The bored cast-in-place pile is used for the foundation reconstruction of the gallery, with a design aperture of 900mm. The bearing layer at the end of the pile is moderately weathered sandstone or mudstone. The size and parameters of the pile are as follows:The actual length of the pile shall be determined according to the pile end entering the bearing layer ≥ 1000mmAccording to the construction site and geographical conditions, the construction of bored pile with rotary drilling rig is studied. Since the height of the site does not reach the construction height of the drilling rig, it is decided to use the excavator for excavation.To prevent surface water from entering the hole.After the hole cleaning reaches the design depth, the hole cleaning shall be started, and the method of slurry replacement shall be used.The secondary hole cleaning shall be carried out after the conduit is put in.When supporting the mould, ensure the verticality and flatness of the mould.