【正文】 tion preparation prise: selecting drill, drill, layout. Construction of bored pile drilling rig is the main equipment, according to the geological conditions and various drilling machine applied to select conditions (2) drilling machine installation and positioning Istallation of drilling machine based if not stable, easy to produce in the drilling machine construction, pile and pile inclined inclined eccentric and other adverse effects, therefore requires the installation of foundation stability. On the formation of softer, sloping ground, be bulldozed, the pad plate or tie reinforcement. In order to prevent the pile position allowed, construction is very important to the set the center position and the correct installation of drilling machine, the rig drilling machine, first use of the power drill and near the cage with the drill pipe, moving roughly position, and then Jack rack jacking, accurate positioning, so that the lifting pulley, drill bit or fixed drill hole cards and casing center in a vertical line, in order to 中英文資料 ensure the verticality of the drilling rig. Drilling position deviation is not more than 2cm. Aligned with the pile location, with sleeper flat drill beam at the top of the tower, and symmetrical to the drill axis pulling cable wind rope. (3) buried tube Underground water level below the Kong Bitu under the hydrostatic pressure to the hole collapse, and even the phenomenon of flow of sand. If you can keep the borehole wall high underground water head, increase the hole hydrostatic pressure, to prevent collapse hole, hole wall. Casing in addition to play this role, at the same time, good isolation of surface water, ground, protecting the orifice pile hole drill guide fixed (4) slurry preparation Drilling mud is posed of water, clay ( bentonite ) and an additive position. A floating drilling waste slag cooling the drill bit, drill, lubrication, increasing hydrostatic pressure, and in the hole wall to form a slurry, partition within the bore to prevent seepage, the hole collapse effect. Modulation of the drilling mud and circulating purifying mud, should be based on the drilling method and formation conditions to determine the slurry consistency, slurry consistency should be considered stratigraphic changes or operational requirements of motor control, the mud is too thin, small, poor effect of elimination of slag wall。 slurry is too thick will weaken bit impact function, reduce drilling speed. (5) drilling The borehole is a key working procedure, in construction must strictly according to the operating requirements, in order to ensure drilling quality, attention must be given to the hole quality, must be opposite for this good midline and verticality, and pressed well casing. Must pay attention in the construction are continuously added and pumping the slurry slag ( impact type ), but also at any time to check whether there is deviation phenomenon into hole. Using the impulse or clamshell type drilling machine construction, soil due to vibration and impact near the adjacent hole stability. So the drilled hole should be timely cleaning hole, decentralization and pouring underwater concrete reinforcing cage. Drill order should also be pract