such as bulldozers and graders. Hand- or power-felling equipment, explosives, and fire are used whenthey make the completion of these operations easier.CAUTIONLarge-scale clearing and grubbingoperationsoften produce damagingenvironmental effects, such as increased soilerosion, reduction of atmospheric oxygen, anddestruction of wildlife habitat. Additionally,introduction of particulate matter into streamsand riverbeds causes increased siltation andalgae growth. Federal regulations may requirean environmental impact statement orassessment prior to beginning clearingoperations.To prevent these damaging effects, save as muchvegetation as possible, such as trees, grass, and otherplants, to hold the soil in place. Constructing a shallowtrench or application of plastic barriers or hay balesaround the perimeter of a project will help to containwater runoff into streams and rivers, preventingsiltation. Burning of scrubs and stumps should be doneonly when atmospheric conditions are favorable andthe material to be burned is dry, However, do NOTuse petroleum base fuels to start fires, as fuels do notburn completely and seep into the underground watertable.NOTE: A burn permit is required in all burningoperations on NCF projects to prevent wild fires andproduction of smog.When determining the methods of earthworkoperations needed, consider the following factors:. The. The. The. The. Theacreage to be clearedtype and density of vegetationphysical features of the landexpected weather conditionstime available for completion of the jobFor best results, a combination of methods shouldbe used in a sequence of operations. Use the methodmost suitable and effective for the job.EQUIPMENTKnowing your equipment, its limitations, and itsoperating characteristics is part of the knowledge youneed to know to be an efficient EO on earthmovingjobs.Equipment production must be determined so thatthe correct amount and type of equipment is selectedfor a project. Equipment production rates are availablein the Seabee Planner’s and Estimator’s Handbook,NAVFACP-405. The handbook provides informationon estimating construction work elements andmaterial quantities, including equipment andmanpower requirements.Before you begin earthmoving operations, it isoften necessary to remove overgrowth, boulders, andother obstructions. Also, you often have to build adrainage system, so the construction site will drain.These operations are carried out with bulldozers,scrapers, graders, and similar equipment.The load, hauled by a scraper, is usually referredto as either heaped or struck (fig. 15-63). Whenmoving earth, take a full, heaped load and make itFigure 15-63.-Heaped and struck load.15-38
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