallow excavations. Groundwater could enter <br />the excavations during placement of utilities. Where excavations are to depths of less than 2 feet below <br />the groundwater table, sumps and pumps can likely be utilized for dewatering. Where excavations <br />exceed 2 feet below the groundwater table, we recommend consideration of sand point wells to dewater <br />the area. <br /> <br />4.7 Construction Considerations <br />Good surface drainage should be maintained throughout the work so that the site is not vulnerable to <br />ponding during or after a rainfall. If water enters the excavations, it should be promptly removed prior to <br />further construction activities. Under no circumstances should fill or concrete be placed into standing <br />water. <br /> <br />Soil corrections at this site for pavement subgrades may not be continuous. We recommend tapering the <br />fills back to native soils at a ten to one (10:1) slope. <br /> <br />4.8 Construction Safety <br />All excavations should comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P <br />“Excavations and Trenches”. This document states that excavation safety is the responsibility of the <br />contractor. Reference to this OSHA requirement should be included in the job specifications. <br /> <br />The responsibility to provide safe working conditions on this site, for earthwork, construction, or any <br />associated operations is solely that of the contractor. This responsibility is not borne in any manner by <br />WSB. <br /> <br />4.9 Cold Weather Construction <br />It is our understanding that construction is unlikely to occur during the winter months. However, if the <br />construction does continue into the winter months, we recommend the following guidelines. <br /> <br />Roadbed embankments should not be constructed during periods when the embankment material freezes <br />while being placed and compacted, nor should embankment material be placed on soil that is frozen to a <br />depth greater than 4 inches. When the soils are frozen to a depth exceeding 4 inches, at a time when <br />weather conditions are such that embankment construction could be co ntinued without the material <br />freezing as it is being placed and compacted, the contractor may be permitted to excavate the frozen soil <br />and proceed with the embankment construction for so long as the weather will permit. The frozen soils <br />should be pulverized or replaced with other suitable soils to construct the embankments as specified. <br />Only unfrozen fill should be used. <br /> <br />4.10 Field Observation and Testing <br />The soil conditions illustrated on the Logs of Test Borings in Appendix A are indicative of the conditions <br />only at the boring locations. <br /> <br />WSB also recommends a representative number of field density tests be taken in engineered fill and <br />backfill placed to aid in judging its suitability. Fil l placement and compaction should be monitored and <br />tested to determine that the resulting fill and backfill conforms to specified density, strength or <br />compressibility requirements. We recommend at least one compaction test for every 150 feet of utility <br />trench at a vertical interval of two (2) feet. Prior to use, proposed fill and backfill material should be <br />submitted to the WSB laboratory for testing to verify compliance with recommendations and project <br />specifications. <br /> <br />Dynamic Cone Penetrometer (DCP) tests can be completed in the aggregate base in lieu of density <br />testing. We recommend following MnDOT Specification 2211.3.D.2.c.