3048
Proceedings of the 18
th
International Conference on Soil Mechanics and Geotechnical Engineering, Paris 2013
s
u
(kPa)
c’ (kPa)
ɸ
’ (deg)
Back
Analysis
(FOS=1.1)
30+5.5z
1
0
35
Triaxial
(CUP)
N/A
0
36-39
Geonor vane
15 to 120 with
depth
N/A
N/A
CPT
25 to > 200 with
depth
N/A
N/A
Design
(static)
0 (for z < 2.5m
depth)
30 + 4z (for z >
2.5m depth)
0
0 (for z<2.5m
depth)
32 ( for z>2.5m
depth)
Design
(seismic)
0 (z<2.5m depth)
24+3.2z
(z>2.5mdepth)
0
27
1
Most likely lower bound, assuming a factor of safety of 1.1
6 CONCLUSIONS
The design of a new landfill has been based on the properties
and performance of an existing landfill that has been operating
for 20 years. The landfills are operated in cells, with facing
bunds retaining sludge, constructed in lifts using “upstream”
construction. The characteristics of the sludge in situ are
governed both by the nature of the material and the operation
procedures. Key to the process is the limited height of each lift,
together with the period of desiccation between lifts.
To investigate the properties of the sludge for design input,
boreholes and CPT’s were put down through completed landfill
cells of different ages. The tests showed the in situ sludge to
have significant strength increase with time and depth, with
pore pressures well below hydrostatic conditions. The need to
check liquefaction potential is self-evident. The sludge was
assessed to be non-liquefiable by a number of methods.
7 ACKNOWLEDGEMENTS
The authors thank New Zealand Steel Ltd. for their permission
to publish this paper.
8 REFERENCES
Boulanger, R.W. & Idriss, I.M. 2006. Liquefaction susceptibility criteria
for silts and clays.
ASCE Journ. Of Geotech. and Geoenv. Eng
.,
Vol. 132, No. 11, November.
Boulanger, R., and Idriss, I. M. 2007. Evaluation of Cyclic Softening in
Silts and Clays.
Journal of Geotechnical and Geoenvironmental
Engineering
, 133:6, 641-652.
Bray, J.D. and Sancio, R.B. 2006. Assessment of the liquefaction
susceptibility of fine-grained soils.
Journal of Geotechnical and
Geoenvironmental Engineering
, ASCE, July 2008, Vol. 134, No.
7, pp. 1031-1034.
Cetin, K. O., Seed, R. B., Der Kiureghian, A., Tokimatsu, K., Harder, L.
F., Kayen, R. E., and, Moss, R. E. S. 2004. Standard Penetration
Test-Based Probabilistic and Deterministic Assessment of
Seismic Soil Liquefaction Potential.
Journal of Geotechnical and
Geoenvironmental Engineering,
130, 1314-1340.
Lunne, T., Robertson, P.K. and Powell, J.J.M. 1997.
Cone Penetration
Testing
. Spon Press, London.
Moss, R. E. S., Seed, R.B., and, Olsen, R. S. 2006a. Normalizing the
CPT for Overburden Stress.
Journal of Geotechnical and
Geoenvironmental Engineering
, 132, 378-387.
Moss, R. E. S., Seed, R.B., Kayen, R. E., Stewart, J. P., Der Kiureghian,
A., and, Cetin, K.O. 2006b. CPT-Based Probabilistic and
Deterministic Assessment of In-Situ Seismic Soil Liquefaction
Potential.
Journal of Geotechnical and Geoenvironmental
Engineering
, 132, 1032-1051.
Seed, R.B., Cetin, K.O., Moss, R.E.S., Kramer, A., Wu, J., Pestana, J.,
Riemer, M., Sancio, R.B., Bray, J.D., Kayen, R.E. and Faris, A.
2003. Recent advances in soil liquefaction engineering: A
unified and consistent framework. Keynote presentation,
26th
Annual ASCE Los Angeles Geotechnical Spring Seminar
, Long
Beach, California.
Zhang, G., Robertson, P.K., and Brachman, R. W. I. 2002. Estimating
Liquefaction-Induced Ground Settlements from CPT for Level
Ground.
Canadian Geotechnical Journal. 39
, 1168-1180.
d with the
assessment
al. (2004),
s are very
2.6) and
ction. The
m CRR
7.5
)
for a peak
exceedance
recommend a ratio of cyclic undrained to static strength for
natural clays/silts is 0.8. Therefore the static strength was
reduced by 20%.
Table 1. Sludge design parameters used for design of East Landfill
Test Method
Undrained
Drained
s
u
(kPa)
c’ (kPa)
ɸ
’ (deg)
Back
Analysis
(FOS=1.1)
30+5.5z
1
0
35
Triaxial
(CUP)
N/A
0
36-39
Geonor vane
15 to 120 with
depth
N/A
N/A
CPT
25 to > 200 with
depth
N/A
N/A
Design
(static)
0 (for z < 2.5m
depth)
30 + 4z (for z >
.
depth)
0
0 (for z<2.5m
depth)
32 ( for z>2.5m
depth)
Design
(seismic)
0 (z<2.5m depth)
24+3.2z
(z>2.5mdepth)
0
27
1
Most likely lower bound, assuming a factor of safety of 1.1
6 CONCLUSIONS
The design of a new landfill has been based on the properties
and performance of an existing landfill that has been operating
for 20 years. The landfills are operated in cells, with facing
bunds retaining sludge, constructed in lifts using “upstream”
construction. The characteristics of the sludge in situ are
governed both by the nature of the material and the operation
procedures. Key to the process is the limited height of each lift,
together with the period of desiccation between lifts.
To investigate the properties of the sludge for design input,
boreholes and CPT’s were put down through completed landfill
cells of different ages. The tests showed the in situ sludge to
have significant strength increase with time and depth, with
pore pressures well below hydrostatic conditions. The need to
check liquefaction potential is self-evident. The sludge was
assessed to be non-liquefiable by a number of methods.
7 ACKNOWLEDGEMENTS
The authors thank New Zealand Steel Ltd. for their permission
to publish this paper.
8 REFERENCES
Boulanger, R.W. & Idriss, I.M. 2006. Liquefaction susceptibility criteria
for silts and clays.
ASCE Journ. Of Geotech. and Geoenv. Eng
.,
Vol. 132, No. 11, November.
Boulanger, R., and Idriss, I. M. 2007. Evaluation of Cyclic Softening in
Silts and Clays.
Journal of Geotechnical and Geoenvironmental
Engineering
, 133:6, 641-652.
Bray, J.D. and Sancio, R.B. 2006. Assessment of the liquefaction
susceptibility of fine-grained soils.
Journal of Geotechnical and
Geoenvironmental Engineering
, ASCE, July 2008, Vol. 134, No.
7, pp. 1031-1034.
Cetin, K. O., Seed, R. B., Der Kiureghian, A., Tokimatsu, K., Harder, L.
F., Kayen, R. E., and, Moss, R. E. S. 2004. Standard Penetration
Test-Based Probabilistic and Deterministic Assessment of
Seismic Soil Liquefaction Potential.
Journal of Geotechnical and
Geoenvironmental Engineering,
130, 1314-1340.
Lunne, T., Robertson, P.K. and Powell, J.J.M. 1997.
Cone Penetration
Testing
. Spon Press, London.
Moss, R. E. S., Seed, R.B., and, Olsen, R. S. 2006a. Normalizing the
CPT for Overburden Stress.
Journal of Geotechnical and
Geoenvironmental Engineering
, 132, 378-387.
Moss, R. E. S., Seed, R.B., Kayen, R. E., Stewart, J. P., Der Kiureghian,
A., and, Cetin, K.O. 2006b. CPT-Based Probabilistic and
Deterministic Assessment of In-Situ Seismic Soil Liquefaction
Potential.
Journal of Geotechnical and Geoenvironmental
Engineering
, 132, 1032-1051.
Seed, R.B., Cetin, K.O., Moss, R.E.S., Kramer, A., Wu, J., Pestana, J.,
Riemer, M., Sancio, R.B., Bray, J.D., Kayen, R.E. and Faris, A.
2003. Recent advances in soil liquefaction engineering: A
unified and consistent framework. Keynote presentation,
26th
Annual ASCE Los Angeles Geotechnical Spring Seminar
, Long
Beach, California.
Zhang, G., Robertson, P.K., and Brachman, R. W. I. 2002. Estimating
Liquefaction-Induced Ground Settlements from CPT for Level
Ground.
Canadian Geotechnical Journal. 39
, 1168-1180.
