폐기물 매립시설 점토 차수층의 지반 ·환경공학적 특성

Abstract

본 연구는 폐기물 매립시설 점토 - bentonite 혼합 차수층에 대한 지반·환경공학적 특성에 관한 연구이다. 차수층의 투수계수에 영향을 미치는 요소는 bentonite 의 혼합비, 다짐함수비, 투과수 등이 있으며, 실내시험에서 차수재로써 기준을 만족하는 bentonite 의 혼합비를 산정한 후 이 결과를 현장에 적용하였다. 시공이 완료된 각 다짐층에서 현장밀도시험을 실시하여 다짐도를 평가하였으며, 불교란 시료(UD samples)를 채취하여 실내에서 투수시험과 표준 압밀시험(standard consolidation test)을 실시하여 투수계수를 각각 비교하였다.

지정폐기물 매립지의 침출수는 다량의 중금속을 함유하고 있으므로 환경적인 측면에서도 고려해야할 부분이 많다. 침출수는 투수시험에 사용되는 증류수나 수돗물에 비해 비중이 크므로 실제와 비슷힌 CaCl₂2H₂O수용액을 투과수로 사용하여 투수시험을 실시하고, 일반적인 투수계수와 비교하였다. 또한 차수층에 대한 중금속의 흡착능 시험을 실시하고, 여러 등은 흡착식에 대한 비교를 실시하였다.

This study focuses on the geo·environmental characteristics of the bentonite and clay mixtures which have been used as waste containment system clay liners. In the numerous laboratory experiments, the main factors affecting the hydraulic conductivity were bentonite-clay content, compaction water content, and permeant liquids. Permeability tests were performed on the bentonite-clay samples and the freshwater was used as the permeant liquid. Then, the laboratory results were applied to the field work. The compacted clay density by the sand cone method was used as a suitability for a field application. For permeability tests the laboratory permeability and the standard consolidation tests of UD samples were performed.

Adsorption capacity tests for heavy metals were performed and applied to various adsorption isotherm equations.

This study focuses on the geo·environmental characteristics of the bentonite and clay mixtures which have been used as waste containment system clay liners. In the numerous laboratory experiments, the main factors affecting the hydraulic conductivity were bentonite-clay content, compaction water content, and permeant liquids. Permeability tests were performed on the bentonite-clay samples and the freshwater was used as the permeant liquid. Then, the laboratory results were applied to the field work. The compacted clay density by the sand cone method was used as a suitability for a field application. For permeability tests the laboratory permeability and the standard consolidation tests of UD samples were performed.

Adsorption capacity tests for heavy metals were performed and applied to various adsorption isotherm equations.