Experimental Study on the Generation of Odor During Rainwater Infiltration Process

Abstract

Although it is known that the generation of odor is one of the precursory phenomena of landslide disasters, the mechanism by which offensive odors are detected before landslides is not fully clarified. It has been reported that high odor intensity was observed from the pore air in soil at 0-3m depth on natural slopes with a history of landslide disaster history. In this study, laboratory experiments were conducted to examine the possibility of the generation of odors during rainwater infiltration process. We made a model ground mixed with odorants and conducted the following two experiments, 1) measurement of odor intensity on the surface of 10 cm height soil layer when the groundwater level rose by injecting water from the bottom, 2) measurement of odor intensity on the surface during rainwater infiltration process using a 1 m height soil layer and a laboratory rainfall device. From these tests, it was found that there is no or very little increase in odor intensity on the surface in the process that the pore air in soil was released from the surface accompanied by the rainwater infiltration. However, in both tests, the measured odor intensity increased rapidly when the ground water level approached the surface. It can be said that the generation of odor as a precursor phenomenon can be caused when the level of groundwater containing odorants reaches near the ground surface.