采用泵吸反循环钻进工艺施工钻孔灌注桩,当砂石泵泵轴处于转动状态时,从壳外向壳内漏气,影响了砂石泵的真空度,从而影响了钻进效率;当泵轴不工作时,即泵轴不转动,用泥浆泵向孔内注浆时,泥浆通过泵轴向壳外漏出,这便增加了砂石泵轴承的磨损,也增多了维修次数,影响了生产效率。为 Adopting pump reverse circulation drilling technology to construct cast-in-place bored pile, when the shaft of sand pump is in rotating state, the gas leaks from the outside of the shell to the shell, affecting the vacuum degree of the sand pump and thus affecting the drilling efficiency. When the pump shaft does not work, that is, the pump shaft does not rotate. When the mud pump is used to inject the oil into the hole, the slurry leaks out of the pump through the axial shell. This increases the wear of the sand pump bearing and increases the maintenance times Productivity. for