변곡점을 이용한 신속한 압밀시험에 관한 연구

Abstract

일반적으로 점성토의 압밀계수는 하중단계마다 일차압밀이 100% 완료되기까지 충분한 재하시간(24h)을 필요로 하는 표준압밀시험을 통해서 구할 수 있다. 하지만, 표준압밀시험으로는 간극수압을 직접 측정하기가 어렵고, 압밀완료시간이 최소한 1주일 이상이 소요된다. 따라서, 신뢰성 있는 값을 확보하면서 신속한 압밀시험 방법의 개발이 요구된다.

본 연구에서는 Inflection Point Method(Francis R. Cour 1971)[2]를 이용하여 신속히 압밀계수를 구하는 Rapid Inflection Point Method에 대한 연구를 수행하였다. 본 연구의 결과로 얻어진 압밀계수는 Taylor방법, Casagrande방법, Rectangular Hyperbolar방법으로 구한 압밀계수와 비교하였고[1], Rapid Rectangular Hyperbolar(A. Sridharan 등, 1999)방법[8]으로 구한 압밀계수와 비교·분석하여 그 적용성을 검토하였다. 또한, 본 연구를 통해서 압밀시간 단축에 관한 타당성을 입증하였다.

This study presented the new method for evaluating the coefficient of consolidation by using inflection point method which was based on the fact that time factor, T corresponding to the inflection point of a semilogarithmic plot of a time curve is fixed and equals to T = 0.405 at 70% consolidation. In the proposed method, the next load increment is applied as soon as the necessary time reqaired to identify the inflection point. Thus, the coefficient of consolidation may be easily evaluated. The time required to complete the testing using this rapid consolidation method could be as low as 1∼5 hours compared with 1 or 2 weeks in the case of the conventional consolidation test.

Keyword : consolidation, inflection point, rapid consolidation method

This study presented the new method for evaluating the coefficient of consolidation by using inflection point method which was based on the fact that time factor, T corresponding to the inflection point of a semilogarithmic plot of a time curve is fixed and equals to T = 0.405 at 70% consolidation. In the proposed method, the next load increment is applied as soon as the necessary time reqaired to identify the inflection point. Thus, the coefficient of consolidation may be easily evaluated. The time required to complete the testing using this rapid consolidation method could be as low as 1∼5 hours compared with 1 or 2 weeks in the case of the conventional consolidation test.

Keyword : consolidation, inflection point, rapid consolidation method