挖孔抗滑桩施工方案.doc

挖孔抗滑桩施工

   抗滑桩是一种靠桩周土体对桩的嵌制来稳定土体，减少滑体推挤力并传递部份土推挤力的工程建筑物，对于非塑性滑坡十分有效，特别是由于两种岩层夹有薄层塑性滑层时效果明显，对于塑性滑坡，效果较差，尤其对呈塑流状滑坡体时，不宜使用。
    1.施工方法
    1.1施工中稳定滑坡的措施
    1.1.1清顺滑体坡面,铲除陡坡,陡坎壁,填塞裂缝。如有可能，可根据设计需要，先在滑体范围内处，分别浆砌圈形截水沟减少地表水下渗。
    1.1.2在抗滑桩施工范围,应大致整平地面,靠山一侧刷出宽度不小于2m的平台,另一侧如系弃碴或松散滑体,即应填平夯实,避免对桩产生侧压。
    1.1.3桩孔开挖,应视下滑力的大小,滑体的土石结构、破坏程度及地下水等不同情况，采用全面同时开挖或跳跃式间隔开挖。
    1.1.4根据地质条件,护壁可采用砼、钢筋砼、木质和喷护等方法；如地质条件许可，且开挖不深，能确保施工安全，可不支护，一俟挖至设计标高，符合桩基已置于较好的基岩上，井孔垂直且不小于设计尺寸和已达最低一层滑动面下5m以上时，立即绑扎钢筋（或下预制钢筋笼），灌注桩身砼，不容拖延时间。
    1.1.5桩孔扎口10m,内不存放大堆材料,弃碴亦应在30m以外,产生震动大的机械应设在50m以外。
    1.2桩身开挖的准备工作
    1.2.1现场核对设计,按设计测定桩位,进行施工放样。放样时要根据工地具体情况和施工可能发生的误差，每边较设计尺寸略大一些（一般为5cm）。然后整平孔口场地。
    1.2.2在井口上竖井架或摇头扒杆出碴、进料、起吊高度应高出井口3m以上，搭设临时风雨棚，做好井口排水沟。为了施工人身安全，井口设栏杆（薄壳支护高出地面者可不设）及供起吊人员装卸料用的脚踏板和井口开关门。
    1.2.3备置起吊用萝筐或特制的活底箱、桶及0.5t卷
Construction of Drilled piles

   Pile by pile is a pile embedded in soil on the system to stabilize soil, reduce the pushing force of sliding body and pass most of the engineering building soil pushing force, is very effective for non-plastic slide, especially as two kinds of rocks there are the thin layer of plastic slip effect is obvious, the plastic slide, less effective, especially for plastic flow-like landslide was when unfit for use.
    1. Construction method
    1.1 Construction of measures to stabilize landslide
    1.1.1 Slope clear smooth body, eliminate steep slopes, scarp walls, filling cracks. If possible, can be designed to require, first within the Department in the landslide were ring-shaped mortar and drainage ditches to reduce surface water infiltration.
    1.1.2 in the range of pile construction, should be roughly leveling the ground, backed by the side of the brush width of not less than 2m from the platform, the other side of the case of mucking or loose sliding body that should fill compacted to avoid the pile produce lateral pressure.
    1.1.3 Pile excavation, as the decline in force should be the size of earth and rock sliding body structure, damage and groundwater in different situations, a comprehensive excavation or jump at the same time interval excavation.
    1.1.4 According to geological conditions, Wall adopt concrete, reinforced concrete, wood, and spray methods of protection; such as geological conditions permit, and the excavation is not deep, to ensure the construction safety, why he did not care, once the excavation to the design level, consistent with pile had been placed in a better bedrock, and not less than the design of vertical borehole size and reached the minimum slip surface under a layer of 5m or more, immediately steel banding (or under the prefabricated reinforcement cage), pile concrete body, can not be delay.
    1.1.5 Pile Zhakou 10m, within the non-material storage piles, abandoned outside the ballast should be in the 30m, the mechanical vibrations generated should be located outside the 50m.
    1.2 The preparation of pile excavation
    1.2.1 spot check design, measured according to the design of pile-bit, for construction setting. When setting out the circumstances and according to the construction site for potential error, compared with the design on each side of slightly larger size (typically 5cm). And then leveling orifice site.
    1.2.2 in the wellhead on the shaft frame or shaking derrick mucking, feeding, lifting height should be more than 3m above the wellhead, erection of temporary shelter, good well-head drain. For construction safety, wellhead railing (above the ground who support shell may not) and materials for lifting personnel working with the pedals and the wellhead switch doors.
    1.2.3 Purchase lifting equipment or a special basket with carrots live bottom box, paper barrel and 0.5t