Deploying GeoTextile Tubes

Southern Dredging and Marine can provide you with GeoTextile Tubes and Bags for your next project. Our services include the installation of the bags to receive the spoils from dredging, or to be used for erosion control or shoreline protection. Contact us to learn more.

Deploying & Connecting the Tubes or Bags

After installing the drainage media, measure the width of the dewatering cell and mark the location of the center of each tube unit. Position the first unit such that the center of the roll is centered at the designated mark. Unroll the tube from the core. The ports shall be on the center line and the tube will be unfolded from the center.  

After placing, the tubes should be anchored for initial filling by means of the side loops on the tube.  Anchor stress must be alleviated after tube begins to fill.  If needed, sandbags may be used to keep tube from being blown out of position.  

Size the discharge lines coming from a dredge or pump so that the flow inside of the line is at a speed to keep the pipe full and prevent settlement of solids.  Lay the lines straight whenever possible and minimize the amount of elbows and T's to prevent clogging inside the discharge line.  Connections should be equal to the diameter of the discharge line.  The pressure in the discharge line should not exceed 6 psi when the flow is going into the one or multiple dewatering units.  The warning tag on each tube refers to the maximum allowable gallons per minute to that tube. 

For dewatering applications with low percentages of sand,  adding polymers will help increase dewatering, improve effluent quality, and achieve higher percentage solids in the dewatered sludge.  Polymer selection, dosing, and mixing operations shall be optimized by the POLYMER SUPPLIER  with bench scale tests as part of the planning process.   

For projects with multiple dewatering tubes, a manifold system may be used to distribute the sludge to fill one unit at a time or multiple units at a time.  The manifold should be constructed using either  “T’s” or “Y’s” fittings and valves. Pinching valves on a flexible line between the fitting at the manifold and the line connected to the fill port is installed to control the filling of one or multiple tubes at a time. As one unit is filled, the pinch valve for the next geotextile tube can be opened and the pinch valve for the first tube can be closed completely, or partially closed to maintain a flow into this unit that balances the inflow to the dewatering rate of the unit. 

Create a start up and daily checklist to follow throughout the operation, before the starting the project.  Check for leaks in the piping and connections.  Verify the working condition of the pumping system, the polymer mixing system, and the injection system for acceptable performance.  Inspect the site to insure that there are no abnormal situations and that all safety precautions are in place to avoid accidents.  Put the equipment into operation once everything is working as planned.

Stacking the Containers for a Smaller Footprint

Stacking the dewatering tubes in layers may be necessary on projects with large volumes with a limited footprint for the dewatering cell.

Fill and dewater completely the lower layer of geotextile tube units to support the next layer and all subsequent layers.  All units on a supporting layer must be dewatered to the same level.  

If the "V-Notch" or void space between each unit is large, such as for large  circumference tubes, this space shall be filled with suitable material, such as hay bales, to level  the surface before the next layer of tubes can be placed or “nested”, and to prevent the next layer from collapsing into the space between the lower geotextile tubes. 

Each subsequent layer must be centered directly over the "V-Notch" of the lower layer of containers. Each subsequent layer shall be a minimum of 10 shorter than the lower layer and centered on the lower layer, so that each end is positioned  a minimum of 5 feet in from the ends of the lower layer.   The top tube shall be anchored from both sizes by means of the side loops in order to maintain position during initial  filling.  The anchor stress must be removed after filling process begins and tube rises.   When filling each layer, any individual tube must not exceed the recommended filling  height.  The maximum height must be measured from the lowest point of a geotextile tube to the maximum upper   surface of the unit. We operate in the Caribbean or South America such as Dominican Republic, Cayman Islands, Trinidad & Tobago, St. Lucia, Bahamas, Barbados, Antigua, Anguilla, Aruba, Martinique, Grenada, Belize and Guadeloupe, as well as in Florida and most of Central America.