关键词: 含硬岩层, 液压打桩锤, 收锤标准, 贯入度, 抗压承载力性能

Abstract: Due to the high damage rate of driven piles under geological conditions containing hard rock strata, the conventional practice is to first create mechanical pilot holes, and then grouting in the holes to form piles. This project innovatively uses a submerged hammer to fill soil into the pilot holes, and then uses a hydraulic pile hammer to drive piles. It is necessary to explore the hammer driving criteria under on this condition. The result of the DANISH formula was s=70mm at the last three blows, which is too large, and the reference value provided by the Guangdong standard is difficult to accurately select. The result of the Hilley formula is s=17.5mm, which is relatively close. It is assumed that the PHC500 pipe pile has a wall thickness of 125mm, and the penetration rate of each of the last three blows is no more than 20mm. Combined with the test results of the axial compressive resistance, it is shown that the hammer driving criteria can not only reduce the loss rate but also exert the normal potential of axial compressive resistance.

Key words: Hard Rock Formation, Hydraulic Pile Hammer, Hammer Driving Criteria, Penetration, Axial Compressive Resistance