水利水电专业外文翻译外文文献英文文献填料的填筑和保护.doc

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.填料的填筑和保护大坝填筑的方式应做到：无论哪一部分的填料填筑后，最后的基础面暴露的时间不超过72小时。填筑填料的方法还应该防止填筑材料的分离。如果合同要求在不同的地段填筑不同的填料，承包商在施工时应防止不同类型的填料相互混淆。万一工程师认为过多的不同类型填料相互混合了，这些被混合的材料应当清除并运到废料场去，且用新的填料取代。任何沉积在填筑面上劣质材料在填筑下层填料前都应该清除掉。如果先一层填料已经变干、饱和、因暴露在外受到破坏、有其他物质散落进来、因机械运输遭到破坏、有风吹的外来物沉积或者其他方式的破坏，都不得在其上填筑新一层填料。在填筑新填料前，所以受到破坏的物质或者杂质都应该清除，清除的深度至合格的标准材料出露为止。在填筑新一层的填料前，每一层填料都必须经工程师认可。所有填料填筑应该按照统一层厚进行填筑，这个厚度不能超出此后规定的许可厚度，并且按照循序渐进的方式沿着堤坝中心线近似水平地向前推进。除非另有规定或者另有指示，任何填筑部分都不应该比相邻层的填料高出3in以上，除非工程师许可。由于此种填筑而形成的从一个高程到另外一个高程阶梯坡度不能比1:3（v:h）还陡，也不能提1:4（v:h）还缓。除非图纸有专门的注明或者有其他的规定，所有填筑面，无论是心墙上游还是下游，都应该按照与大坝中心线形成一定角度的坡面型式填筑，以心墙下游边坡为坡面分界线，便于排水，以防积水。任何临时填筑面的排水斜坡不应超出1：30，最高位置应该是心墙的下游边。由于现有坝顶开挖的特殊几何形状，如果坡面朝着心墙下游边倾斜，承包商应采取必要的措施防止侵蚀的材料被冲刷进了心墙下游的过滤层。任何因排水或者其他原因受到污染的过滤层表面材料在填筑下一层前应该清除掉，并用心的滤料代替。大坝填筑的方式要尽可能最大长度地向前铺设，至少1500ft；同时还应保证临时施工坡面不能穿越大坝的轴线，除非工程师许可那样。如果工程师许可临时施工坡面穿越大坝轴线，那么坡比应为1:5（v:h）。后来再在此坡面填料时，应将此坡面削成台阶式的，一避免出现羽毛边，每一阶级的厚度与铺设层厚度一样。承包商应将每一层填料一直铺完至边墩相连处或其他临界结构物处，紧靠倾斜的基础面，并保证按照规定将各处的填料都压实。承包商不能让某些地方的填筑滞后或超前正常速度以致形成羽毛边，除非这些地方已事先进行了填筑用以覆盖灌浆面。如果允许承包商使用砂砾或砂岩填料，不能在同一填筑层使用两种填料的混合物。在大坝填筑的相邻层次激活相邻地段可以将两种填料中的任何一种间隔铺设。承包商有责任保护临时填筑面部不受到破坏或者侵蚀。在美国工作日结束或遇下雨时，填筑面应该用平轮压路机将天真