Seawalls serve as the primary barrier against storm surges and wave erosion, safeguarding coastal territories, residents’ livelihoods, and industrial development. Traditional seawall construction materials—such as stone, cast-in-place concrete, and hot-rolled steel sheet piles—exhibit significant shortcomings in the harsh marine environment characterized by high salt fog, extreme wet-dry cycles, and seawater immersion: stone has limited erosion resistance and disrupts ecosystems; concrete is prone to carbonation and freeze-thaw damage, lacking sufficient durability; steel is susceptible to electrochemical corrosion, requiring frequent rust removal and anti-corrosion maintenance, resulting in high overall costs. In contrast, plastic steel sheet piles, with their core performance advantages of corrosion resistance, high strength, and ecological compatibility, have become the preferred material for upgrading existing and constructing new coastal defense embankments. They provide an efficient solution for achieving structural safety upgrades, optimizing operation and maintenance costs, and enhancing ecological functions.
The precise adaptation of plastic steel sheet piles to the demanding conditions of coastal defense structures stems fundamentally from their targeted performance design and material advantages. Material-wise, their core utilizes modified high-strength PVC or PVC-composite materials with stable molecular structures. This allows direct resistance to seawater, salt spray, and marine microbial corrosion without requiring additional anti-corrosion coatings, achieving a design service life exceeding 50 years—far surpassing conventional steel’s operational lifespan. Structurally, they feature high-moment-of-inertia CT-type and Z-type cross-sections paired with precision tongue-and-groove joints. When assembled, they form continuous, seamless impermeable walls that effectively resist lateral pressures from strong waves and winds while blocking seawater seepage pathways. This prevents potential hazards like piping and scouring at the embankment foundation, ensuring overall structural stability.
Eco-friendliness stands as a core distinguishing feature of plastic-steel sheet piles compared to traditional coastal defense materials, aligning with contemporary “ecological seawall” construction principles. The material itself employs an eco-friendly formulation free of harmful components like lead and heavy metals, preventing pollutant release into marine environments. Structurally, certain ecological plastic steel sheet piles incorporate continuous ecological holes or vegetation growth channels. These ensure seawater circulation and support the migration and habitation of marine life such as fish and shrimp, while promoting root growth of embankment vegetation. This achieves ecological connectivity between “embankment-water-biota,” fulfilling dual objectives of slope stabilization and ecological restoration. It is particularly suitable for coastal wetland reserves, scenic seawalls, and other coastal defense projects with high ecological requirements.
As coastal economic development raises safety standards and ecological demands for coastal defense projects, coupled with the deepening of green and low-carbon construction concepts, plastic-steel sheet piles are gradually replacing traditional materials. Their comprehensive advantages—corrosion resistance, durability, efficient construction, and economic environmental friendliness—are positioning them as the mainstream innovative direction for coastal defense embankment construction. Looking ahead, further advancements in material modification techniques and structural design will continuously enhance plastic steel sheet piles’ resistance to wind and wave forces, low-temperature brittleness, and other properties. This will provide stronger technical support for building safer, more durable, and more eco-friendly modern coastal defense barriers.
