Journal of the Korean GEO-environmental Society (한국지반환경공학회 논문집)

Korean Geo-Environmental Society (한국지반환경공학회)
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Estimation of Consolidation Characteristics of Soft Ground in Major River Mouth

주요 강하구 연약지반의 압밀 특성 평가

  • Lee, JunDae (Department of Civil Engineering, Semyung University) ;
  • Kwon, YoungChul (Department of Civil Engineering and Management, Tohoku Institute of Technology) ;
  • Bae, WooSeok (R&D Center, NANO-GEO ENC Co. Ltd.)
  • Received : 2018.12.04
  • Accepted : 2019.01.31
  • Published : 2019.02.01
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Abstract

The coastal area forms various sedimentary layers according to the environmental conditions such as the topography and geological features of the upper region of the river, ocean currents, and river mouth. Therefore, identifying the characteristics of the marine clay deposited in the coastal area plays a key role in the investigation of the formation of soft ground. In general, alluvial grounds are formed by a variety of factors such as changes in topography and natural environment, they have very diverse qualities depending on the deposited region or sedimentation conditions. The most important thing for the construction of social infrastructures in soft ground areas is economical and efficient treatment of soft ground. In this study, the author collected data from diverse laboratory and field tests on five areas in western and southern offshore with relatively high reliability, and then statistically analyzed them, thereby presenting standard constants for construction design. Correlation between design parameters such as over consolidation ratio, preconsolidation pressure was analyzed using linear and non-linear regression analyses. Also, proposed distribution characteristics of design parameters in consideration of each region's uncertainty through statistical analyses such as normality verification, outlier removal.

해안지역은 강의 지형과 지질, 해류 및 강하구 등 환경조건에 따라 다양한 퇴적층을 구성하므로 해안지역에 충적된 해성점토 특성을 파악하는 것이 연약지반의 형성을 규명하는데 중요한 역할을 수행하게 된다. 일반적으로 충적지반은 지형과 자연환경변화와 같은 다양한 구성요소로 형성되므로 퇴적된 지역이나 퇴적상황에 따라 매우 다른 성질을 가지게 된다. 더구나 해안지역을 따라 다양한 대형사업이 강하구에 집중됨으로써 해류의 흐름이나 퇴적특성이 바뀌어 퇴적상태가 변하여 불확실성이 더욱 심해지고 있는 상황이다. 따라서 본 연구에서는 지반의 불확실성을 고려한 설계 상수를 제시할 목적으로 서해안과 남해안을 5개 영역으로 구분하고 대상연안에 해당되는 상대적으로 높은 신뢰성을 가진 실내 및 현장조사 자료를 수집하여 통계적인 분석을 수행하였으며, 선형 및 비선형 회귀 분석을 사용하여 설계 매개 변수 간의 상관관계를 분석하였다. 또한 정상 검증, 이상치제거와 같은 통계 분석을 통해 각 지역의 불확실성을 고려한 설계 매개 변수의 분포 특성을 제안했다.

Keywords

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Fig. 1. Variation of activities with river site

HJHGC7_2019_v20n2_69_f0002.png 이미지

Fig. 2. Variation of preconsolidation pressure with depth

HJHGC7_2019_v20n2_69_f0003.png 이미지

Fig. 3. Variation of the OCR with depth

HJHGC7_2019_v20n2_69_f0004.png 이미지

Fig. 4. Relationship between Pc and depth

Table 1. Maximum data of major river mouth

HJHGC7_2019_v20n2_69_t0001.png 이미지

Table 2. Comparison of physical properties

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Table 3. Descriptive statistics of original data

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Table 4. Results of normality tests using Kolmogorov-Smirnov

HJHGC7_2019_v20n2_69_t0004.png 이미지

Table 5. Descriptive statistics with outlier filtering

HJHGC7_2019_v20n2_69_t0005.png 이미지

Table 6. Results of Linear regression analysis about D-Pc

HJHGC7_2019_v20n2_69_t0006.png 이미지

Table 7. Results of statistical analysis about Pc/[qu/2] after O.F

HJHGC7_2019_v20n2_69_t0007.png 이미지

Table 8. Results of statistical analysis about OCR

HJHGC7_2019_v20n2_69_t0008.png 이미지

Table 9. Comparison of design factors

HJHGC7_2019_v20n2_69_t0009.png 이미지

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