Tunnel and Underground Space (터널과지하공간)

Korean Society for Rock Mechanics and Rock Engineering (한국암반공학회)
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An Experimental Study on the Evaluation of Early-Age Mechanical Properties of Polymer-Based Thin Spray-on Liners

폴리머 기반 박층 라이너의 초기재령 특성 평가를 위한 실험적 연구

  • 장수호 (한국건설기술연구원 GEO-인프라 연구실) ;
  • 이규필 (한국건설기술연구원 GEO-인프라 연구실) ;
  • 한진태 (한국건설기술연구원 GEO-인프라 연구실) ;
  • 박영택 (한국건설기술연구원) ;
  • 최순욱 (한국건설기술연구원 GEO-인프라 연구실) ;
  • 황귀성 (실크로드티앤디 연구개발팀) ;
  • 최명식 (실크로드티앤디)
  • Received : 2013.10.10
  • Accepted : 2013.10.23
  • Published : 2013.10.31
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Abstract

Thin Spray-on Liners(TSLs) based on polymer materials have been considered as an alternative to shotcrete and wire mesh in relatively fair rock conditions, and used in mines since 1990s. Nevertheless, Few experimental studies on their mechanical properties necessary for the evaluation of their bearing capacities as a support member have been carried out. In this study, tensile and bond strengths of two kinds of TSLs with different material compositions were measured at the age of 7 days. In addition, two kinds of bending tests proposed by EFNARC (2008) to simulate representative failure mechanisms of TSLs were carried out on the same materials and curing age as in tension and pull-out tests. From the tests, tensile strength of a TSL is shown to increase as its content of polymer is higher. In contrast, its bond strength seems to be in inverse proportion to its polymer content. Especially, the TSL material in which a cementitious component is included with relatively smaller polymer content shows a faster hardening characteristic which results in higher resistance to de-bonding between a TSL and a substrate. As a result, it is shown that the performance of TSLs might be dependent upon its corresponding polymer content.

폴리머 계열의 박층 라이너는 양호한 암반 조건에서 숏크리트와 철망을 대체할 수 있는 새로운 지보재로 고려되고 있으며, 1990년대부터 광산의 안정성 확보를 위해 사용되고 있다. 하지만 TSL의 지보 성능을 평가하기 위한 TSL의 특성에 대한 실험적 연구가 부족한 실정이다. 본 연구에서는 구성 성분이 다른 두 가지 TSL 재료에 대해 재령 7일에 인장강도와 부착강도를 측정하였고, EFNARC(2008)에서 제시하고 있는 지지력 평가 시험도 함께 실시하였다. 시험결과, 폴리머 함량이 높아질수록 재료의 인장강도는 높아지나 상대적으로 부착강도는 작아지는 것으로 나타났다. 특히, 폴리머 함량은 상대적으로 작지만 시멘트계 성분이 포함된 TSL 재료의 경우에는 경화가 빠르기 때문에 부착파괴에 대한 저항성이 높게 나타났다. 이상과 같이 폴리머 함량에 따라 TSL의 성능이 상이하게 나타남을 확인할 수 있었다.

Keywords

References

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