Since the 30-year-old facility is expected to surge from 10.5% to 23.9% in 10 years, the new evaluation system is needed to establish efficient maintenance system for securing the safety and extending the life span of existing facilities. In this study, Delphi and AHP(Analytic Hierarchy Process) was conducted to provide a systematic new evaluation system for the NATM tunnel, which is the most frequently constructed structure of the existing tunnel. Since the existing assessment systems are limited in scope of evlauatuon criteria, the survey was conducted in conjunction with closed questionnaires on existing items and open questionnaires for eliciting new items. In results, suitable evaluation factors were derived for the NATM tunnel through the validation of the survey results. Also after calculating weighted value of the derived assessment item using AHP technique, a new evaluation system is proposed to meet the characteristics of the NATM tunnel, so that they can be used as reference materials for revising and supplementing detatiled guidelines in the future.

Abstract
 1. 서 론
 2. 본 론
  2.1 안전성 평가항목 도출 방법
  2.2 NATM 터널의 평가체계 도출 결과
 3. 결 론
 References

• 박광림(한국시설안전공단 진단본부 부장) | Kwang-Rim Park Corresponding author
• 정지승(동양대학교 철도건설안전공학과 교수) | Jee-Seung Chung