CHANGES IN PHYSICAL PROPERTIES AND CAUSES OF DEFORMATION OF EMBANKMENT USING FRAGILE ROCK SLAG AFTER START OF SERVICES

Abstract

 In the Green Tuff region at Tohoku district, many embankments have been constructed fragile rocks from taken the near site. The embankment has been constructed to tightly compact so that the air porosity is less than 15%. However, in recent years, the fragile rock embankment has been deformed and collapsed due to aged deterioration, which is a problem at the site of maintaining and managing expressways. In this paper, we investigated the physical property change of the valley filling embankment in which cracks intermittently occurred on the pavement surface after several years of service start, and considered the causal relationship between changes in physical property of the embankments and their deformation. As a result, it was found that the slaking rock slag was considered to have been refined from the initial stage of the service. In addition, fine particles moved downward during the infiltration and discharge of rainwater, and loosening and hollowing occurred at the upper shoulder. In addition, it was found that the groundwater level into the embankment was raised by making the finely divided soil into a clay below the embankment, which resulted in instability of the embankment slope. In addition, the change in water permeability due to the actually adjusted particle size distribution was also evaluated.