Dredging is a water body excavation process. It has multiple objectives, including deepening and widening water bodies, constructing waterway projects, and land reclamation projects. In addition, dredging may also aid in water body clean-up, preserving aquatic life, and eliminating pollution in water bodies. Depending on your dredging necessities, you can hire or purchase two major equipment categories: mechanical dredgers or hydraulic dredgers.
What is Dredging?
Dredging is a process that involves taking out debris, sediments, and other materials from the bottom of water bodies, including rivers, lakes, seas, etc. It requires specialized machinery known as dredgers which aid in excavating the sediments and dumping them on the allocated placement area. Dredging is particularly beneficial in construction work as it primarily aids in creating foundations for waterway structures such as bridges, docks, or piers. Furthermore, construction site dredging facilitates the digging and filling of trenches to construct pipelines and tunnels.
Types of Equipment Used for Construction Site Dredging
The machinery used for dredging is divided into two major categories, mechanical and hydraulic dredgers, each with specific types outlined below.
Mechanical Dredgers
These dredgers excavate materials from the floor of water bodies using buckets. They are best suited to operate in confined areas. Mechanical types of dredges are named according to their scooping buckets:
1. Clamshell/Grab Type Dredger
This dredger consists of a cutting tool known as a grab that has wire-operated two half-shells. The excavated materials are filled in the half-shells then loaded on the barges. It is particularly beneficial when dealing with loose to medium-dense soils and sediments.
2. Backhoe/Dipper Dredger
This machine has a hydraulic arm and half-open shell dredging equipment. It is commonly used in shallow water bodies and near harbors and is more convenient in handling consolidated materials, clearing rocks, and other debris.
3. Bucket Dredger
A bucket dredger is stationary and equipped with buckets attached to a wheel or chain that circulates accumulating the excavated materials. The sediments unload onto a barge when the bucket is turned upside down in their return cycle to excavate more material.
Hydraulic Dredges
The functioning of hydraulic dredges is via a suction mechanism. They suck the dredged materials and water from the bottom of the water source. The main types of hydraulic dredges include:
1. The Hopper Dredge
This type of dredge works by sucking and loading the excavated materials onto one or more hoppers in the equipment. The hopper dredge sails to the placement area to dispose of the materials when the hoppers are full. It is suitable for dredging soft mud, dense sands, and clay. Its mobility comes in handy while operating in rough seas and high traffic areas.
2. Cutter Suction Dredge
This dredge sucks up sediments and other materials through an intake pipe at one end and pushes them out to the placement site through the discharge pipe. This dredge is cost-efficient as it directly excavates the materials to the placement site and the operations are simultaneous. A cutter suction dredge is efficient in areas with thick shoals and works in water bodies with varying depths.
