This paper presents a special case in Qingdao, the geotechnical engineering exploration is carried out after damming cofferdam by artificial riprap in continental shelf region, hydraulic filling silt, silty soil and sandy soil and foundation treatment by vacuum preloading. The drilling construction technologies and corresponding technological measures are introduced. Rotary drilling and drilling by mud protection are adopted; in gravel and riprap formations, drilling with casing and air compression hammer percussive drilling technologies are used for the guide hole with DTH hammer engineering drill and air compressor.