침하 저감용 보강재로 보강된 인공어초 설치 지반의 거동 특성

Behaviors of Artificial Reef Reinforced with Settlement Reduction Reinforcement

Abstract

본 연구에서는 인공어초의 침하 및 세굴을 저감하고자 다양한 보강재로 보강된 해저 지반의 침하 및 세굴 거동 특성을 알아보았다. 지반에 적용한 보강재는 총 3가지로서 지오그리드(geogrid), 지오그리드-대나무 매트(geogrid-bamboo mat, GBM) 및 해초-지지봉 매트(seaweed-pile mat, SPM)를 각각 보강하여 실험을 수행하였다. 모래, 실트 및 점토 지반에 대해 지지력 실험, 대형 수조 침하 실험, 2차원 흐름 수조 세굴 실험 등 다양한 실내 실험을 수행하였다. 실험 결과 보강재의 보강에 따라 인공어초의 지지력 증진, 침하 및 세굴이 저감되는 효과를 보였으며, 모래나 실트 지반보다 점토 지반과 같은 연약 지반에서 보강효과가 더 크게 나타나는 경향을 보였다.

This study investigated settlement and scouring characteristics of artificial reef reinforced with various reinforcement types to reduce settlement and scouring. Three reinforcement types were prepared: geogrid, geogrid-bamboo mat (GBM) and seaweed-pile mat (SPM). Various laboratory tests such as bearing capacity test, large size settlement test, two-dimensional flow scour test were performed according to different soil types (sand, silt, clay). Laboratory test results indicated that bearing capacity of seabed with a reinforced artificial reef increased and its settlement and scour depth reduced for all reinforcement types. Especially, reinforcement effect tends to be greater in clay soft ground rather than sand and silt grounds.

Fig. 1. Particle size distributions

Fig. 2. Reinforced type

Fig. 3. Bearing capacity test

Fig. 5. Two-dimensional flow scour test

Fig. 4. The large size settlement test

Fig. 6. BIR distribution according to reinforced types and soil types

Fig. 7. Settlement behavior according to soil types

Fig. 8. SRR distribution according to reinforced types

Fig. 9. Relationship between BIR and SRR

Fig. 10. Relationship between bearing capacity and settlement /length of AR

Fig. 11. Scour depth according to soil types

Fig. 12. SDR distribution according to reinforced types

Fig. 13. Relationship between bearing capacity and SDR

Table 1. Geotechnical properties of soils

Table 2. Law of similarity of reinforcement

Table 3. Experimental conditions for the flow test