단지 조성을 위한 과압밀점토의 설계침하량에 대한 고찰

Study on the Design Settlement of Over-Consolidated Clay for a Complex Development

본 연구는 과압밀상태가 발달된 서해안의 압밀침하특성을 파악하고 현장시험과 설계정수 재평가를 통해 기존 압밀설계의문제점을 파악하고자 하였다. 기존의 설계방법으로 설계시 침하비(계측 침하량/설계 침하량)가 56.0%로 산정이 되었으나, 본 연구에서 제시한 선행압밀응력과 압축지수 재평가를 통한 침하비는 95.6~96.6%로 나타나 과압밀상태가 발달된 서해안지역에 적용 가능한 것으로 나타났다. 또한 서해안 지반과 같이 저소성 실트 지반의 압밀시험곡선은 전반적으로 변곡점이명확하지 않는 둥근 곡선(rounded curve)을 나타내므로 Casagrande 방법 적용시 선행압밀압력을 결정하기 어려우며 과소평가되는경향이 나타났으며, Schmertmann의 보정압축지수를 적용하는 것 보다는 압밀곡선에서 얻어진 압축지수를 그대로 적용하는것이 바람직한 것으로 분석 되었다.

The purpose of this study was to understand the consolidation settlement characteristics of the west coast, where overconsolidation has occurred, and to identify the problems of existing consolidation design through field tests and the re-evaluation of design parameters. The settlement ratio (measurement settlement/design settlement) obtained using the existing design method was calculated to be 56.0%; however, the settlement ratio obtained through the re-evaluation of the preconsolidation stress and compression index suggested in this study was 95.6-96.6%. It was applicable to the west coast region, where the condition of overconsolidation developed. In addition, the consolidation test curve of the low-plasticity silt ground in the west coast region showed a rounded curve with no clear inflection point. It was difficult to determine the preconsolidation stress when applying the Casagrande method, and it tended to be underestimated. Analysis showed that it is preferable to apply the compression index obtained from the compaction curve as it is, rather than to apply Schmertmann s modified compression index.