국내 초연약지반의 비배수전단강도 특성 및 개량표준관입시험기 개발

In this study, SPT, FV, and CPT tests were performed at five very soft grounds in southern coast of Korea to characterize the S u of very soft ground. In addition, a new modified SPT that is applicable to very soft ground was developed. Tests results showed that in very soft ground (N＜2), the Su was lower than 12.5 ㎪ using the empirical N-Su correlation, and lower than 50 ㎪ and 65 ㎪ using vane shear test and CPT, respectively. It was shown that the results of in-situ tests were higher than those estimated from the N-Su correlation, and it was also demonstrated that the range of estimated Su was quite wide. New correlations that relate the modified SPT N m with Su from FV and CPT were developed, which are S u =1.76N m -10.47 and S u =1.82N m -9.71, respectively.