48
Geotechnical News • March 2018
THE GROUT LINE
in-hole packer and the grout pump,
to gather pressure and flow data. All
the collected data are transmitted to
the grouting software, which in turn
regulates the pump pressure and flow
rate to maintain their values within the
required limits. The software automat-
ically computes the effective pressure,
correcting the “raw value” (measured
by the flowmeter) taking into consid-
eration all the dynamic and static head
losses. The grouting software triggers
mix changes based on pre-set criteria
for pressures or volumes within the
bounds of the refusal criteria.
A centralized operations center (“con-
trol room”) is setup to manage and
monitor the grouting operations across
the dam from a single location (Figure
13). At the grouting place, technical
operators are allowed to check all the
parameters and the grouting behavior
through tablets, directly connected
to the “manifolds” and the “control
room”. A vocal and writing messag-
ing system (through the optical fibers)
allowed the direct communication
between the operators in the gallery
and the “control room”.
The gathered grouting data and pro-
cess behavior are recorded, analyzed
and archived by the software. The
software produces “in-real-time”
reports for each stage and summary
of the main grouting data for each
borehole, and updates the database for
the whole site, including grout takes
(volumes and solids) and grouted
length (including number of stages
and boreholes). Likewise, the software
creates (and automatically updates) the
drawings representing the position and
detailed grout take of all the stages of
all the holes, along the grout curtain
profile.
Progress and challenges
Significant progress has been achieved
since mobilization a year and a half
ago and the start of grouting one year
ago. The project has faced many chal-
lenges and the MoWR-USACE-Trevi
team have worked closely to solve
them. Successes and challenges are
offered below as credit to the Iraqi-
American-Italian team that continues
to push this project to completion for
the good of Iraq and its citizens.
• One-thousand-person housing
complex practically completed.
Completion was delayed due
to contractual disputes between
subcontractors. At the begin-
ning of the project staff had to be
mobilized in a staggering fashion
according to the completion of the
housing units.
• Completion of three mixing plants
and six ancillary buildings. Com-
pletion of the plants was timed to
the start of grouting on new gallery
or crest grouting areas. Construc-
tion schedules were difficult to
maintain due to the limitations of
the local subcontractors.
• Installation of grout mix, bentonite
and water piping systems; and
electrical trays and lines from
mixing plants 1 and 3 to the crest
of the dam. The lines had to be
installed on two to one (H:V) rip
rap covered slopes and along the
crest of the dam. Construction was
complicated due to difficulties in
getting needed materials to the
site, space limitations, traffic and
existing utilities.
• Drilling and grouting of over 1,835
grout holes along the crest (east
and west abutments) and gallery.
A continuous grout line along the
length of the dam has been com-
pleted. This number of holes has
been completed despite large grout
takes, high back pressures, space
limitations, difficult geology, work
force new to drilling and grouting
work, etc. The team has overcome
these difficulties and more by
focusing on the work and open
communication. The difficulties of
procuring and transporting equip-
ment, tools and supplies to keep
the drilling and grouting effort
uninterrupted are magnified due to
the complexities of the site being
within a war zone.
• The equipment and grouting
methods employed at the site are
heavily dependent on electronic
systems and grouting software for
communication, data gathering,
processing and reporting. Drill-
ing rigs, mixing plants and BGUs
incorporate electronic controls that
are relatively new to MoWR staff.
Under the Contract conditions
the Contractor has trained over
100 MoWR staff on the opera-
tion, maintenance and repair of
the equipment and mixing plants.
However, MoWR-USACE-Trevi
team has extended the training
concept further to one of integrat-
ing MoWR personnel into the
Contractor’s crews with the objec-
tive of bringing MoWR work force
to a level where they can take re-
sponsibility for directly executing
the work on their own. Currently
over 115 MoWR staff have been
fully integrated into the project,
the objective is to have approxi-
mately 250 workers integrated by
the end of 2018.
Figure 13. Activity in the
“
control room
”
(Computerized grouting control
system).
