中铁十局粉喷桩技术交底.doc

交底内容：
1.  本处理地段粉喷桩桩径Ф500mm（搅拌钻头不小于Ф500mm），采用42.5级普通硅酸盐水泥。每加固1m土体掺入水泥量为55kg，单位桩长水泥用量的负值偏差应控制在8%以内，单桩水泥用量负值偏差应控制在5%以内。
2.  采用两喷四搅法施工，自上而下搅拌，自下而上喷粉搅拌，搅拌头上提喷分时的提升速度为0.5~1m/min。为保证粉体搅拌均匀，须进行全桩长复搅，复搅速度也应控制在0.5~1m/min，为保证桩底喷灰量据管道的送灰时间，提升钻具前提前喷灰，不充许先提升钻具后喷灰，停灰面为施工地面下0.5m处，复搅时管道压力不宜过大，以不堵塞出气孔为原则，防止钻孔淤泥向四周挤压形成空洞。
3.  测放桩位按设计要求进行，在确定孔位时，需经复核确认后方可进入下一施工工序，为保证桩位的准确性，桩位必须打入木桩或插入竹片作为桩位标记。
4.  下钻杆时，先使桩机安置在标定的孔位上，使钻头中心对准孔中心，杆位偏差在±5cm以内，调整桩机水平度及垂直度，保证孔斜率不大于1.5%，终孔后校正钻具，桩径偏差不得大于4%。
5.  下钻杆搅拌前要通过地面试喷清水，检查喷粉设备和管路系统、设备的压力和排量必须满足设计要求；管路系统的密封圈必须良好，各通道和喷嘴内不得有杂物。

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Cards on the table contents:
1. The processing site DJM pile diameter Ф500mm (mixing drill not less than Ф500mm), with 42.5 ordinary portland cement. Strengthening 1m per volume of soil mixed with cement 55kg, unit pile length of the negative deviation of cement content should be controlled within 8%, a negative deviation of single pile of cement consumption should be controlled within 5%.
2. Using two four-jet mixing method construction, top-down mixing, bottom-up powder mixing, spray mixing head to mention time-enhancement rate 0.5 ~ 1m/min. Stir to ensure powder, to carry out the whole pile length complex mix, complex mixing speed should be controlled at 0.5 ~ 1m/min, to ensure the spray pile ash gray, according to time of delivery channels to enhance the drill in advance of spraying dust, and not allow drilling to upgrade after the first spray gray, stop gray-0.5m below ground for the construction of office, complex mix when the pressure pipe should not be too big to not plug the pores in principle, to prevent the drilling mud to form a cavity around the extrusion.
3. Measuring Pile up by design requirements, in determining the hole, the need to be confirmed by the review into the next construction process, in order to ensure the accuracy of the Pile, Pile must be inserted into the stakes or bamboo as the pile bit tag.
4. Under the drill, the first to pile driver placed in the calibration of the holes, so that the drill center hole aligned center pole position deviation within ± 5cm to adjust the level of degree and verticality of pile driver, to ensure the slope is not greater than hole 1.5%, after the correction of the final hole drilling, pile diameter deviation of not more than 4%.
5. Stirring before the next drill pipe to the interview by spraying water, check the spray equipment and piping systems, equipment, pressure and displacement to meet the design requirements; piping system must have good seal, the channel and nozzle shall not have debris.

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