Placing and protecting fillFill shall be placed so that mo part of the final foundation surface remains exposed for more than 72 hours.Fill shall be placed in such methods as will prevent segregation of the material.Where the Contract requires the placing of different types of fill in separate zones,the Contractor shall carry out the work so as to prebent mixing of different types of fill.Shoud there be ,in the opinion of the Engineer, any excessive mixing of different types of fill , such mixed materials shall be removed to a spoil tip and replaced with fresh fill.Any undesirable material accumulated on the fill surface shall be removed before placeing the next layer of fill.No fill material shall be placed on a previous layer of that has dried out,become saturated or in any way deteriorated by exposure or by spilling of other material or disterbance by mechanical transport or by deposition of wind blown particles or by any other means. Before fresh fill material is placed aoo such deteriorated fill or foreign material shall be removed to a depth at which material of an acceptable standard is exposed. The surface of each layer is to be approved by the Engineer before the next layer is placed. Any fill shall be placed in uniform layers not greater than the approved thickness as specified hereafter and in an orderly sequence approximately horizontal along the centreline of the embankments.Except where specified of directed otherwise, no portion of any embankment shall be stepped more than 3 feet higher than any immediately adjacent portion except where permitted by the Engineer and the slope formed by such steps shall not exceed 1V:3H and not less than 1V:4H from one level to another.Except as shown on the Drawings or as otherwise directed, all fill placement surfaces shall be sloped at right angles to the centerline of the embankment in both the upstream and downstream direction from the downstream edge of the core so as to allow run-off and prevent the accumulation of water. The drainage slope on the temporary surface of anny zone shall not exceed 1 on 30 and the highest point shall be de downstream edge of the core.Where,due to the specified geometry of the excavation into the top of the existing embankments, the surface slope is towards the downstream edge of the core, the Contractor shall take such measures an necessary to prevent erosion of fine material being washed into the filter zones downstream of the core. Any surface layer of filter material contaminated by such drainage or other cause shall be removed and replaced with fresh filter material before placing the next layer above. Construction of any one embankment shall be carried out over the maximum possible length,mo less than 1500 feet,of that embankment in such a manner that mo temporary construction slope crosses the axis of the embankment except as approved by the Engineer. Where a temporary constrction slope crossing the axis of the embankment is permitted by the Engineer it shall be formed at a gradient of 1V：5H. When subsequently placeing material against this slope it shall be cut back in steps equal to the layer thickness to avoid feather edges. The Contractor shall complete each layer of fill fully up to the abutment contacts and structures and against sloping foundations and ensure that the fill is compacted an specified throughout. The Contractor shall not allow the fill in those areas to lag behind or to get ahead of the normal fill placing operations and form feather edges, except where fill has been placed in advance to cover grouted surface.Where the Contractor is allowed to use either grvel fill and /or sandstone no intermixing of the two materials in a layer shall be allowed. The Constractor may place either of the materials in adjacent layers or sections of the embankment.The Constractor shall be responsible for protecting temporary fill surfaces against damage of erosion. At the end of each working day,or if it start to rain ,the surface of the fill shall be made smooth and compacted with a smooth drum roller with a drainage slope to induce runoff from the filled areas and leave no areas that can retain water. Where necessary, grips,drainage ditches and the like shall be formed to assist drainage and to prevent runoff from damaging placed material.Runoff from heavy rain shall be controlled to prevent gully erosion of the placed fill. Any gully erosion shall be repaired with material compacted in accordance with the Specification, and eroded surfaces shall be restored and graded to ensure a proper bond with new fill placed on them.Any eroded material other than gravel and any contaminated material shall be removed from the embankment and placed in designated spoil tips. In particular the Contractor shall ensure that no material is washed into filter or drain material.Where placing of the filter material of drain material is not continuous ,the Constractor shall protect such filter or drain materials by a 2 foot thick layer of course filter material or in such other manner approved by the Engineer,and the Contractor shall maintain the protective layer.The Contractor shall keep the work free from standing water to prevent damage to the fill material. When working below the surrounding level, the Contractor shall ensure that material from adjacent areas does not contaminate the fill material,and that runoff does not flow onto the fill.The Contractor shall arrange the timing and rate of placing fill material in sucn way that no part of the workes is over stressed,weakened or endangered. Any part of the fill that be comes saturated or attains excessive moisture content or that is rendered unsuitable due to poor surface drainage, uncontrolled traffic,or for any other reason, shall be excavated and removed to a spoil tip and replaced by fresh fill .If permitted by the Engineer, such fill may be scarified and re-compacted.Unless otherwise approved by the Engineer unrestrained edges of fill, whether for temporary or permanent slops, shall be overbuilt as necessary to allow full compaction to be achieved within defined limits of the fill. The excess material shall be trimmed and removed to leave a regular compacted surface.Slope exposed to view,including riprap and downstream protection slopes, shall be dressed to neatly appearing final surfaces matching the existing slopes.Temporary access ramps shall be removed when work in that area is completed. Any ramps or other areas within the limits of an embankment which, in the opinion of the Engineer have been over-compacted or damaged by the concentrated use by construction equipment,shall be reworked and re-compacted or,if the Engineer requires,shall be excavated, removed to spoil tip and replaced by the fresh fill.When necessary the surface of the layer of fine grained fill material(rolled clay,rolled silt Type A and B ,Rolled Sandstone Type A and B) shall be sprayed with water to prevent drying out and to maintain the correct uniform moisture content prior to placing the next layer.The Contractor shall ensure that a good bond is achieved between layers of filland unless otherwise directed, previously compacted layers of fine grain materials shall be harrowed, scarified or otherwise roughened to depth of at least 3 inches and made suitable for covering with future layer of fill.填料的填筑和保護(hù)大壩填筑的方式應(yīng)做到：無論哪一部分的填料填筑后，最后的基礎(chǔ)面暴露的時(shí)間不超過72小時(shí)。填筑填料的方法還應(yīng)該防止填筑材料的分離。如果合同要求在不同的地段填筑不同的填料，承包商在施工時(shí)應(yīng)防止不同類型的填料相互混淆。萬一工程師認(rèn)為過多的不同類型填料相互混合了，這些被混合的材料應(yīng)當(dāng)清除并運(yùn)到廢料場去，且用新的填料取代。任何沉積在填筑面上劣質(zhì)材料在填筑下層填料前都應(yīng)該清除掉。如果先一層填料已經(jīng)變干、飽和、因暴露在外受到破壞、有其他物質(zhì)散落進(jìn)來、因機(jī)械運(yùn)輸遭到破壞、有風(fēng)吹的外來物沉積或者其他方式的破壞，都不得在其上填筑新一層填料。在填筑新填料前，所以受到破壞的物質(zhì)或者雜質(zhì)都應(yīng)該清除，清除的深度至合格的標(biāo)準(zhǔn)材料出露為止。在填筑新一層的填料前，每一層填料都必須經(jīng)工程師認(rèn)可。所有填料填筑應(yīng)該按照統(tǒng)一層厚進(jìn)行填筑，這個(gè)厚度不能超出此后規(guī)定的許可厚度，并且按照循序漸進(jìn)的方式沿著堤壩中心線近似水平地向前推進(jìn)。除非另有規(guī)定或者另有指示，任何填筑部分都不應(yīng)該比相鄰層的填料高出3in以上，除非工程師許可。由于此種填筑而形成的從一個(gè)高程到另外一個(gè)高程階梯坡度不能比1:3（V:H）還陡，也不能提1:4（V:H）還緩。除非圖紙有專門的注明或者有其他的規(guī)定，所有填筑面，無論是心墻上游還是下游，都應(yīng)該按照與大壩中心線形成一定角度的坡面型式填筑，以心墻下游邊坡為坡面分界線，便于排水，以防積水。任何臨時(shí)填筑面的排水斜坡不應(yīng)超出1：30，最高位置應(yīng)該是心墻的下游邊。由于現(xiàn)有壩頂開挖的特殊幾何形狀，如果坡面朝著心墻下游邊傾斜，承包商應(yīng)采取必要的措施防止侵蝕的材料被沖刷進(jìn)了心墻下游的過濾層。任何因排水或者其他原因受到污染的過濾層表面材料在填筑下一層前應(yīng)該清除掉，并用心的濾料代替。大壩填筑的方式要盡可能最大長度地向前鋪設(shè)，至少1500ft；同時(shí)還應(yīng)保證臨時(shí)施工坡面不能穿越大壩的軸線，除非工程師許可那樣。如果工程師許可臨時(shí)施工坡面穿越大壩軸線，那么坡比應(yīng)為1:5（V:H）。后來再在此坡面填料時(shí)，應(yīng)將此坡面削成臺(tái)階式的，一避免出現(xiàn)羽毛邊，每一階級(jí)的厚度與鋪設(shè)層厚度一樣。承包商應(yīng)將每一層填料一直鋪完至邊墩相連處或其他臨界結(jié)構(gòu)物處，緊靠傾斜的基礎(chǔ)面，并保證按照規(guī)定將各處的填料都?jí)簩?shí)。承包商不能讓某些地方的填筑滯后或超前正常速度以致形成羽毛邊，除非這些地方已事先進(jìn)行了填筑用以覆蓋灌漿面。如果允許承包商使用砂礫或砂巖填料，不能在同一填筑層使用兩種填料的混合物。在大壩填筑的相鄰層次激活相鄰地段可以將兩種填料中的任何一種間隔鋪設(shè)。承包商有責(zé)任保護(hù)臨時(shí)填筑面部不受到破壞或者侵蝕。在美國工作日結(jié)束或遇下雨時(shí)，填筑面應(yīng)該用平輪壓路機(jī)將天真嗎碾壓光滑形成一個(gè)排水坡面，便于將填筑區(qū)域的水引走，不留下任何積水帶。必要時(shí)，挖一些溝壑幫助排水，防止流水損壞填筑材料。要控制大雨形成的徑流，以防止排水溝對(duì)填筑面/材料的侵蝕。因排水溝而找出的任何輕視都要用合適的材料按照規(guī)范要求碾壓、修補(bǔ)。被侵蝕的表面應(yīng)該恢復(fù)成原狀，形成的坡面應(yīng)保證合適的粘結(jié)度，使得填于其上的材料能與之很好的結(jié)合。除礫石外，任何侵蝕的材料和污染的材料都應(yīng)該從堤壩清除掉，并運(yùn)到指定的棄料場。承包商尤其要注意，不能允許材料沖進(jìn)了過濾層（材料中）或排水層（材料里）如果過濾料或排水料的填筑不連貫時(shí)，承包商應(yīng)用2in厚的粗過濾料將它們包含起來，或者用工程師許可的其他方式，承包商應(yīng)維持保護(hù)。承包商應(yīng)保持施工區(qū)域沒有積水以免對(duì)填料造成損壞。如果施工在周圍高程以下，承包商應(yīng)保護(hù)毗鄰地區(qū)的材料不會(huì)污染填筑料，徑流不會(huì)流到填料上。承包商應(yīng)安排好填筑填料的時(shí)間和進(jìn)度，保證工程的任何部分都不要承壓過重、過輕或者受到破壞。如果填筑的任何一部分已經(jīng)飽和、水分過多，或因表面排水不好、車輛過多的碾壓及其他原因找出填筑不合適，所以這樣不合適填筑應(yīng)該挖掉，運(yùn)到棄料場，并用新材料代替填筑的原處。如果得到工程師許可，可將這樣的填筑翻松并重新壓實(shí)。除非工程師另有批準(zhǔn)，沒有限制的填筑邊，無論是臨時(shí)坡面還是永久坡面，都應(yīng)該做必要的修飾以便在規(guī)定的填筑范圍內(nèi)獲得足夠的壓實(shí)度。多余的填筑邊料應(yīng)予清除并對(duì)邊角加以修整，保留正規(guī)的壓實(shí)面。暴露于外的觀賞面，包括拋石護(hù)岸和下游保護(hù)面，應(yīng)該鋪設(shè)整齊劃一，最終的可視面應(yīng)和原有的坡面（加高前的）相匹配。某一區(qū)域的施工完成以后，通向兩個(gè)工作區(qū)的臨時(shí)坡路應(yīng)當(dāng)拆除。對(duì)于大壩填筑范圍內(nèi)的任何坡面便道或其他施工區(qū)域，如果工程師任務(wù)已經(jīng)被施工設(shè)備的頻繁使用而碾壓過多或者毀壞了，承包商應(yīng)該重新作業(yè)，重新壓實(shí)；如果工程師要求，應(yīng)將其挖除并運(yùn)到棄料場，且要求用新的替代材料填筑完好。必要時(shí)，要再填筑下一層填料于細(xì)顆粒填料（碾壓粘土、碾壓粉土A型和B型、碾壓砂巖A型和B型）層上之前，噴灑水以防止干燥并維持統(tǒng)一而有恰好的含水量。承包商應(yīng)確保各填料層之間有良好的粘結(jié)度，除非另有規(guī)定，以前的細(xì)顆粒料填筑層耙松、翻松或者鑿毛至至少3in的深度，以適合覆蓋下一個(gè)填筑層。