7815 E GLEN DR 2016-01-01 MF Import

recompacted and approved, the roadway can be brought to grade with structural fill placed as described in the Structural Fill section of this report. In our opuuon, stable construction slopes should be the responsibility of the contractor and should be detemuned during construction based on the encountered conditions at that time. , For estimating purposes, however, we anticip�te that temporary, unsupported cut slopes in the very loose to medium dense fill sediments and native site soils can bc: made a[ an overall slope of approximately 1H:1V (Horizontal:Vertical). Temporary cut slopes in the dense to very dense, unweathered lodgement dll sedimenu can be made at an overall slope of approximatcly O.SH:1V. As is rypical with earthwork operarians, some sloughing and raveling may occur and cut slopes may have to be adjusted in the field. Cumpaction of the excavated slope faces (fil: or medium dense, weathered lodgement till) with the excavator bucket ot a plate co�upactor is reconur.ended to densify the slope faces and improve stabiliry. Plastic sheet covering is also recommended to reduce surface er�sion. In addition, �VISHA/OSHA regularions should be followed at all times. The on-site soils contain a high percentage of fine-grained material which makes them moisture-sensitive and subject to disturbance when wet. The contractor must use caze during site preparation and excavation procec!ures so that the i�nderlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. Consideration should be given to protecting access and staging areas with an appropriate section of crushed rock. Permanent slopes on the site should not exceed a gradient of 2H:1V. Vegetation should be re- established on these slopes as soon as possible to reduce erosion. 10.0 STRUCTURAL FILL Structural ftll will be necessary to establish desired grades at the site. All references to strucr,�ral fill in this report refer to subgrade preparation, fill type, placement, and compaction of materials as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. If fill is to be placed en slopes steeper than SH:1V, the base of the fill should be tied to firm, stable subsoil by appropriate keying and benching which W�ould be established in the field to suit the particular soil conditions at the time of grading. The keyway will act to embed the toe of the new fill into the hillside. Generally, the keyway for hillside fills should be at least 8 feet wide and cut into the lower, native, medium dense to dense, lodgement till sediments. Level benches would then be cut horizontally across the hill, following the contours of the slope. No specific width is required for the benches, although rhey are usually a few feet wider than the dozer being used to cut them. All fills proposed over a slope should be reviewed by our office prior to construction. 9