March/April 2023 - 96

The seven new Corpus Christi LNG
trains will add more than 10 million tons
(9 million tonnes) per annum of
production capacity to Cheniere's
existing capability, with plans for two
more trains in the near future. These
LNG trains will be comprised of vertical
and horizontal pressure vessels, tanks,
heat exchangers, pumps and compressors.
Each processing train will be
approximately 670 by 500 ft (204 by
152 m). The processing equipment
within individual LNG trains will be
constructed over large pile compensated
mat foundations or individual pile caps.
These foundations will all be supported
on drilled displacement piles. The piles
are being installed through cement
mixed stabilized soils, very soft dredged
material and bauxite, and terminate
within the underlying natural very stiff
clays or dense sands.
The deep foundation contractor is
work ing under a cons t ruc t i on
agreement with Bechtel Energy to
install drilled displacement piles
beneath all seven trains at the Corpus
Christi Stage 3 expansion of the existing
Cheniere LNG plant. In March 2022, it
Drilling piles at the Plaquemines Parish site
began the first of two sets of test piles at
the new terminal. The second test in
July led directly to an August 2022
installation start date for approximately
27,000 piles of 14, 18, and 24 in (355, 450
and 600 mm) diameters.
Installing Drilled, Full
Displacement, Cast-in-Place
Concrete Pile
The deep foundation system used in
these projects is a dri l led, ful l
displacement, cast-in-place concrete
pile installed by fixed mast drill rigs
capable of applying high rotational
torque and crowd forces to the tooling. A
single-pass process eliminates drilling
spoils by compacting the soil into the
surrounding ground as the pile is
installed, thereby densifying and
improving the soil and creating higher
load bearing capacities. As the pile
advances into the ground, the partial
displacement auger transports soil to
the full displacement element where
all cuttings are compressed laterally
against the sidewalls of the borehole,
causing densification of the soil profile.
A centralizer at the bottom of the drill
mast maintains horizontal control of
the tooling. The heavy wall pipe/drill
stem serves as a temporary casing that
follows the tool and stabilizes the
borehole. Upon attaining the specified
depth, advancement of the tool is
stopped. A full-length center reinforcing
bar is guided by a drill tender
into the drill stem until it reaches a
conical shaped recess in the center of
the sacrificial endplate.
Prior to lifting the tool, the temporary
casing/drill stem is filled with a selfconsolidating,
high slump, coarse
aggregate concrete. The temporary
casing functions as a tremie pipe from
which pressurized concrete flows
through while the tooling is withdrawn,
leaving the endplate at the pile tip. This
method of concrete placement ensures
piles are formed each time without risk
of cross-sectional reductions.
At the Plaquemines job site, the
contractor provided a solution to assist
removing of excess pile concrete above
top of pile elevation, closer to grade, by
utilizing five tracked vacuum trucks to
suction the grout within 2 in (50 mm) of
pile cutoff elevation, in lieu of hand
dipping or requiring pile cutters or hand
chipping after excavation. The drill
tenders complete the pile installation
process by placing a prefabricated
reinforcing steel cage into the fresh
concrete. Pile reinforcing design was
performed using pile loads provided by
the client and pile load test data
obtained from the load test program.
All aspects of the drilling process and
concrete placement are observed and
recorded by automated monitoring
equipment. Upon completion of each
pile, the drill rig transmits installation
data and pile
created and distributed to project managers
and quality control professionals.
The system is installed by Fundex
fixed-mast drill rigs. The Plaquemines
project utilizes nine F3500 rigs and one
F5600 machine. The contractor is
currently installing 130 piles each day
at the this site, and another rig will soon
be added, increasing production to
96 * DEEP FOUNDATIONS * MAR/APR 2023
logs. Daily reports are
March/April 2023

Table of Contents for the Digital Edition of March/April 2023
