Environmental Engineering Reference
In-Depth Information
Table 5.2
( Continued )
Reference
Equation
Description
1
van Genuchten (1980)-
Burdine (1953)
n =
(a v b ψ) n v b ] m v b
[1
+
where
2
n v b
m v b =
1
exp a m 1
ψ
McKee and Bumb (1984)
(Boltzmann distribution)
n =
a m 1 =
curve-fitting parameter
n m 1
n m 1 =
curve-fitting parameter
where
w (ψ)
w r
n =
w s
w r
1
McKee and Bumb (1987)
(Fermi distribution)
n =
a m 2 =
curve-fitting parameter
1
+
exp[
a m 2 )/n m 2 ]
n m 2 =
curve-fitting parameter
where
w (ψ)
w r
n =
w s
w r
w s
Fredlund and Xing (1994)
w (ψ)
=
C(ψ)
ln e
(ψ/a f ) n f m f
a f
fitting parameter which is
primarily a function of air-entry
value of soil
n f
=
+
where
fitting parameter which is
primarily a function of rate of
water extraction from soil once
air-entry value has been exceeded
m f
=
ln ( 1
+
ψ/ψ r )
C(ψ)
=
1
ln[1
+
( 10 6 r ) ]
w (ψ)
w s
d =
fitting parameter which is
primarily a function of residual
water content
C(ψ)
=
correction factor which is
primarily a function of suction
corresponding to residual water
content.
=
w s
w r
Pereira and Fredlund
(2000)
w (ψ)
=
w r +
a p =
fitting parameter which is
primarily a function of air-entry
value of soil
n p =
1
+ ψ/a p n p
m p
fitting parameter which is
primarily a function of rate of
water extraction from soil, once
air-entry value has been exceeded
m p =
fitting parameter which is
primarily a function of residual
water content
Pham and Fredlund
(2005)
S 1 ,S 2 ,S 3 =
slope of straight line
portions of SWCC within each of
three zones
w u =
w 1 (ψ)
=
w u
S 1 log (ψ)
1
ψ<ψ aev
S 2 log ψ
ψ aev
w 2 (ψ)
=
w aev
ψ aev
ψ<ψ r
S 3 log 10 6
ψ
water content at 1 kPa
w aev =
ψ< 10 6 kPa
w 3 (ψ)
=
ψ r
water content at air-entry
value
w 1 , w 2 , w 3 =
water content in line
segments 1, 2, and 3, respectively.
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