武汉市建设局最近修建一座大桥中,采用钻孔灌注桩新工艺。在施工的过程中,由于爬杆式钻杆只能向一个方向转动带动钻头,每钻进20厘米便需要提升出土。出土时反转钻杆,使杆头插销脱出凹槽后用手摇卷扬机将钻头沿钻杆上提到孔口(即钻架底层)。为了使斗内土方不致落到孔内,不打开斗门出土,只好用铁锹将斗内土方挖除,这样既费力又费时,操作 Wuhan City Construction Bureau recently built a bridge, the use of bored piles of new technology. During the construction process, because the rod-type drill rod can only be rotated in one direction to drive the drill bit, it needs to be excavated for every 20 cm of drilling. When unearthed, reverse the drill pipe, make the head bolt out of the groove, and then lift the drill bit along the drill pipe with the hand winch (ie, the bottom of the drill rack). In order to make the bucket earthwork will not fall into the hole, do not open Doumen unearthed, had to dig with a shovel earthwork bucket, so laborious and time-consuming, operation