Abstract: Geohazard occurrence frequency increases with the social economic development and engineering activities. Geohazards could seriously affect the properties, human safety as well as social sustainable development. This paper presents the 1:50,000 scale geological investigation results of 54 piping locations in Nanxian and Ziyang, Yiyang City. Soil samples were collected from the two piping locations with each at Nanxian and Ziyang and laboratory tested. It is concluded that the piping preventive measures should be within 15H away from the toe for levees in Dongting area. These investigation results can provide information in minimizing the piping hazards in Dongting area.

Key words: piping, seepage layer, mitigation zone, remediation