1321 COLBY AVE 1988 PARKING GARAGE AND MEDICAL OFFICE BUILDING Geotech Report 2018-01-02 MF Import

Everett General Hospital & Medical Center W-5557 29 March 1988 Page 10 information, it appears that temporary excavations of up to 15 to 20 feet may be required to achieve design foundation subgrades. The contractor should be prepared to manage seepage from cut faces as previously mentioned. Temporary excavations may be assumed at an average slope of 1H:1V (Horizontal :Vertical) for planning purposes. The actual safe slope of temporary excavations should be the responsibility of the contractor, and will vary depending upon soil and ground water conditions encountered at each location. Temporary excavation slope stability is a function of many factors including soil type, density, inclination, depth, the presence of ground water and the length of time the cut is open. As the length of time the excavation is open increases, the '. ikelihood of bank failure increases. For this reason, temporary slope safety should remain the responsibility of the contractor, who is present at the site, able to observe changes in the site soil conditions, monitor the performance of the excavation, and modify construction activities to reflect the site and soil conditions. In any case, cut slope inclination and shoring should conform to applicable Federal, State and/or local guidelines. We recommend that permanent cut slopes above the ground water table be designed with a maximum slope of 2H:1V. Slopes of this inclination may erode more easily than flatter slopes, and may require periodic maintenance. Permanent fill slopes may also be constructed with an inclination of 2H:1V. The outer surface of fill embankments should be compacted to at least 90 percent density. All slopes should be protected from runoff by berms, swales, and if necessary, an impervious cover. Permanent slopes should also be seeded and/or planted to aid in erosion control . At locations on permanent cut slopes which exhibit perched ground water seepage, it may be necessary to blanket localized areas with quarry spells to aid in erosion control. 5.0 CLOSURE The conclusions and recommendations presented in this report are based on the explorations accomplished for this study. The number, location and depths of the explorations are completed within site and scope of work constraints, so as to