_GENERAL DOCUMENTS - C1981017 (216)

Home Browse Search

OW. SECTION 3 - HIGH ,THICK FILL, ROAD GENERAL: A typical road fill constructed where excessive quantities of material were available or where topographic conditions did not allow construction of the road in a cut. The fill was probably built using side-cast method. It was not compacted. Slopes of fill are close to the angle of repose. It has to be expected that foundations of the fill were not prepared ; vegetation was not removed , topsoil was not stored. On steep slopes, fill was not keyed into the foundation. STABILITY AND OTHER PROBLEMS: Stability of the fills is marginal ; it can be assumed that factors of safety are close to unity. For any analytical considerations, F.S. = 1. 1 should be considered for current conditions. Incipient stability problems may be indicated by tension cracks close to the fill crest. Occurrence of ground water may seriously influence the stability of the fill . Erosion, gullying , ri l l ing and sloughing of the fill surface are common. RECLAMATION CONCEPT: Flatten the fill surface to a slope of 1.5 1 or flatter. Prevent erosion, gullying and rilling by careful surface drainage. Vegetate. METHOD OF RECLAMATION: Construct a pioneer road to the toe of the fill , if not accessible. Road necessary for dozer and backhoe only. At the design toe of flattened fill , remove vegetation and topsoil from area of future fill expansion. _Store topsoil . Whenever the side slope of natural ground exceeds 3 : 1 (33 percent) , the existing ground will be stepped so that the fill can be keyed into it. The keyway shall be a minimum 10 feet in width and it shall begin at the design toe of the reconstructed fill. Natural ground flatter than 3 : 1 shall be scarified. Material from the upper part of fill will be pushed down the slope of the fill to the projected toe. Any organic material , coal , frozen material will be disposed of. The material will be spread out in lifts not exceeding 12 inches in thickness. Each lift ( payer) will be completed , levelled and com- pacted evenly by routing the hauling and levelling equip- ment over the entire width of the embankment. Erosion control measures will be taken to eliminate the possi - bility of surface erosion, gullying and Tilling. The crest of the reconstructed fill shall be rounded and shaped to eliminate sharp changes of the slope. Vegetation cover will be established on the surface of the reconstructed fill .