May/June 2023 - 47

Three New Journal Articles
DFI Journal editors announce the availability of three
papers that can be downloaded ahead of print online at
www.dfi-journal.org. One paper is part of a special issue and
the other two are part of Vol. 17, Issue 1.
The paper " Comparative Study on Ground Improved by
Stone Columns and Ground Improved by Hybrid Concrete
Columns " by Chulmin Jung, William Chong, Pratishkumar
Maheshwari, Shazlena Shariff, Penmetsa Sreenivasa and
Kwanseon Hong, is an addition to the DFI Journal Special Issue
on Ground Improvement being published this year.
The paper provides a detailed discussion and comparison
of two deep ground improvement techniques - stone
columns and hybrid concrete columns (HCCs) - in terms of
design, construction procedure and performance through a
case history from a recent petrochemical project in Malaysia.
Two full-scale group load tests were conducted on test
columns built prior to construction of production columns
and used to calibrate the analytical models adopted for the
design of stone columns and HCCs. Test results from both
experimental investigations are analyzed and suggest more
favorable improvement results for the stone column
technique. The paper also summarizes the key calibration
techniques adopted at the project site for quality control
during construction. These calibration techniques can be
considered as useful guides for other project sites with
similar ground improvement methods proposed in similar
ground conditions.
Bengt Fellenius, Dr. Tech, P.Eng., has begun working on a
miniseries, " Dusting Off Old Masters, " which premieres in
Volume 17, Issue 2. This series revisits famous historical
papers that have shaped the analysis and design of pile
engineering using empirical data and the development of
design methodologies. Considering decades of lessons
learned, including the advances made in the deep foundation
engineering industry (e.g., new test technologies, updated
formulations, improved design methodologies), Fellenius
reanalyzes several of these key load tests to derive new
understanding, explain discrepancies, and provide additional
insights and interpretation of previous test results using
today's knowledge and software resources. As such, some old,
and some controversial " masters " are providing new value to
the profession and meaningful lessons learned.
The first paper in the series by Fellenius, titled " Analysis
of Tests on Piles in Want of Instrumentation, " revisits the
Meyerhof et al. (1981) paper that studies a precast concrete
pile driven into clay, as well as the McGammon and Golder
(1970) paper on pipe piles in sand and clay. Fellenius takes a
closer look at the interpretation of shaft and toe resistance for
both experiments. By reanalyzing the two experiments and
their results, Fellenius highlights the fact that " capacity " of a
purely shaft-bearing pile does not occur at the same
movement as the " capacity " of the pile bearing by
combination of shaft and toe responses. In addition, the lack
of instrumentation to separate capacities assigned to the two
components (friction and toe bearing) is evaluated, and the
ability to obtain a true back-analysis, even with today's
computational advances, is discussed.
The third paper avai lable now for preprint is
" Experimental Investigation of Helical Pile Performance for
Loess Deposit Improvement, " by Abolfazl Eslami, Fateme
Rostami, Sara Heidarie Golafzani and Mohammad
Arabameri. The author team utilizes the regional occurrence
of loess soils in Golestan province in Iran to investigate
whether the simultaneous effect of inundation and
preloading in helical pile installation is operative and
effective in improving loess soils. The effect of installation
conditions on loess collapsibility is studied via field
investigations of 10 full-scale pile static load tests and
physical modeling by the frustum confining vessel developed
at the Amirkabir University of Technology (FCV-AUT).
The results indicate that the simultaneous application of
crowd loading and water pressure during the installation of
helical piles results in collapsibility potential reduction due to
the soil treatment. Moreover, high or low crowd loads
accompanied by water pressure during pile installation bring
about similar load-displacement behavior of model piles
installed in FCV-AUT and full-scale helical piles. The authors
conclude that the applied improvement technique is effective
on loess soils given its small investment of materials,
machinery and equipment - while attaining the highest
possible bearing capacity ratio.
Accessing the Journal
An online subscription to the DFI Journal is available to DFI
members at no additional cost. By signing in at www.dfijournal.org
you can access all Journal papers since 2006.
Nonmembers can purchase individual articles for $25 each or
join DFI as an individual member for just $130/year to receive
online access to all DFI Journals.
2023 Journal Underwriters
Interested in being an underwriter? Contact magads@dfi.org
DEEP FOUNDATIONS * MAY/JUNE 2023 * 47
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May/June 2023

Table of Contents for the Digital Edition of May/June 2023
