Abstract: The distribution characteristics and laws of existing structural defects of tunnel lining are summarized based on the regular inspection data of expressway tunnels in Liaoning Province. On the basis of in-depth study of the main structural diseases of the tunnel， the extenics theory is used to extract several indicators that can accurately reveal the health status of the structure， to quantify and classify the health status， and to establish the corresponding matter-element model， so as to determine the weight of each indicator and the grade of tunnel structure disease. A health evaluation system for tunnel lining structure is constructed by combining qualitative evaluation and quantitative research， which is convenient for managers to make reasonable decisions. At the same time， based on the actual test data of tunnel engineering， the calculation and analysis of the extension model are carried out to verify the engineering applicability of the model.

Key words: tunnel stability, construction defect, analytic hierarchy process, quantitative analysis