UFC 4-150-06
12 December 2001
6-10.2.1.1 Pipeline, or suction, dredge. This dredge consists of a barge-mounted
centrifugal pump. A suction line, or pipe, extends from the pump beyond the bow and is
lowered to the bed by means of an "A" frame and ladder. At the end of this ladder, the
pipe moves along the bottom dislodging the material. The material is then pumped in a
slurry to a discharge line extending beyond the stern of the dredge. The material may
then be pumped to the disposal site through a discharge line. Using booster pumps
can extend the distance through which the material may be pumped. Sweeping the
suction pipe over an area at constant depth will result in the excavation of the channel
bottom. Pipeline dredges are not self-propelled, but move by forward-mounted swing
wires and aft-mounted walking spuds or wires. This type of dredge can be operated
safely only in the absence of moderate to high swell; it can excavate material ranging
from clays and silts to blasted rocks. The dredge is generally capable of dredging large
volumes of material. Pipeline dredges are usually limited to excavation depths of
approximately 60 feet. The rate of production will decrease with increased length of
discharge line, increased lift, and increased bed-sediment compaction.
6-10.2.1.2 Cutterhead dredge. This dredge consists of a pipeline dredge equipped
with a rotary cutter at the end of the ladder. The cutter is used to dislodge bed
sediments.
6-10.2.1.3 Dustpan dredge. This dredge consists of a pipeline dredge with a
dustpan-shaped head at the end of the ladder. The head is equipped with water jets
that are used to dislodge bed sediments.
6-10.2.1.4 Bucket-wheel excavator. This dredge consists of a pipeline dredge with
a bucket wheel rotating (on a horizontal axis) at end of the ladder.
6-10.2.1.5 Trailing suction dredge. This dredge consists of a self-propelled or tug-
assisted vessel. The hull of the vessel contains a hopper and the dredge is equipped
with one or two suction pipes (normally fitted with drag heads) extending below the hull
to the bed. This dredge usually operates while underway, drawing slurry by centrifugal
pumps to the hopper, where excess water is overflowed back to the waterway.
Sediment is discharged at the disposal site by opening doors located on the hopper
bottom or by pumping out the hopper. This dredge is a self-contained unit and is
capable of operating in higher swell conditions. Because the dredge is self-propelled, it
is capable of dredging material from sites which are large distances from the point of
disposal.
6-10.2.1.6 Hopper dredge. This dredge consists of a trailing suction dredge with a
ship shaped hull, a bridge, an engine room, and crew quarters. This dredge is typically
used for the dredging of estuary and river-mouth bars that are prone to ocean-swell
conditions.
6-10.3
Special Equipment.
6-10.3.1
High Solids-Content Dredge. This dredge consists of a floating system
capable of pumping high concentrations of solids through the use of compressed air. It
6-8
Previous Page
