In some loose and unstable rock formations, problems such as hole collapse and burial often occur during drilling. How to avoid this series of problems? After several years of on-site practice and research, Tianhe Drilling Tools has found that concentric drilling tools have the widest applicability to formations. In addition to dealing with eccentricity and the formation conditions targeted by sliders, they can also deal with large blocks. For dry rocks, karst caves, etc., the depth of the pipe can reach about 100 meters, and the drilling efficiency of the pipe is fast, and it can also be used in the field of foundation piles.