Constructing new marine settlements
Home / Construction Plan for Geotextiles in Hydraulic Fill Soft Soil Foundation Treatment
Project Background And Objectives
In port construction, land reclamation and hydraulic fill projects, large-scale hydraulic fill foundations often consist of soft soil layers such as silt and silt sand, which have high water content, low bearing capacity and large settlement. Laying geotextiles in hydraulic fill foundations can achieve multiple functions, including isolation, drainage and reinforcement. This effectively improves foundation strength and stability, controls settlement and ensures the safety of subsequent road, wharf and storage yard construction.
Construction Conditions
Natural Conditions:
The construction area is a newly filled area with a thick layer of silt and sandy soil, high water content and a high groundwater level, which is significantly affected by tides.
Site Conditions:
Large-scale reclamation area requiring continuous geotextile installation.
Material Requirements:
Geotextiles are made of polypropylene woven fabric, polyester filament woven geotextile and needle-punched non-woven geotextile and have good tensile strength and water permeability.
Deployment And Preparations
Overall Deployment:
The construction is carried out in sections and layers, with sand blowing backfilling first and then laying geotextiles.
Equipment:
Excavators, bulldozers, dredging/pumping vessels, surveying tools.
Personnel:
Technical engineers, surveyors, operators, safety officers.Preparation:
Site clearing, fill schedule planning, geotextile transport and storage.
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
- Strictly inspect the quality of geotextile tube bags, sand materials and filter geotextiles to ensure that they meet the project requirements.
- Control the filling thickness to about 0.5-2.0m (determine the filling height based on the tensile strength of the geotube cloth) and inspect each batch in sections.
- RTK measurement of crest elevation and alignment, deviation ≤ ±150mm.
- After completion, the geotube bags should be covered promptly to avoid exposure to sunlight and aging.
- Implement “three-level inspection system”: self-check, project re-check, supervisor acceptance.
Safety And Environmental Measures
- Workers must wear life jackets and helmets.
- Provide sufficient lighting for night work.
- Assign personnel to monitor pumping operations.
- Avoid construction during fish spawning or bird migration seasons.
- Install silt curtains to minimize sediment leakage and protect water quality.
Geotextile Fabrics: Foundation Stability Challenges
Pain Point 01
Low Tensile Strength Causes Excessive Settlement
Customer Concern:
The bearing capacity of the foundation in land reclamation is uneven and traditional geotextiles (tensile strength <30KN/M) are easy to tear, resulting in uneven foundation settlement of more than 300mm, affecting subsequent wharf construction.
Solution:
By selecting high-strength woven geotextile (tensile strength 35KN-250KN/M) and combining it with the “sand-gravel-geotextile” composite cushion design, the uneven settlement of the foundation is controlled within 150mm, meeting the requirements for the later construction of the port terminal.
Pain Point 02
Imbalanced Water Filtration Performance
Customer Concern:
The water filtration rate of geotextile is slow (less than 0.5m/h), which leads to uneven foundation settlement and silt bags, increasing the difficulty of subsequent construction.
Solution:
By optimizing the pore structure of geotextiles (equivalent pore size 0.1-0.3mm), the water filtration rate is increased to 1.2m/h and the construction efficiency is improved by 60%.Pain Point 03
Insufficient Aging Resistance
Customer Concern:
The aging resistance of the geotextile cannot meet the requirements of one year of natural exposure at the project site. During the exposure process, the geotextile becomes brittle, resulting in uneven settlement.
Solution:
Our geotextiles can withstand 365 days of exposure in any region of the world, with a strength retention rate of more than 70% and an elongation rate of more than 70%, ensuring the fabric is intact.Constructing new marine settlements
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