Constructing new marine settlements
Home / Construction Plan for Coastal Protection and Restoration Using Geotextile Tubes
Project Background And Objectives
This project aims to create a continuous protective barrier by installing geotubes to resist wave erosion, reduce coastal erosion and promote mudflat sedimentation and ecological restoration. The construction area is located in a nearshore area that is severely eroded, so both protective functions and environmental protection must be taken into account.
Design Principles
Protection: Ensure stability of tubes under waves and tides without displacement or damage.
Sustainability: Structure should encourage sediment accumulation and gradual mudflat formation.
Cost-Effectiveness: Use locally available fill materials (such as dredged coarse sand) to reduce costs.
Environmental Protection: Minimize ecological disturbance during construction.
Main Materials And Equipment
Geotextile Tube Bags: Made of high-strength geotextile tube fabric, it is UV-resistant and wear-resistant.
Filling Material: Mainly dredged medium-coarse sand is used, with moderate mud content.
Pumping Equipment: Sand pumps, slurry pumps and pipeline system.
Auxiliary Equipment: Cranes, lifting gear, positioning buoys and surveying instruments.
Construction Procedure
STEP 01
Surveying And Foundation Preparation:
Use GPS/total station to measure and locate, clean up the silt in the construction area, excavate the foundation trench and lay high-strength geotextile, sand and gravel cushion layers when necessary.
STEP 02
Tube Fabrication And Placement:
Tube bags are sewn into bags, with a filling thickness of 0.5-2m for a single bag and an overlap of 1.0-2.0m between bags.
STEP 03
Sand Filling:
Sand-blowing vessels are used for filling in sections. Construction must be carried out at low tide, layer by layer and staggered laying to avoid continuous seams in the cofferdam sandbags.
STEP 04
Dike Formation:
The upper and lower layers are staggered and overlapped by 1.0-2.0m to form a stable embankment. The cross-section of the sandbags in the embankment should be trapezoidal or herringbone-shaped (wide at the bottom and narrow at the top). Appropriate settlement allowance should be reserved for the height of the embankment.
STEP 05
Slope Protection:
Lay inverted filter geotextile on the surface of the bag, dump graded gravel and boulders and then build mortar block stone slope protection with a thickness of about 0.4-1.0m to form a permanent seawall.
Quality Control Measures
- Strictly control the filling pressure, flow rate and speed to prevent the geotube bag from rupturing.
- Regularly check tube position to ensure no displacement.
- The filling material must meet the requirements of particle size and mud content.
Safety And Environmental Protection Measures
- Workers must wear life jackets and protective gear.
- Assign personnel to monitor pumping operations to prevent equipment failure.
- Avoid construction during fish spawning or bird migration seasons.
- Install silt curtains to prevent slurry leakage and water pollution.
Geotextile Tubes: Structural Safety & Durability Challenges
Pain Point 01
Rapid Material Aging Shortens Project Lifespan
Customer Concern:
Traditional geotextile tubes degrade quickly under UV exposure and seawater erosion, leading to strength loss, cracks and breakage within a year. This results in sand leakage, embankment failure and high repair costs.
Solution:
Use UV-resistant, high-strength geotextile tubes (tensile strength 35–250 KN/m, elongation >23%). With special treatment, the tubes can withstand natural exposure for 3 years in any marine environment, reducing embankment repair costs from the source.
Pain Point 02
Weak Seam Strength Causes Tube Rupture
Customer Concern:
Conventional tubes are stitched with portable sewing machines, with seam strength ≤30% of base fabric. When filled with sand, seawater pressure often tears the seams, especially in ports with large tidal differences.
Solution:
Adopt industrial four-line parallel stitching, ensuring seam strength ≥70% of base fabric. With trapezoidal staggered stacking, overall shear resistance improves by 40%, preventing chain reactions from local damage.Constructing new marine settlements
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