Geosynthetics August/September 2021 - 18

Geosynthetic-reinforced column-supported embankments: Improving practice with better theory
(2017) also found that the ultimate value
happens at the normalized displacement
of approximately 10%.
According to the tensioned membrane
theory, the normalized net stress carried
by the geosynthetic reinforcement can be
estimated based on the normalized displacement;
therefore, the resistance curve
for the geosynthetic can be obtained.
Considering the downdrag force
According to the
tensioned membrane
theory, the normalized
net stress carried
by the geosynthetic
reinforcement can
be estimated based
on the normalized
displacement;
therefore, the
resistance curve for
the geosynthetic can
be obtained.
distribution and the one-dimensional
consolidation of the soil, the relationship
between the subsoil resistance
and the normalized displacement can
be established.
The combined resistance from the
geosynthetic reinforcement and the subsoil
can be obtained by adding their resistance
at the same normalized displacement.
The intersection of the combined
resistance curve with the GRC is the solution
for the normalized displacement
and the normalized stress on the geosynthetic.
The location of the intersection
depends on several factors including
but not limited to the dimensions or
properties of the embankment, the load
transfer platform, the geosynthetic and
the subsoil.
This unified method was verified
by two field studies reported in the literature:
(1) the full-scale experiment
by Briançon and Simon (2012) and (2)
the field project with long-term measurements
by van Eekelen et al. (2020).
Interestingly, the subsoil in the first
study was strong and stiff so that the
geosynthetic provided limited contributions.
In the second study, however, the
embankment lost subsoil support during
its service so that the geosynthetic provided
significant contributions. The verifications
of the proposed solution were
carried out by comparing the calculated
stress on the geosynthetic, the differential
settlement between columns and subsoil,
and the strains in the geosynthetic with
those measured. The comparisons show
18
Geosynthetics | August September 2021
excellent matching between the calculations
and the measurements.
Summary
This article provides a summary of the
third Dr. Robert M. Koerner Lecture
presented by the author at the 2021
Geosynthetics Virtual Conference and
demonstrates the importance of bridging
theory and practice for geotechnical
engineering applications through GRCS
embankments technology. The research
conducted by many researchers in the past
20 years have helped better understand
the mechanisms of the GRCS embankments
including soil arching, tensioned
membrane and column/subsoil interaction.
The effects of these mechanisms
depend on column/subsoil relative stiffness.
Theoretical solutions based on these
mechanisms have made it possible for
engineers to design GRCS embankments.
To address large discrepancies in calculated
stresses and tensile forces in the geosynthetic,
the author proposed a unified
practical solution based on the simplified
ground reaction curve and the interaction
diagram to improve the accuracy of the
design method.
Acknowledgments
I appreciate the Geosynthetic Materials
Association (GMA) for selecting me
for this great award and honor, and for
providing the opportunity for the distinguished
lecture. Professor Robert M.
Koerner is one of my role models who
has inspired and encouraged me to conduct
research by bridging theory and
practice. I am very thankful to the education,
mentorship and support I received
throughout my career in China, the U.S.
and beyond. Credits go to all researchers
and industries including my collaborators
and graduate students who have helped
advance this technology.

Geosynthetics August/September 2021

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