Water conservancy projects constitute a vital part of the national economic infrastructure, and their retaining structures directly determine their safety, durability, and ecological sustainability. For a long time, the water conservancy retaining structure sector in China has relied on traditional materials such as steel sheet piles and concrete piles. While these materials can meet basic protection requirements, they have numerous shortcomings that run counter to the principles of green infrastructure. With the continuous advancement of polymer material technology, researchers have developed plastic-steel sheet piles centered on eco-friendly polymer-reinforced composite materials. Leveraging their advantages of “lightweight yet high-strength, eco-friendly, and efficient and convenient,” these sheet piles are driving the transition of water conservancy support structures toward low-carbon and ecological solutions, emerging as the preferred choice for water conservancy projects in the new era.
Traditional support materials have become a bottleneck hindering the high-quality development of water conservancy projects. Steel sheet piles have poor corrosion resistance, require frequent maintenance, have a service life of only 10–20 years, and are difficult to recycle after disposal; concrete piles are bulky, result in low construction efficiency, and their pouring and removal processes pollute the environment and damage ecosystems. Furthermore, traditional sheet piles lack adaptability and have insufficient waterproofing and seepage prevention capabilities, easily leading to safety hazards such as leaks and collapses, and failing to meet the demands of ecological water conservancy construction.
Amid the accelerated advancement of ecological water conservancy construction and the industry trend of “replacing steel with plastic,” plastic-steel sheet piles precisely address the numerous shortcomings of traditional materials. Manufacturers use eco-friendly polymers as the base material, combined with reinforcing fibers and formed through extrusion to create plastic-steel sheet piles. This design combines the corrosion resistance of plastic with the mechanical strength of steel (tensile strength: 43–44 MPa; flexural strength: 63–71 MPa), forming a complete green closed-loop system of “production–application–recycling.” This is gradually replacing traditional materials and reshaping the landscape of hydraulic support structures.
Environmental sustainability is the core advantage of plastic-steel sheet piles. Manufacturers employ low-energy-consumption processes to produce them without adding any harmful substances. Some models are specifically designed with ecological holes to cultivate aquatic life, addressing both support and ecological conservation needs. Upon project completion, workers can recycle and reuse the plastic-steel sheet piles 100%, aligning with the principles of low-carbon sustainable development. In the Chongming Taiping Shuhe River channel improvement project, the contractor utilized the ecological design of plastic-steel sheet piles, which not only reinforced the riverbanks but also successfully restored the ecological vitality of the waterway.
The combination of high efficiency, convenience, and cost control has accelerated the replacement of traditional materials with plastic-steel sheet piles. Weighing only 1/6 to 1/8 of traditional steel sheet piles, plastic-steel sheet piles allow for modular construction methods and easy operation. With a driving speed of 4–7 meters per minute, construction efficiency is 30%–80% higher than that of traditional sheet piles, making them highly suitable for emergency rescue projects. The overall cost of plastic-steel sheet piles is lower than that of traditional concrete structures, with production costs 20% lower than steel sheet piles. They have a lifespan exceeding 50 years and require minimal maintenance. In the Hengshan District sluice station and supporting projects in Zhuhai, the contractor’s use of this material not only improved construction efficiency but also kept material wastage to just 2–3%.
Their high adaptability, safety, and durability have further expanded the scope of application for plastic-steel sheet piles. Featuring a high-moment-of-inertia cross-section design and interlocking joints, plastic-steel sheet piles significantly enhance waterproofing, seepage prevention, and resistance to bending and lateral pressure. Manufacturers can customize specifications to meet project requirements, and workers can use specialized connectors to achieve flexible directional adjustments, making them suitable for various complex terrains. Additionally, they can withstand all kinds of harsh environments, effectively addressing the vulnerability of traditional materials to damage.
Currently, plastic-steel sheet piles are widely used in diverse scenarios such as river channel rehabilitation and bank reinforcement, becoming the mainstream choice for hydraulic support. In navigation channel projects in Haiyan and Haining, Zhejiang, contractors have adopted plastic-steel sheet piles, effectively leveraging their erosion-resistant advantages with remarkable results. In marine and urban scenic area projects, plastic-steel sheet piles have also fully demonstrated their corrosion resistance, environmental friendliness, and aesthetic appeal, aligning with construction requirements. Furthermore, Chinese enterprises have begun exporting plastic-steel sheet piles to Southeast Asia, with the foreign trade turnover of companies like Tongxiang’s “small business owners” continuing to rise, highlighting the market competitiveness of China’s plastic-steel sheet piles.
The transition from traditional “extensive protection” to the “ecological and efficient” approach of plastic-steel sheet piles represents not only a technological upgrade in support materials but also a profound shift in the philosophy of water conservancy construction. As relevant policies and technical standards continue to improve, plastic-steel sheet piles will, with sustainability at their core, establish a new paradigm of water conservancy support that prioritizes ecology and emphasizes high efficiency and energy conservation. This will help China’s water conservancy sector achieve sustainable development and contribute Chinese wisdom to global infrastructure construction, disaster prevention and mitigation, and environmental protection.