For this study, Inspection and test was carried out in Tunnel. After this process, Numerical Analysis was accomplished by 3D. A result of inspection and test, It couldn't find the reason why the upper slab crack was detected. The result of 3D Numerical Analysis, The reason was found that the Demage on upper slab was caused by moment change. The Moment was changed by column interval transition. To figure out the cause of cracks, we are using FEM. This Study can help developing designation and maintenance about Tunnel.

• 박재영(한국시설안전공단 일반철도팀 대리) | Park, Jae-Young
• 박광림(한국시설안전공단 일반철도팀 과장) | Park, Kwang-Lim
• 이태형(한국시설안전공단 일반철도팀 대리, 공학박사) | Lee, Tae-Hyung
• 오영석(한국시설안전공단 일반철도팀장, 토질및기초기술사, 공학박사) | Oh, Young-Seok