Abstract: This paper extended the photography technique to multi-hole occasion and proposed the connection evidences from aspects of orientation and geological characteristics. It also applied the method to foundation investigation of Longjiang Super-major Bridge to test its reliability. It chose three boreholes on the same side of the bridge, on the basis of analyzing and calculating the parameters including spatial position, geological characteristic, orientation and width of the discontinuities. It then contrasted and screened the discontinuities according to connectivity principle, and finally got three discontinuities between two boreholes and two discontinuities among three boreholes. The discontinuities that could be connected own the similar orientations and their spatial positions meet the requirements of lying in the same plane. In addition, the rocks that formed or around the discontinuities own the similar characteristic. The results indicate that it is practicable to apply discontinuity connection method to the engineering.

Key words: borehole photography, discontinuity connectivity, similarity, engineering verification