Geoscience Reference
In-Depth Information
The displacement along the soil-geomembrane interface is obtained as
h
0
ZZ
l
¼
ð
k
h
2
k
hy
Þ
g·dt
ð
25
Þ
where
H
Lhsin 2b
h
0
¼
cos b
þ
C
ds
tan fsin b
þ
ð
26
Þ
When the end effect is neglected (infinite slope), Eqs. (19), (24), and (22)
degenerate to the following expressions, respectively:
C
ds
tan f
ð
1
2
k
v
2
k
h
tan b
Þþ
k
v
tan b
þ
c
a
=
gH cos b
F
ds
¼
ð
27
Þ
k
h
þ
tan b
k
hy
¼
ð
1
2
k
v
Þð
C
ds
tan f
2
tan b
Þþ
c
a
=
gH cos b
1
ð
28
Þ
þ
C
ds
tan ftan b
h
0
¼
cos b
þ
C
ds
tan fsin b
ð
29
Þ
Figure 11
shows the factor of safety of a liner under different values of peak
earthquake acceleration. The factor of safety is reduced significantly with an
increase in peak acceleration and a reduction in friction angle. The geometries
and properties are included in the figure. The yield seismic coefficient are
calculated as k
hy
¼
0
:
1216 and 0.037 for a finite and infinite slope when C
ds
¼
0
:
The effects of the direct sliding coefficient on the magnitude of sliding are
:
6; and 0.2208 and 0.1428 when C
ds
¼
0
:
8
0
:
6
;
gives several
times larger displacement than that of C
ds
¼
8 based on a record of the
Northridge earthquake. The end effect of the liner is also shown in the figure.
The parametric studies to look into the effect of other factors are given in
Ling and Leshchinsky (1997). It has to be noted that effect of vertical
acceleration is not very significant for landfill liner.
0
:
6 CONCLUSIONS
Equations for the yield seismic coefficients and permanent displacement were
presented for reinforced soil retaining walls and landfill liner considering direct
sliding mode of failure. A simplified procedure to include vertical acceleration
was presented for yield acceleration and permanent displacement. The permanent
displacement would be a more rational criterion for performance-based design
under high seismic load.
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