점토의 이차 압축특성에 관한 연구

Abstract

울산의 '삼산'지역은 유기질을 많이 함유한 점성토가 넓고 두껍게 분포되어 있으며, 이러한 연약지반에 고층 구조물이 축조될 경우, 시간이 경과함에 따라 장기적인 침하가 유발되므로 이차압축을 고려하여야 한다. 본 연구에서는 현장에서 채취한 불교란시료에 대하여 실내 표준압밀시험을 수행하고, 그 결과를 이용하여 포화된 '삼산'지역 연약점토의 이차압축특성을 밝혔다.

분석 결과, 자연함수비와 이차압축의 관계는 Mesri의 선보다 상부에 분포하여 이차압축의 영향이 큰 것으로 나타났으며, 정규압밀점토의 침하거동을 하는 것으로 나타났다. 이차 암축지수, Ca와 일차압축지수, Cc 관계는 Ca=0.049Cc + 0.0017의 선형관계식으로 표현할 수 있으며, Cr/Cc가 0.1-0.2의 범위에 있어 팽창성이 큰 예민점토로 나타났다. 따라서, '삼산'지역 퇴적점토의 침하문제를 취급할 경우 이차압축의 영향을 반드시 고려하여야 할 것으로 판단된다.

The organic clay is widely and thickly deposited at 'Samsan', Ulsan. Usually the soft soils are settled continuously due to self-weight during a long period. The long-term settlement depending on the time has to consider teh effect of secondary compression. In this research, the secondary compression characteristics of the soft clay has been analysed from the results of standard consolidation tests with the undisturbed samples.

The test results of the 'Samsan' clay has been plotted at the upper part in teh Mesri's chart so the effect of secondary compression could not be ignored. The secondary compression index, Ca has been increased linearly with the compression index, Cc; Ca = 0.049 cc + 0.0017. And the ratio of the swell index and the compression index, Cr/Cc has been ranged from 0.1 to 0.2. Consequently, for prediction of the settlement in 'Samsan', the effect of secondary compression has to be considered.

The organic clay is widely and thickly deposited at 'Samsan', Ulsan. Usually the soft soils are settled continuously due to self-weight during a long period. The long-term settlement depending on the time has to consider teh effect of secondary compression. In this research, the secondary compression characteristics of the soft clay has been analysed from the results of standard consolidation tests with the undisturbed samples.

The test results of the 'Samsan' clay has been plotted at the upper part in teh Mesri's chart so the effect of secondary compression could not be ignored. The secondary compression index, Ca has been increased linearly with the compression index, Cc; Ca = 0.049 cc + 0.0017. And the ratio of the swell index and the compression index, Cr/Cc has been ranged from 0.1 to 0.2. Consequently, for prediction of the settlement in 'Samsan', the effect of secondary compression has to be considered.