Strength Characteristics of Reinforced Lightweight Soils for Recycling Dredged Soils

摘要

In order to reuse dredged soil as a construction material, the reinforced lightweight soil using geogrid was developed. The lightweight soil which was consisted of dredged clayey soil, cement and air-foam, was reinforced with geogrid in order to increase its compressive strength. This paper investigates strength characteristics and stress-strain behaviors of the geogrid-reinforced lightweight soil. Test specimens were prepared on various mixing conditions including cement content, initial water content, air-foam content and geogrid layer and then several series of unconfined compression tests were carried out. From the experimental results, it was found that unconfined compressive strengths as well as stress-strain behaviors of lightweight soil were strongly influenced by mixing conditions. The more cement content that is added to the mixture, the greater its unconfined compressive strength. However, the more initial water content or the more air-foam content, the less its unconfined compressive strength. It was observed that the compressive strength of reinforced lightweight soil was increased due to the reinforcing effect by the geogrid for most cases. Stress-strain relation of geogrid-reinforced lightweight soil showed a ductile behavior rather than a brittle behavior. In reinforced lightweight soil, secant modulus (E(50)) was also increased as its compressive strength increased due to the inclusion of geogrid.