A Study on Measuring the Coefficient of Earth Pressure at Rest II

J. Ocean Eng. Technol. 2004;18(6):58-69.

SONG MU-HYO;

Division of Civil and Urban Engineering, Dong Eui University;

정지토압계수 측정에 관한 연구 II

송무효;

동의대학교 토목 도시공학부;

Keywords: Lateral Earth Pressure at Rest, Loading/Unloading Condition, Mnulti-Cyclic Models, Ko-Oedometer Apparatus, Relative Density

핵심용어: 정지토압계수, 재하/제하 조건, 다주기 시험, 1차원 압축시험기

Abstract

In order to investigate the characteristics of the lateral earth pressure at rest, under hysteretic $K_o-loading/unloading$ conditions, seven types of multi-cyclic models have been studied, using dry sand. For this study, the new type of $K_o-oedometer$ apparatus was developed, and the horizontal pressure was accurately measured. The multi-cyclic models consist of primarily 3 cases: (i) $K_o-test$ under the same loading / unloading condition, (ii) multi-cyclic loading / unloading $K_o-test$ exceeding the maximum pre-vertical stress, and (iii) multi-cyclic loading / unloading $K_o-test$ within the maximum pre-vertical stress.
Results
fromthe multi-cyclic model indicated that a single-cyclic model could be extended if the exponents for the unloading condition $(alpha;and;alpha^*)$ and the reloading coefficients $(m_r,;and;m_r^{ast})$ were primarily dependent upon the type of model, number of cycles, and the relative density.