1、施工准备
 （1）首先确定钻孔桩位，修通旱地位置便道，为施工机具、材料运送提供便利。
 本合同段部分桥梁墩身桩基础位于水中，施工时在施工位置筑岛填筑砂砾，岛面高出施工期水位1.5m，并整平夯实。如图,2-1所示。
 （2）平面桩位测量放样
 用全站仪或经纬仪进行放样，放样时对全桥桩位进行一次放样。放样结束后利用各桩位相互间距离进行钢尺测距复核，并对计算数据采用另外程序进行计算复核。测量中误差≤10mm，并报请监理工程师复核无误后埋设护桩，护桩埋设在钻孔桩纵、横轴方向，四个方向每边埋设两个护桩，第一个护桩距护筒边200cm，第二个护桩距第一个护桩距离≥600cm。
 2、泥浆制备
采用钢制泥浆槽储浆，选用优质膨润土造浆，泥浆比重控制在1.1～1.4范围。试验泥浆的全部性能指标，并在钻进中定

1, construction preparation
 (1) First, determine the place bored piles, repair location through dry pavement, as construction machinery, materials to facilitate delivery.
 Some paragraphs of this contract bridge piers in the water piles, the construction of filling in the gravel island construction building location, construction of the island surface of the water level above the 1.5m, and level the compaction. Figure 2-1 shows.
 (2) measurement of surface Pile Layout
 Setting out with a total station or theodolite, when setting out to conduct a full bridge Pile Layout. Setting out after the use of the distance between pile-bit ranging review of steel rule, and the calculated data calculated by other review procedures. Measurement error of ≤ 10mm, report to review and correct supervision engineers were laid after the piles, bored piles piles buried in the longitudinal and transverse direction, the four directions laid two piles on each side, the first piles away from the casing edge 200cm , the second piles piles away from the first distance ≥ 600cm.
 2, slurry preparation
Pulp slurry storage tank with steel, use high-quality bentonite mud, mud GDP 1.1 to 1.4 range. Performance testing of all mud, and drilling will