Abstract: Tunnel water inrush disasters are characterized by strong concealment, complexity, suddenness, and destructiveness. The nature, location, and scale of the disaster-causing structures can be identified by advanced horizontal drilling combined with borehole TV logging. However, traditional borehole TV is difficult to deploy in horizontal drilling, and structural planes in boreholes of any azimuth are difficult to analyze. A cable-free, storage-based TV device based on an optimization algorithm for structural planes is proposed. It can accurately calculate the structural planes in any azimuth borehole, and it can be directly connected to the drill pipe and smoothly advanced to the designed depth. The equipment was applied to the advanced prediction of a railway engineering tunnel. Eight irregular intrusion zones of diabase with widths ranging from 0.73 m to 13.8 m in front of the tunnel face and five joint fissure dense zones were identified. The tunnel water inrush disaster-causing structures belong to the intrusive contact type. The locations of the irregular intrusion zones, the attitudes of the upper and lower unconformity contact surfaces, and the positions of the fissure dense zones were obtained using the two-dimensional expansion map of borehole TV. Thus, the water inrush structure in front of the working face can be accurately described. Sections D2K189+410-414, D2K189+440-444, and D2K189+510-513 are considered to be the most dangerous potential water inrush sections, and it is suggested that drainage and support be carried out in these parts of the tunnel.