Construction method for supporting beam bottom low-clearance cast-in-place pile in trestle plate area of deep foundation pit in complex stratum

The invention relates to a complex stratum deep foundation pit trestle plate area supporting beam bottom low-clearance cast-in-place pile construction method which comprises the following steps that (1) construction preparation is conducted, trestle plate trepanning operation is conducted, and a full-rotation equipment pit bottom in-place procedure is conducted; 2) forming holes in the soil layer section, sinking the steel sleeve into the soil layer, and taking out the soil; (3) forming a hole in a rock stratum section, and carrying out processes of rock breaking, slag salvaging and hole cleaning in a sleeve; and (4) pile body concrete is poured. The construction method can replace an existing construction method of cast-in-place piles in the low clearance area at the bottom of the supporting beam in the trestle plate area of the deep foundation pit, high economic benefits are achieved, and the construction efficiency is improved. 本发明涉及复杂地层深基坑栈桥板区支撑梁底低净空灌注桩施工方法，包括以下步骤，1)施工准备，进行栈桥板开孔作业和全回转设备坑底就位工序；2)土层段成孔，将钢套管