抄録
The safety factor of landslide is used as the important index predicting its long term stability and determining the control device. The effect of the groundwater level and the change of load by embankment or cutting on the safety factor of its landslide are treated as the important factors.
But, the effect of load change on the relation between the groundwater level and the safety factor is not yet discussed. How the critical level of groundwater, in which the safety factor is 1, changes according to the change of load is discussed.
As the result, it is pointed out that the embankment or cutting for the purpose of increasing the safety factor inversely happen to make decrease the safety factor according to the groundwater level. Moreover, it is pointed that the embankment or cutting for the purpose of increasing the safety for slowing down the creeping velocity happen to guide the slope to dangerous side by decreasing the critical level of groundwater.
Replacement of embankment or cutting by accumulation or melting of snow is the same result. It is necessarry for us to consider not only the safety factor but also critical level of groundwater in controlling the landslide.
