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3.4 PROTECTION OF COMPLETED LIFT AND PREPARED GROUND SURFACE <br /> A. After completion of a lift or ground surface preparation,all unnecessary traffic shall be kept off.Should <br /> it be found necessary to haul over the completed lift or prepared ground surface,the Contractor shall <br /> drag and roll the traveled way as frequently as may be necessary to remove ruts,cuts,and breaks in the <br /> surface.All cuts,ruts,and breaks in the lift or surface that are not removed by the above operations <br /> shall be repaired.Winter earthwork operations are common along the Front Range and can be <br /> performed satisfactorily by adopting certain procedures and taking prudent precautions. <br /> B. Generally,earthwork operations can be conducted whenever the water being used to moisture <br /> condition the fill does not freeze prior to being mixed with the fill and,after mixing,the moisture- <br /> conditioned fill does not freeze prior to compaction or prior to placing the next lift. These conditions <br /> can obviously be met when temperatures are above freezing and can even be met when temperatures <br /> are below freezing due to direct sunshine and/or due to the fill material being warmer than the ambient <br /> temperature.The exact temperature and weather limitations can be determined by the Contractor and <br /> the Engineer as winter operations progress. <br /> C. At the end of each work day,the exposed active fill area should be covered with a minimum six-inch <br /> thick,loose,dry lift of soil which will serve as an insulating layer to limit freezing. <br /> D. At the beginning of each work day,the loose lift form the night before should be inspected for evidence <br /> of freezing. If any frozen soil exists,it should be removed to the full depth of freezing,even if frozen soil <br /> extends beneath the loose lift and into previously compacted soil.After removing frozen soil,the <br /> exposed surface should be scarified with a disk or pulvamixer.Earthwork operations can then proceed <br /> as normal. If the loose lift does not contain any frozen soil,then it can be moisture conditioned and <br /> compacted in place without the need for removing it. <br /> E. Any portion of the fill which is not being actively worked but becomes subject to freeze/thaw cycles <br /> should be scarified and re-compacted prior to placing additional fill even if it is not frozen at the time <br /> work is resumed in that area. <br /> F. Also at the beginning of each work day,the borrow source should be inspected for evidence of freezing. <br /> All frozen materials should be stripped form the borrow source and not used in the fill. Pre-wetting the <br /> borrow source is not desirable for winter construction. <br /> G. Earthwork can be conducted after snowstorms providing that the snow is removed from the borrow <br /> source and from the active fill area and providing that the other conditions outlined above are met. <br /> 3.5 FILL <br /> A. Obtain the Engineer's review of the surface to be filled and the fill material to be used prior to placing <br /> permanent fill. <br /> B. Do not place frozen fill,or fill mixed with snow or ice. <br /> C. Low Permeability and Permanent Embankment fill shall be placed in horizontal lifts and each lift <br /> compacted to the specified relative compaction for the full width.At all times during construction,the <br /> surface of the fill shall be graded to prevent ponding of water and maintained for storm water drainage. <br /> D. Fill placement shall occur by routing the hauling and spreading units approximately parallel to the axis <br /> of the fill.As far as practical, hauling units shall be so routed that they do not follow in the same paths, <br /> but split their tracks evenly across the surface of the fill to enhance compaction. <br /> E. For each fill material,the respective borrow area shall be blended to achieve a homogenous fill across <br /> the embankment without lenses,pockets,or zones of different materials. <br /> Loloff Slurry Wall 3123 00-4 <br />