Journal of the Korean Geosynthetics Society (한국지반신소재학회논문집)

Korean Geosynthetics Society (한국지반신소재학회)
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Evaluation of Creep Reduction Factor for Geosynthetic Strip Reinforcement with Folding Grooves

접힘홈이 형성된 띠형 섬유보강재의 크리프 감소계수 평가

  • Lee, Kwang-Wu (Department of Infrastructure Safety Research, Korea Institute of Civil engineering and building Technology) ;
  • Cho, Sam-Deok (Department of Infrastructure Safety Research, Korea Institute of Civil engineering and building Technology)
  • Received : 2018.11.21
  • Accepted : 2018.12.17
  • Published : 2018.12.30
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Abstract

In this study, a series of accelerated creep tests (SIM) was carried out on geosynthetic strip reinforcements with folding grooves having different tensile strengths (15 kN, 25 kN, 35 kN, 50 kN, 70 kN, and 90 kN) to analyze creep characteristics and to assess creep reduction factors. In particular, long-term creep tests were conducted on geosynthetic strip reinforcements with 25 kN tensile strength, which is widely used, to compare and analyze the accelerated creep test results. As a result, the creep reduction factor increased with an increasing design life of reinforcement. In addition, geosynthetic strip reinforcement using the same material and manufacturing method showed similar creep reduction factors at the same design life for different tensile strengths. When both long-term and accelerated creep test data were used, the creep reduction factors from the accelerated test were estimated to be 5.9%~7.1% less than those from the long-term creep test for the design life ranging from 50 to 100 years.

본 연구에서는 접힘홈이 형성된 띠형 섬유보강재를 대상으로, 보강재 종류 및 크리프시험 방법에 따른 크리프특성을 분석하고 크리프 감소계수를 평가하기 위하여 인장강도가 다른 6종류의 띠형 섬유보강재(인장강도 15kN, 25kN, 35kN, 50kN, 70kN, 90kN)에 대한 가속 크리프시험(SIM)을 수행하였다. 또한, 특히 활용 빈도가 높은 인장강도 25kN인 띠형 섬유보강재에 대해서는 장기 크리프시험을 동시에 수행하여 가속 크리프시험 결과와 비교, 분석하였다. 분석 결과, 보강재의 설계수명이 증가할수록 크리프 감소계수가 증가하고, 동일한 소재와 제조방법을 사용한 띠형 섬유보강재는 인장강도가 서로 다르더라도 설계수명에 따라 거의 유사한 크리프 감소계수값을 보여주며, 장기 및 가속 크리프시험 데이터를 모두 사용한 경우의 크리프 감소계수는 장기 크리프시험 데이터만 사용한 경우보다 설계수명 50년~100년을 고려하면 크리프 감소계수가 5.9%~7.1% 정도 작게 평가됨을 알 수 있었다.

Keywords

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Fig. 1. Evaluation process of creep characteristics using Stepped Isothermal Method (SIM)

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Fig. 2. Geosynthetic strip reinforcement used for creep tests

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Fig. 3. Conventional long-term creep test equipments

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Fig. 4. Accelerated creep test equipment

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Fig. 5. Creep behavior over time of geosynthetic strip reinforcements

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Fig. 6. Conventional long-term creep test results

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Fig. 7. Creep rupture curves of 6 geosynthetic strip reinforcements (SIM)

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Fig. 8. Creep rupture curve of FL 25 kN reinforcement including both long term and accelerated creep test results

Table 1. Comparison of creep test methods for geosynthetic reinforcement

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Table 2. Engineering properties of geosynthetic strip reinforcements used for creep tests

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Table 3. Load and temperature conditions applied to creep test

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Table 4. Creep characteristic value range according to creep load of six reinforcements (SIM)

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Table 5. Creep characteristic value according to creep load of FL 25kN reinforcement (CCT)

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Table 6. Creep characteristic value according to creep load of FL 25kN reinforcement (CCT)

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Table 7. Differences in creep reduction factors by long-term and accelerated creep tests (2,000 and 10,000 hours, FL 25kN)

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Table 8. Creep reduction factors of FL 25kN reinforcement according to the design life

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