September/October 2022 - 75

article titled " Evaluating Lateral Bracing
Code Requirements for Large Diameter
Foundations " was so compelling that a
revision to the 2024 IBC is in progress
that cites the DFI paper as a primary
reference.
Committee member Jon Sinnreich,
M.Eng., P.E., Load Test Consulting,
identified a potential shortcoming in
the use of strain gages to compute the
force distribution along a pile: they are
strongly dependent on the pile cross
sectional area and Young's Modulus.
Since ACIP and DD piles sometimes
have variations in diameter, there may
be errors in estimating the force distribution.
Concrete Stressmeters (CSMs)
were evaluated in Sinnreich's DFI
Journal paper titled " Application of the
Concrete Stressmeter for Augered Castin-Place
(ACIP) Deep Foundation
Testing " (2022 Volume 16 Issue 1). In
two case histories, the CSMs were found
to yield comparable and reasonable
force distributions with considerably
less effort and fewer assumptions.
Finally, in an effort to evaluate and
quantify improvement of soils during
the installation of DD piles, Anne
Lemnitzer, Ph.D., University of CaliCOMMITTEE
CHAIR A. DAVID MILLER, P.E.
Soil Mixing
The Soil Mixing Committee last met
during the S3 conference in Nashville.
We updated our ongoing research for
the second phase from George Onorato,
P.E., GEI Consultants, investigating the
effect of curing stresses on the
mechanical properties of soil-cement
mixed materials. The study evaluated
results from relatively broad datasets of
act ive si tes wi th di fferent soi l
conditions, allowing us to observe
interrelated data trends between
datasets. The findings indicate a
strength increase within samples
cured under a confining stress relative
to nonconsolidated samples. The
magnitude of the strength increase also
appears to be different for different soil
types. Finer-grained soils appear to
exhibit a larger relative strength
increase with confining stress relative
to predominately granular soils. This
project is currently wrapping up.
However, we are still hoping to obtain
independent coring data from soil
mixing sites to validate the data and
results of the field tests that were
conducted as part of this research. If
there are firms that can contribute by
providing coring data, please contact
the committee. We really need the data
to forward this research for the benefit
of all. It is important to mention that the
project names and locations of this
information can be kept confidential.
The results of this research provide
important insight into the in-situ
properties of soil mixed materials that
will be of interest to the entire industry.
We would like to thank all the industry
collaborators such as Keller, Bauer
Foundations, Kiewit Foundations,
Geokon, Geo-Solutions, Advanced Terra
Testing, Geotechnics Laboratory, Braun
Intertec, Fugro and George Filz, Ph.D.,
P.E . , V i r g i n i a Te ch , who have
contributed to this research thus far.
Another popular topic is the
sustainability of soil mixing, and in
particular alternative binders, spoils
reduction, spoils recycling and any
other green initiatives that promote
sustainable design and sustainable
construction practices within our
industry. From a carbon footprint
perspective, soil mixing aids in
reducing emissions by using the in-situ
soils to create the product, reducing the
amount of waste hauled off and the
amount of replacement materials
hauled into the site. We are looking at
the carbon footprint and the way it is
considered, and
long-term effects
that should also be
considered. The beneficial reuse of
spoil is another topic that can help with
the overall carbon footprint of a project.
Given that our product sector is busy
this year means we draw on our natural
resources, like cement and other scarce
binders. This chal lenges us as
constructors to build relationships with
the cement and fly ash industry to
ensure mat er i a l s are suppl i ed
consistently and economically to meet
the demands of infrastructure and
energy supply sites. We are exploring
ways to work with suppliers within the
industry to better deal with demand.
There are significant projects happening
from the U.S. Army Corps of Engineers
in Florida, Alaska, California and other
areas; new liquified natural gas facilities
throughout the Gulf Coast; several large
environmental closures, such ash ponds
and other facilities all drawing on the
same industry. All of this puts a strain
on resources and supply chain.
Therefore, alternative binders, additives
and further understanding of the actual
in-situ conditions may help to alleviate
some of this strain.
DEEP FOUNDATIONS * SEPT/OCT 2022 * 75
fornia, Irvine, performed an evaluation
of hundreds of load tests from DD piles
of various diameters and lengths, and
in various soil types. In her project
titled " Axial Capacities of Drilled
Displacement Piles Predicted by SPT
and CPT Based Methods, " Lemnitzer
presents her findings on the performance
of DD piles compared to
their predicted performance during
load testing.
Our committee is always looking for
new members who are eager to
contribute to our discussions and
research ideas.
September/October 2022

Table of Contents for the Digital Edition of September/October 2022
