Application of Sliding Block Concept to Geosynthetic-Constructed Facilities - Reinforced Soil Engineering: Advances in Research and Practice - page 102

therefore k v , which varies with time. The procedure implies that a separate set of
vertical acceleration records is needed in addition to that of horizontal
acceleration (Fig. 3a) . However, the vertical acceleration may be considered in a
simplified manner using a ratio of peak vertical seismic coefficient to peak
horizontal seismic coefficient. That is, l

The vertical acceleration is
thus assumed to be in phase with the horizontal acceleration.
For the horizontal block and reinforced soil block, the yield seismic
coefficient and displacement correction factors are rewritten as follows for the
simplified analysis:
Block sliding along horizontal plane:

¼ k vo = k ho :

tan f

k hy ¼ ð 15 Þ

1 þ ltan f

ZZ

¼ð þ Þ ð

k h 2 k hy Þ

ð Þ

x 1 ltan f g·dt 16

Reinforced soil:

W B C ds tan f þ W A tan ð f 2 a Þ L

k hy ¼ ð 17 Þ

W B ð 1 þ lC ds tan f Þþ W A ½ 1 þ ltan ð f 2 a Þ L

ZZ

¼ð þ Þ ð

k h 2 k hy Þ

ð Þ

x 1 lC ds tan f g·dt 18

Note that Eqs. (16) and (18) are the same since C ds tan f represents
the angle of friction of the soil -geosynthetic interface. The simplified approach
to include vertical acceleration has been discussed in Ling and Leshchinsky
(1998).

5 LANDFILL COVER

Geomembrane is used as liquid barrier in waste containment. It is covered by
a layer of cohesive soil as a protection medium. Because of the low frictional
resistance between soil and geomembrane, the failure of cover soil typically
occurs along the soil -geomembrane interface. It may also occur along the
interface of geosynthetics depending on the interface strength. The static
stability analysis of landfill cover soil, considering end effect (finite slope),
has been presented by Giroud and Beech (1989) and Koerner and Hwu
(1991).