Abstract:In order to meet the increasing demand for bored piles with 3m diameter and complete the series sizes of full hydraulic percussive reverse circulation drilling rig, YCJF-30 full hydraulic percussive reverse circulation drilling rig with the nominal drilling diameter of 3m was developed. The mechanical, electrical and hydraulic technology is integrated into the YCJF-30 drilling rig, with the unique hydraulic cylinder for impact, the differential double-drum hoist for increasing lifting ability, and the heavier 20t impact hammer for high rock-breaking efficiency. The drilling rig is equipped with hydraulic step-walk crawlers, which can be conveniently shifted to align with the well collar. The drilling tower is controlled by hydraulic cylinders, which are stable, safe and labor-saving. Furthermore, air-lift or pump reverse circulation can be adopted to discharge drilling cuttings with high carrying ability. The production test showed that the drilling rig has reasonable and advanced parameters, reliable performance, high degree of automation, simple operation, easy maintenance, low cost, and can be used for drilling of various formation.