QJ250型大直径灌注桩钻孔机是郑州勘机械察厂为郑州黄河公路大桥灌注桩孔设工并试制的钻孔机械。样机由该厂进行了性能试验,并由河南省交通公路工程处第二施计队在郑州黄河公路大桥北岸进行了工业性考核。1984年11月在郑州召开了技术鉴定会。参加会议代表审查了该机全部鉴定技术文件,观看了样机施工现场表演。代表们认为,该机结构合理,功率扭矩大,具有三档 The QJ250 large-diameter cast-in-place pile drilling machine is a drilling machine designed by Zhengzhou Kanchan Machinery and Inspection Factory for the injection hole of Zhengzhou Yellow River Highway Bridge. The prototype was conducted by the plant for performance testing, and the Second Assessment Team of the Henan Provincial Highway Engineering Office carried out an industrial assessment on the north bank of the Zhengzhou Yellow River Highway Bridge. In November 1984, a technical appraisal meeting was held in Zhengzhou. Attending the meeting, the representative reviewed all the appraisal technical documents of the aircraft and watched the performance of the prototype construction site. Delegates believe that the structure of the aircraft is reasonable, the power torque is high, and it has a third gear