A study on hydraulic back analysis for an urban tunnel site and stability analysis based on hydro-mechanical coupling analysis

도심지 터널 용출수 발생구간에서의 수리 역해석 및 수리-역학 연계해석을 통한 안정성 해석 연구

  • 박인준 (한서대학교 토목공학과) ;
  • 송명규 (단우기술단, 기술연구소) ;
  • 신휴성 (한국건설기술연구원, 지하구조물연구실) ;
  • 박용수 (포스코건설)
  • Published : 2008.12.26

Abstract

Excessive amount of groundwater flowed into tunnel, while constructing Incheon international airport railway. Tunnel passes under subway line no. 2 with only 1.76 m below. To protect the existing structure, TRcM excavation method was applied. As station and construction shaft are already constructed, which are located back and forth of TRcM section, 86.4 ton per day of groundwater inflow is against expectation. To identify mechanism of excessive water inflow, hydraulic back analyses were performed. Then, hydro-mechanical coupled analysis were also performed with the hydrogeologic parameters identified, whose results are investigated for checking the stability of adjacent structures to the tunnel under construction. And a number of mechanical analyses were also performed to check the hydro-mechanical coupling effect. The result from the mechanical analysis shows that subsidence and tunnel ceiling displacement will be 0.85 mm and 1.32 mm. The result of hydro-mechanical couple analysis shows that subsidence and maximum tunnel ceiling displacement will be 1.2 mm and 1.72 mm. Additional displacements caused by groundwater draw down were identified, however, displacement is minute.