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2014 Vol.30, Issue 5 Preview Page
Stress-Strain Characteristics of Weathered Granite Soil in Plane Strain Test

평면변형시험을 이용한 화강풍화토의 응력-변형률 특성

You-Seong Kim1
,
Jin-Kwang Lee2
,
Jae-Hong Kim3*
김 유성1
,
이 진광2
,
김 재홍3*
1Prof., Dept. of Civil Engrg., Chonbuk National Univ.
2Graduate Student, Dept. of Civil Engrg., Chonbuk National Univ.
3Research Prof., Dept. of Civil Engrg., Chonbuk National Univ.
1전북대학교 토목공학과 교수
2전북대학교 토목공학과 석사과정
3전북대학교 토목공학과 연구교수
*교신저자. *Corresponding Author. 
31 May 2014. pp. 37-46
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Abstract

Geotechnical structures have been analyzed and constructed in various geometry conditions to maintain their stability in accordance with the characteristics of construction design. Shear strengths are generally obtained from triaxial test to apply to design analysis. Geotechnical structures under strip loading, such as earth dam, embankment, and retaining wall, have the strain in a direction, and plane strain condition. Thus, an approximate shear strengths should be applied for stability analysis suitable to ground condition. When applying shear strengths obtained from triaxial tests for slope stability analysis, the evaluation of it may underestimate the factor of safety because the implementation is not suitable for geometry condition. The paper compares shear strengths obtained from triaxial test and plane strain test based on various relative densities using weathered granite soils. Additionally, yield stress is determined by maximum axial strain 15% in triaxial test because of continuous kinematic hardening, but plane strain test can determine a failure point in critical state to evaluate the shear strengths of soils at the second plastic hardening step. This study proposes to perform an appropriate test for many geotechnical problems with plane strain condition.

Keywords
Geotechnical structure
Triaxial test
Plane strain test
Shear strength
Hardening behavior

다양한 지반조건을 갖고 있는 지반구조물들은 공사 설계에 대한 특성에 따라 안정성 해석을 하여 설계와 시공이 되어야 한다. 일반적으로 지반의 강도정수들은 삼축압축시험으로 분석한 결과를 설계시공에 적용하여 안정성을 해석한다. 띠하중과 같은 응력을 받고 있는 댐, 제방, 옹벽 등은 한방향의 변형이 구속되어 있는 평면변형 조건의 지반구조물들이다. 지반 조건에 맞는 안정성 해석은 적절한 강도정수들의 적용에 의해서 이루어져야 한다. 삼축압축시험에 의한 강도정수 적용은 이러한 지반구조물들을 설계할 때, 안전율이 과소평가되어 시공성과 경제성에 불리하게 작용한다. 본 연구는 화강풍화토를 대상으로 삼축압축시험과 평면변형시험을 통하여 강도정수를 산정하고 상대밀도에 따른 강도 증가에 대한 경향을 분석하고자 한다. 삼축압축시험은 응력경화가 지속적으로 발생하기 때문에 최대 변형률 15%에서 한계파괴응력을 결정짓는 반면에, 평면변형 조건에서 수행되는 시험은 강도가 증가하면서 2번의 뚜렷한 응력경화를 나타내었고, 강도정수를 결정할 수 있는 항복응력을 구분할 수 있었다.

References
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2
2.Budhu, M. (2011), Soil Mechanics and Foundations, 3rd edition, JOHN WILEY & SONS, INC., pp.141-143.
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11
Received : December 18th, 2013
12
Revised  : March 5th, 2014
13
Accepted : April 3rd, 2014
Information
  • Publisher :The Korean Geotechnical Society
  • Publisher(Ko) :한국지반공학회
  • Journal Title :Journal of the Korean Geotechnical Society
  • Journal Title(Ko) :한국지반공학회 논문집
  • Volume : 30
  • No :5
  • Pages :37-46
  • Received Date : 2013-12-18
  • Revised Date : 2014-03-05
  • Accepted Date : 2014-04-03
  • DOI :https://doi.org/10.7843/kgs.2014.30.5.37
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