March/April 2022 - 88

Calculator, jointly developed by the EFFC
and DFI (at www.geotechnical
carboncalculator.com). The use of slag
cement type CEM III/A for construction
of piles, foundation caps and for soil
mixing was assumed, with a default
GGBS content of 51%, and a default factor
of 41% for recycled steel. The resulting
emissions saving with application of
DSM is 16%, and, if Portland cement
would have been used for pi le
construction, that value would have
risen to 38%.
Conclusion
Commercial plaza in Rybnik founded on DSM columns
relatively susceptible foundation
support. For the same foundation and
loading, a significantly stiffer DSM
design can be also applied, for example,
by increasing the area improvement
ratio of the treatment. Between points 1
and 2, other DSM solutions exist for the
same loading. Taking into account other
combinations of foundations, loads and
column patterns, a range of DSM
solutions can be encircled by connecting
a family of corresponding points 1 and 2.
A complementary range of piling solutions
can be drawn in a similar way.
When to Use DM and Why
without compromising functional
design criteria. This opens the space for
consideration of other criteria to aid the
selection process of the best foundation
method for each case.
Obviously, a potential financial
savings will be a benefit to look at. For
example, we can analyze the PLAZA
center case in Rybnik, where CFA piles
were replaced with DSM columns.
Compared to the original piling design,
the alternative proposal offered a
significant overall cost saving, roughly
45%, arising from a lower unit rate of
D SM c o l umn s
despite increased
total length (31%),
and a reduced total
volume of foundation
pads (27%) and
of steel reinforcement
(42%) due to a
more uniform support
of pad foundations.
Another
imporAltogether,
this reveals that an
overlapping area exists where piling
and DSM solutions may both be
applicable in the same range of loads
tant benefit could be reduced CO2
emissions. The calculations of CO 2
emissions for the PLAZA center were
conducted using a standardized Carbon
In the last 20 years, more than 1,200
deep soil mixing projects have been
successfully completed in Poland, and
some of the applications, like foundations
of wind turbines and bridges, were
among the earliest internationally. You
can review the five Polish papers
included in the proceedings of the
virtual Deep Mixing Conference in June
2021 for the picture of what is currently
happening in Poland in relation to deep
mixing.
DSM soil treatment, like any technology
in the geotechnical industry, is
not a one-size-fits-all solution. Additionally,
the topics discussed above are
not exhaustive regarding DSM ground
reinforcement. The provided best practices
summarize over 20 years of experience
and represent the current state of
knowledge and design.
Michał Topolnicki, Prof., Ph.D., D.Sc., is a
senior technical advisor and professor who
worked for 40 years at the Technical
University of Gdańsk in Poland. He joined
Keller in 1996 and developed Keller Poland.
From 2007 to 2013, he served as Keller's
business unit manager for North-East
Europe, and from 2013 to 2015, as the
director for large projects in Keller Holding.
Topolnicki has also co-authored three books
and authored about 170 papers.
88 * DEEP FOUNDATIONS * MAR/APR 2022
http://www.geotechnicalcarboncalculator.com
March/April 2022

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