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8/12/2019 ascife.27510.0001
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Externally
applied
total
stress
Flexible impermeable membrane
Pore
water
pressureu
u Saturated soil
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X X
u
u
u
1
u u
u
u
p
p
A
u
u
(p/A u)A
u
A+
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D
Unit column
Total stresses Pore water
pressure
Effective
stresses
u
v (vu)
(hu)h
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Piezometers
Rapidlyconstructed
embankment
Ground
level
Water
level
t>> 0
t> 0
t= 0
t=
u/ w
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1
3 = 3
3
ua/ wub/ w
u/ w
(13)
+ 0
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96
576
496
96
336
416456
1116
1116
1036
416456
1586
1036
1586
3136
3216
3136
3136
3136
24
210
Gravel
Clay
Gravel
Clay
Gravel
Clay
Gravel
Clay
(u)u kPa
416
416
496416
496416
210
210
155
155
416456
202
4
4
0
Long term
Short term
336
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p
p = o
(u) = p
t = o
u = p
(u) = p
v =o
t = u = o
(u) = p+p
v >o
t > o
o
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p pp
u = o
(u) = p+p
t = o
u = p
(u) = p+p
v =o
t = u = o
(u) = p
v >o
t > o
p u
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Original ground
water level for
static water
table
Final groundwater level for
steady seepage
Equipotential
line
p
hf
ho
End of excavation
pore water pressure
Depth of cut
Shear stress on slip
line through P
Time
Time
Time
Time
(a)
(b)
(c)
(d)
Porewaterpressure
h0
w
Effectivestress
atP
Factorofsafet
y
Rapid
construction
Pore pressure
dissipation
Pore pressure
equilibrium
hfw
atP
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Equilibrium
ground water
levelh
P
End of loading
piezometric level
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Height of fill
Shear stress on slip
line through P
Time
Time
Time
Time
(a)
(b)
(c)
(d)
Porewaterpressure
hw
Effectivestress
atP
Factorofsafety
Rapid
construction
Pore pressure
dissipation
Pore pressure
equilibrium
atP
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= 0c = su
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