Abstract: The geological and geophysical investigations were performed to analyze the geological condition and bearing capacity aspects of Dailailong railway subgrade materials. Based on the electrical differences between the normal and the abnormal geological bodies, The Controlled Source Audio Magnetic Telluric (CSAMT) was used to identify unfavorable geological conditions of Dailailong railway subgrade material by analyzing the apparent resistivity cross-section diagram, three-dimensional diagram, shear deformation area diagram and curve diagram, and two-dimensional inversion diagram. Secondly, by using of Evd Edynamic modulus detection method, the subgrade bearing capacity of Dalailong railway subgrade was detected by analyzing the settlement value and dynamic deformation modulus of the measurement points. The results show that the subgrade slope of Dalailong railway contains sliding bodies and uncompacted sliding surfaces, and the bearing capacity of the subgrade is unevenly distributed, which requires further filling and compaction.

Key words: dailailong railway, geological and geophysical investigation, Controlled Source Audio Magnetic Telluric (CSAMT), evd dynamic modulus detection method