11.1 Classic Approach
155
Table 11.1 An example of
FoS obtained by engineers
studying a dam
Section
FoS Local
FoS mid
FoS Global
1—South
>1.5
1.24
1.36
2—North
>1.5
1.27
1.20
3—North
>1.5
1.26
1.26
4—South
1.02
>1.5
1.50
5—North
1.01
1.11
1.82
We focus on the North section of a dam where reportedly (see Tables 11.1 and
11.2):
• slopes are steeper than designed;
• failure is incipient toward the eastern abutment;
• there is a monitoring system, but there is limited information about the readings,
frequency, etc.;
Table 11.2 Factor of safety
details for two sections
(North and South)
Section North FoS
Section South FoS
B–B
1.302
–
–
A–A
1.295
C–C
1.448
646,290
1.265
646,290
1.645
646,356
1.02
646,356
1.573
646,406
1.245
646,406
1.336
646,456
1.279
646,456
1.578
646,506
1.264
646,506
1.395
646,556
1.132
646,556
1.313
646,630
1.109
646,606
1.451
646,656
1.246
646,656
1.08
646,706
1.079
646,706
1.441
646,756
1.025
646,756
1.423
646,806
1.017
646,806
1.312
646,856
0.998
646,856
1.39
646,906
1.192
646,906
1.502
646,956
1.202
646,956
1.356
647,006
1.117
647,006
1.358
647,056
1.059
647,056
1.394
647,106
1.004
647,106
1.583
647,156
1.235
D–D
1.578
647,206
1.277
E–E
1.393
647,256
1.35
–
–