AIR PRESSURE DISTRIBUTION INDUCED BY RAINFALL INFILTRATION IN SOIL/WATER/AIR COUPLED SIMULATION

Abstract

Recently, the frequency of torrential rainfall has increased due to global climate change, and
these events cause sediment potential failure. It is difficult to predict when and where a slope failure will
occur because of the concentration of heavy rain. Knowing precursory phenomena, however, is effective for
disaster reduction. Nonetheless, some of these phenomena have not been explained in the framework of
geotechnical engineering. Organic smells and strange sounds, known as precursory signs of slope failure,
propagate through the atmosphere. Therefore, it is important to monitor air movement within earth structures.
This study focuses on pore air behavior within the ground due to rainfall infiltration. Here, the infiltration
column test combined with monitoring smell, as conducted by Tsuchida et al., was first simulated using the
soil/water/air coupled finite element code, DACSAR-MP. Next, a sloping earth structure exposed to rainfall
was simulated. Consequently, it was found that distribution of pore air pressure was dependent on drainage
conditions of air, and that pore air behavior influenced rainfall infiltration behavior.