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Evaluation of Land Subsidence Risk Depending on Grain Size and Verification using Numerical Analysis

지반입도조건에 따른 지반함몰 가능성 평가 및 수치해석적 검증

  • Lee, Jong-Hyun (Multi Disaster Countermeasures Organization, Korea Institute of Construction and Technology) ;
  • Jin, Hyun-Sik (HNG Consultants Co., Ltd.) ;
  • Baek, Yong (Multi Disaster Countermeasures Organization, Korea Institute of Construction and Technology) ;
  • Yoon, Hyeong-Suk (Depart. of Civil & Environmental Eng., Inha College)
  • 이종현 (한국건설기술연구원 복합재난대응연구단) ;
  • 진현식 ((주)HNG컨설턴트 지반사업부) ;
  • 백용 (한국건설기술연구원 복합재난대응연구단) ;
  • 윤형석 (인하공업전문대학 토목환경과)
  • Received : 2017.05.08
  • Accepted : 2017.06.23
  • Published : 2017.06.30

Abstract

In this study, filter conditions by difference in grading between core material and filter material used for dam construction was applied as evaluation condition for surrounding ground conditions near excavation site in a bid to identify the risk of land subsidence resulting from the erosion of soil particles. To that end, filter conditions proposed for the test was evaluated and the risk of land subsidence depending on grain size conditions was also evaluated using the filter conditions developed by COE. Consequently, evaluation diagram that can be used to determine the risk of land subsidence using grain size conditions obtained from ground investigation data was developed, which is expected to help evaluate the possibility of land subsidence depending on changes to the stratum. To simulate the particle flow process, PFC3D program was used. It's not only intended to determine the land subsidence pattern caused by falling ground water level but also predict and evaluate the land subsidence caused by soil erosion using grain size condition which can be verified by numerical analysis approach.

본 연구에서는 지반함몰의 실질적 원인인 토립자 유실에 의한 함몰 가능성을 판단하기 위해 댐설계 시 활용되고 있는 코어재와 필터재의 입도 차이에 의한 필터조건을 굴착공사 주변의 지반조건에 대한 평가 조건으로 응용하였다. 이를 위해 여러 제안자들이 실험 등을 통해 제안한 필터 기준을 확인하였으며, 이 중 미공병단에서 제안한 필터조건을 이용하여 지반입도 조건에 따른 지반함몰 가능성을 판단해 보았다. 이를 통해 사용자가 지반조사 정보로부터 획득한 지반입도조건을 이용하여 빠르게 지반함몰 가능성을 판단할 수 있는 평가도표를 작성하였으며, 다양한 굴착 주변의 지층 변화에 따른 지반함몰 가능성을 쉽게 평가해 볼 수 있을 것으로 판단된다. 또한, 입자유동 과정을 모사하기 위해 PFC3D 프로그램을 활용하였으며, 이것은 단순 지하수위 저하에 의한 지반침하 경향을 판단하는 것이 아니라 실질적인 토립자 유실에 의한 지반함몰 예측 및 평가가 지반입도조건을 통해 이루어질 수 있고 이를 수치해석 적으로 검증할 수 있음을 나타낸다.

Keywords

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