Civil Engineering Reference
In-Depth Information
CHAPTER 9
SLOPE STABILITY
ANALYSES FOR
EARTHQUAKES
The following notation is used in this chapter:
SYMBOL DEFINITION
a
Acceleration
a
max
Maximum horizontal acceleration at ground surface (also known as peak ground
acceleration)
a
y
Yield acceleration, which is defined as that acceleration that produces a pseudostatic
FS
1.0
c
Cohesion based on total stress analysis
c
Cohesion based on effective stress analysis
d
Downslope movement caused by earthquake
D
r
Relative density of soil
F
h
Pseudostatic lateral force
FS
Factor of safety
FS
L
Factor of safety against liquefaction
g
Acceleration of gravity
h
Depth below ground surface (for calculation of
r
u
)
H
Total thickness of liquefied layers
k
h
Seismic coefficient, also known as pseudostatic coefficient
k
v
Vertical pseudostatic coefficient
K
Factor used to adjust factor of safety against liquefaction for sloping ground
L
Length of slip surface
m
Total mass of slide material
M
Magnitude of design earthquake
M
L
Local magnitude of earthquake
N
Normal force on slip surface
N
Effective normal force on slip surface
(
N
1
)
60
N
value corrected for field testing procedures and overburden pressure
r
u
Pore water pressure ratio
s
u
Undrained shear strength of soil
T
Shear force along slip surface
u
Pore water pressure
9.1
