ABSTRACT
This chapter discusses a three-dimensional seepage flow analysis considering cracks for OODAIRA Landslide reactivated during melting snow period and verified availability of a three-dimensional seepage flow analysis reflecting hydro-geological structure with aspect cracks. Stratum water and crack water through cracks of bedding planes and of joint surfaces give a great influence on the amount of displacement of moving mass in a landslide area. Groundwater consists of stratum water and crack water. The hydro-geological structure where groundwater flows in crack zones and stratums affects landslide displacement. The chapter examines the three-dimensional modeling of seepage flow analysis reflecting aspect cracks and then calculated water pressure distribution specifically by melting snow water in order to grasp a change of water pressure distribution of before-and-after construction of drainage facilities of well and drainage pipe. The landslide area has underground hydrology characteristics where melting snow and rainfall produces groundwater with pressure through the slide surface.
