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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

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.

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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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References

  1. ASTM (2007) Standard Test Method for Evaluating the Unconfined Tension Creep and Creep Rupture Behavior of Geosynthetics (ASTM D5262)., American Society for Testing and Materials.
  2. Berg, R. R., Christopher, B. R. and Samtani, N. C. (2009), Design and Construction of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes - Volume 1, Publication No. FHWA-NHI-10-024, U.S. DOT FHWA, 306 p.
  3. Cha, D. H., Yoon, K. J., Koo, H. J. and Jeon, H. Y. (2008), "Estimation of creep reduction factor from creep behavior of geogrid", Proc. of the Spring 2008 Geosynthetics Conference, Vol.1, April 18, Seoul, pp.105-113.
  4. Cho, S. D., Oh, S. Y., Lee, K. W. and Lee, D. H. (2004)., "Assessments of Installation Damage and Creep Deformation of Geogrids", Journal of Korean Geosynthetics Society, Vol. 3, No.4, pp.29-40.
  5. Cho, S. D. (2018), "Technical development status of reinforced earth wall in Korea", Proc. of the KGS Spring National Conference 2018, Vol.1, March, 14-16, Yeosu, pp.1-13.
  6. Han, J. G., Yoon, W. I., Hong, K. K., Lee, K. W. and Cho, S. D. (2011), "Pullout behavior using strain distribution of geosynthetic strip", Proc. of the Spring 2011 Geosynthetics Conference, Vol.1, April 22, Seoul, pp.89-96.
  7. Hong, K. K. (2011), Evaluation of pullout resistance and design of strip-type reinforcement based on anchorage effect, Doctoral Dissertation, Graduate School, Chung-Ang University, Seoul. 257 p.
  8. ISO (2007). Guidelines for the determination of the long-term strength of geosynthetics for soil reinforcement (ISO TR 20432)., International Organization for Standardization.
  9. Jeon, H. Y., Mok, M. S., Chang, Y. C. and Cho, S. H. (2001), "Analysis of creep behaviors of geosynthetics", Proc. of the 2001 Geosynthetics Conference, Vol.1, Nov. 30, pp.43-55.
  10. Jeon, H. Y., Yoo, J. C. and Byun, S. W. (2002), "Assessments of long-term performance of geosynthetics by creep factors", Proc. of the Fall 2002 Geosynthetics Conference, Vol.1, Nov. 27, pp.199-208.
  11. Jeon, H. Y., Ryu, J. J., Kim, H. T., Kim, K. M. and Kim, Y. Y. (2003), "Assessment of creep properties of strip type fiber reinforcement", Journal of Korean Geotechnical Society, Vol.19, No.2, pp.279-289.
  12. Jeon, H. Y. and Mok, M. S. (2007), "Suggestion for Interpretation of Limit Creep Strain of Geogrids", Journal of Korean Geosynthetics Society, Vol.6, No.4, pp.1-6.
  13. Jung, S. G., Lee, K. W., Kim, J. H., Cho, S. D., Koo, H. J. and Cho, H. W. (2012), "Evaluation of tensile creep deformation of geosynthetic strips used for reinforcement", Proc. of the Fall 2012 Geosynthetics Conference, Vol.1, Nov. 9, Seoul, pp.47-50.
  14. Jung, S. G., Lee, K. W., Kim, J. H., Cho, S. D., Koo, H. J. and Cho, H. W. (2013), "A case study on evaluation of creep reduction factor for geosynthetic strip reinforcement", Proc. of the Fall 2013 Geosynthetics Conference, Vol.1, Nov. 15, Seoul, pp.61-64.
  15. Koo, H. J., Kim, D. W., Kim, Y. K. and Jeon, H. Y. (2004), "Accelerated Creep Testing of Geogrids: Time-Temperature Superposition and Statistical Data Analyses", Journal of Korean Geosynthetics Society, Vol.3, No.3, pp.33-40.
  16. KS (2007a), Geosynthetics : Wide-width tensile test (KS K ISO 10319)., Korean Agency for Technolgy and Standars.
  17. KS (2007b), Geotextiles and geotextile-related products : Determination of tensile creep and creep rupture behaviour (KS K ISO 13431)., Korean Agency for Technolgy and Standars.
  18. Lee, K. W., Kim, J. H., Cho, S. D., Han, J. G., Yoon, W. I. and Hong, K. K. (2010), "Experimental study on long-term performance evaluation of geosynthetic strip reinforcement", Journal of Korean Geosynthetics Society, Vol.9, No.4, pp. 75-84.