Abstract: To analyze and evaluate the influence of the geological environment on the construction of tunnel engineering, investigation and analysis are conducted on the engineering geological conditions such as the topography and geomorphology, regional geological structure, stratum lithology, hydrogeology, and insitu stress of the tunnel site, and the analytic hierarchy process is used to evaluate the quality of the tunnel site. The research results show the following: (1) Affected and controlled by the geological factors such as topography, geological structure, stratum lithology, hydrogeology, and insitu stress in the tunnel site, the surrounding rock of the tunnel performs broken, waterrich, soft, and weak. Bad geological phenomena such as mud inrush, collapse, and large deformation of soft rock are easily occurred during construction process. (2) The comprehensive evaluation value of the Xinping tunnel site′s superiority and inferiority grade is 1.31, and the site′s superiority and inferiority grade is extremely poor, indicating extremelyhigh risk. (3) The reveled surrounding rock levels and geological disasters show the accuracy and reliability of the evaluation method and results of the tunnel site′s superior and inferior grade.

Key words: railway tunnel, regional geological analysis, analytic hierarchy process, mud and water inrush, pros and cons grade evaluation