Engineering properties of biodegradable vertical drains for soft ground improvement

The vertical drainage consolidation method is widely employed for soft ground improvement, traditionally using prefabricated plastic vertical drains (PPVDs) to facilitate effective pore water discharge. However, the non-biodegradable nature of PPVDs poses environmental challenges and complicates subsequent construction activities. To address these issues, natural prefabricated vertical drains (NPVDs) and prefabricated straw vertical drains (PSVDs) have emerged as sustainable alternatives. This study reviews the chemical composition, discharge capacity, tensile strength, and biodegradability of PPVDs, NPVDs, and PSVDs. The results demonstrate that PSVDs exhibit superior drainage performance due to their robust rectangular channels, while NPVDs degrade more rapidly under microbial and chemical influences. Although biodegradation benefits the environment, there is an associated decline in drainage efficiency. However, the field test shows that the degradation of NPVD and PSVD has no significant effect on soil consolidation. Future research should prioritize material optimization to balance biodegradability and durability, conduct long-term performance evaluations under varying environmental conditions, and integrate numerical simulations with field monitoring to predict the lifespan and effectiveness of NPVDs and PSVDs in practical applications. These findings underscore the potential of biodegradable drains as a sustainable solution for soft ground improvement while addressing critical challenges in material performance and environmental impact.