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A Study on the Stability of Slopes Reinforced with Panel-Type Retaining Walls

대절토부 사면의 패널식 옹벽보강에 따른 안정성 검토

  • Dong-wook Choi (Department of Civil Engineering, Chosun Univ.) ;
  • Jun-o Park (Department of Civil Engineering, Chosun Univ.) ;
  • Daehyeon Kim (Department of Civil Engineering, Chosun Univ.)
  • Received : 2024.04.11
  • Accepted : 2024.04.18
  • Published : 2024.06.30

Abstract

Various innovative technologies and methods are being applied to ensure the stability of steep rock slopes. However, there are design limitations concerning site ground conditions, leading to discrepancies between the designed and actual ground conditions during construction. In the case of the retaining wall in Yeosu, where the study area is located, although the construction of a 5-stage retaining wall is planned, at the current completion of the second stage, cracks on the upper part of the wall, settlement in the front of the wall, and seepage have been observed. After the completion of stages one and two, issues regarding cracks and settlement on the upper part of the wall and seepage in the front of the wall were discovered. Thus, there was a need to reevaluate the results of the existing stability assessment. It was confirmed that the issue was due to groundwater leakage, attributed to the lack of clear assessment of the colluvial soil layer during the initial design stage. Therefore, to conservatively reflect groundwater level conditions, a groundwater level contour was positioned at the top of the wall to conduct a slope stability assessment. The assessment results indicated that the safety factor during the rainy season exceeded the required value of 1.3, with a calculated safety factor of 1.31. However, during seismic events, the safety factor was determined to be 1.12, falling short of the required safety factor of 1.3. Therefore, it is suggested that the existing retaining walls constructed during stages one and two undergo reinforcement using methods such as micro-piles with grouting, and additional work should be carried out to ensure a clear assessment of the colluvial soil layer.

대절토사면 안정성 확보를 위한 보강공법에 대한 다양한 신기술, 신공법이 적용되고 있지만 현장 지반정수 고려에 대한 설계적 한계가 존재하여 실제 시공 시 설계와 현장 지반 조건이 상이한 결과가 발생하고 있다. 본 연구대상지역인 여수시 일원에 있는 옹벽의 경우 5단계 옹벽 시공예정중이나, 현재 2단계 시공완료 시점에서 옹벽 상부의 균열, 옹벽전면의 침하 및 우수 유출등이 확인되었다. 1, 2단계 옹벽 시공 완료후, 발생된 옹벽 상부의 균열 및 침하와 옹벽 전면의 우수 유출에 대한 문제점을 발견하고 기존 안정성 검토의 결과를 재검토하고자 하였다. 기존 설계단계에서 붕적층에 대한 명확한 검토가 이루어지지 않아 지하수 유출로 인한 문제임을 확인하였으며, 이에 지하수위 조건을 보수적으로 반영하고자 옹벽 최상부에 지하수위선을 위치시켜 사면에 대한 안정성검토를 수행하였다. 검토결과, 우기시 안전율은 1.31로 기준안전율 1.3을 상회하는 결과를 확인하였으나, 지진시 안전율이 1.12로 기준안전율 1.3을 만족하지 못하는 것으로 확인되었다. 이에 기존 1, 2단 시공된 옹벽은 그라우팅을 이용한 마이크로 파일과 같은 보강공법을 적용하고, 붕적층에 대한 명확한 검토 수행수 추가 공사가 이루어져야할 것으로 사료된다.

Keywords

References

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