Research methods: Based on the geological investigation standards for passenger dedicated railway line and I level railway，this paper analyses the distortion requirement and characteristics of geological investigation for passenger dedicated railway line，and discusses the necessity of improving the geological investigation precision ， taking the angle of critical deformation and naming of the running soil.
Research results: Based on the requirement of geological investigation for I level railway，the number of boreholes for investigation of passenger dedicated railway line should be increased and the depth of borehole should be deepened. The comprehensive analysis and settlement observation are also being required. This paper brings forward the new understandings about the depth of geological investigation for passenger dedicated railway line and the selection of angle of critical deformation for the goaf ， and analyses the disadvantage factors of naming of the running soil.
Research Conclusions: With the improvement of technique standard for passenger dedicated railway line，the foundation soil deformation needs to be considered seriously. The condition of regional geology should be fully analyzed. The settlement observation on site should be regarded. The angle of critical deformation of goaf for passenger dedicated railway line should be boundary angle. The running soil should not be a type of soil in the soil classification system.
2007, Vol. 24 
