The active criterion strictly stipulates spacing of exploration point and lay gradient of bearing stratum for end-bearing pile,but in the site where the rock is for bearing stratum,the lay gradient of rock undulates in large extent due to sedimentary circumstance and geologic structure.

With the theory of sequence stratigraphy and seismic stratigraphy, it analyses the various types of lithologic-stratigraphic traps, their occurrence conditions and the exploration difficulty, and also proposes the exploration thinking that builds in the basement of finding o.