An outdoor earth-tank experiment on the identification of factors behind the deformation of reinforced earth walls made using geotextile materials and related preventive measures

An increasing number of applications are being found for reinforced earth walls made using geotextile materials, which enable the effective use of surplus soil and the construction of steep slopes on road embankments and in other land development work. While the deformation of such walls due to frost heaving has been reported in cold regions, few studies have addressed countermeasures for the phenomenon. Accordingly, full-size models were created in an outdoor earth-tank, and strain/deformation were monitored over a period of three years to obtain measurements of the reinforced walls deformed in freezing conditions. Simultaneously, measures focusing on replacement, drainage and heat insulation were implemented to control deformation caused by frost heave, and were compared with the standard method. As the data obtained confirmed that the heat insulation measure had some effect, it was used in frost-heave control work around existing reinforced earth walls to prevent freezing. Full-size reinforced earth walls were also constructed on the ground with a focus on the heat insulation method, and the results were compared with those of the standard method. The outcome showed that strain and deformation caused by frost heave continued after thawing, and worsened when freezing occurred the following winter. In contrast, the replacement method proved to be the most effective approach for controlling frost heave-related deformation of reinforced earth walls made using geotextile materials. It was also revealed that the technique was effective for controlling frost heave in existing reinforced earth walls with the installation of insulating materials.