Rayleigh Wave Velocity for Frost Susceptible Volcanic Ash Deposits in Asama Volcano

摘要

In the regions covered with pyroclastic fall deposits, most of the frost-heave damages of road relates to hydrogeological conditions of a location. In this study, emphasis is given to the effect of soil stratification on the frost damages of road. As a geological exploration Rayleigh wave method was employed for the ashy deposits in the foot of Asama volcano. The frost damages attributed to geological conditions can be summarized as following two forms: (1) Frost damages dominated by the thickly covered, high-heaving soils, (2) Frost damages dominated by drainage conditions of roadbed formed by low-heaving soils. The low-heaving soils easily become mid-heaving soils if once groudwater flows into the soils.