Two forecast methods of slope failure time and results of their applications for seven landslide cases are presented. One is the three points method on the cumulative displacem nt curve, the other is the method of least squares for discrete points on that curve . The equations used to forecast the slope failure time are as follows:
(1) Equations for the method of three points
Saito's equations: (1)
Fukuzono's equation: (5) and (6)
Kawamura's equation: (8)
Omura and Tsuchiya's equation as: (11) and (12)
(2) Equations for the method of least squares
Saito's equation: (13), (16) and (17)
Fukuzono's equation: (19), (16) and (17)
Kawamura's equation: (21), (16) and (17)
Omura and Tsuchiya's equation: (23), (16) and (17)
Both methods are useful to forecast the failure time of slope . In a strict sense, the latter method in the tertiary stage can forecast more accurately than the former.