冲孔桩施工技术交底记录.doc

交底内容：
一、 工程概况
本工程桥梁钻孔桩基础总桩数为20条，施工范围从0#桥台至3#墩，其中桥台桩基双排布置，桩径为1.2m，桥墩桩基单排布置，桩径为1.5m。桥台桩基桩端持力层要求嵌入微风化铁质粗砂岩2.5米以上，桥墩桩基桩端持力层要求嵌入微风化铁质粗砂岩3米以上，并且保证桩底下面有不小于5米的完整基岩。
二、 质量标准
1、 保证项目
（1） 灌注桩用的原材料和混凝土强度必须符合设计要求和施工规范的规定。
（2） 成孔深度必须符合设计要求，桩端持力层为微风化铁质粗砂岩，遇软弱夹层时必须穿越软弱夹层。
（3） 桩身材料：混凝土等级为C30，为水下混凝土；钢筋R235级，HR235级。纵筋的混凝土保护层厚度为50mm。
（4） 分段钢筋笼中的纵筋采用对焊接长，加强筋采用双面焊；纵向钢筋接头应每隔一根错开，同一截面可接长50％的总钢筋面积的钢筋，相邻接头错开1000mm以上；螺旋箍筋与纵筋点焊，螺旋箍筋采用单面搭接焊10d接长。
（5） 采用正循环工艺成孔和清孔，桩身垂直度偏差要求不大于0.5％，桩径偏差要求不得超过-50~+100mm，桩位偏差不得大于5cm，灌注混凝土前孔底沉渣厚度要求不大于50mm。
必须按照设计要求在钢筋笼内布置好检测
Cards on the table contents:
First, project survey
Bored pile foundation of this project the total number of 20 piles, the construction units ranging from 0 to 3 # # bridge pier, which piles double layout, pile diameter is 1.2m, single-row arrangement of pier piles, pile diameter to 1.5m. Piles pile bearing stratum of iron requirements embedded in the breeze more than 2.5 meters thick sandstone, pier pile pile bearing stratum of iron requirements embedded in the breeze more than 3 m thick sandstone, and to ensure there are no less than the following pile 5 meters of the sound rock.
Second, quality standards
1, ensure that the project
(1) The pile of raw materials and the strength of concrete used must meet the design requirements and construction norms.
(2) into the hole depth must meet the design requirements, pile bearing stratum for the breeze of iron coarse sandstone, soft interlayer must be met through soft interlayer.
(3) Pile material: concrete grade C30, the underwater concrete; reinforced R235 level, HR235 level. Longitudinal reinforcement of the concrete cover thickness is 50mm.
(4) above in the longitudinal steel reinforcement cage by welding length, using double-sided welding rebar; longitudinal steel joints should be staggered at intervals of 1, the same section can be accessed 50% of the total length of the steel reinforcement area adjacent joints stagger 1000mm above; spiral reinforcement and longitudinal reinforcement welding, lap welding of spiral hoop with one side longer then 10d.
(5) using cyclic process is clear hole and hole pile verticality deviation requested is not greater than 0.5%, pile diameter deviation requests shall not exceed the -50 ~ +100 mm, Pile deviation of not more than 5cm, concrete pouring before the sediment thickness of the bottom hole required not more than 50mm.
Must follow the design layout of a good test in the steel cage