Construction method for deep, large and large-diameter hard rock hydraulic hob bottom-expanding cast-in-place pile in deep and thick reclamation area

The invention relates to a deep and large-diameter hard rock hydraulic hob bottom-expanding cast-in-place pile construction method in a deep and thick reclamation area, which comprises the following steps of: 1) forming a hole in a soil layer section, sinking a steel sleeve into a soil layer, and taking out soil and stones; (2) rock-socketed straight hole section drilling is conducted, and rock breaking and deslagging are conducted through a drilling machine; (3) hard rock underreaming is conducted, and underreaming is conducted on the bottom of the straight hole section through an underreaming drill bit; and (4) pile body concrete is poured. According to the method, bottom expanding can be conducted in the hard rock, it is guaranteed that the filling pile in the reclamation area has high compression bearing capacity, and building safety is guaranteed. 本发明涉及一种深厚填海区深长大直径硬岩液压滚刀扩底灌注桩施工方法，包括以下步骤，1)土层段成孔，将钢套管下沉至土层中，将泥土和石块取出；2)嵌岩直孔段钻进，通过钻机进行断岩和排渣；3)硬岩扩底，通过扩底钻头进行直孔段底部扩底；4)桩身混凝土灌注。本发明能够在硬岩中进行扩底，确保填海区灌注桩具备较高的抗压承载力，保证建