生物炭改性双层基质绿色屋顶水力特性研究

Study on hydraulic properties of biochar-modified bilayer substrate green roofs

摘要

【目的】城市快速发展导致洪涝和热岛效应加剧，绿色屋顶可缓解这些问题，特别是其基质层土壤对雨水管理影响很大。使用生物炭改良土壤的双层基质层绿色屋顶能够有效优化雨水管理能力。【方法】采用室内试验和数值模拟相结合，探究双层基质绿色屋顶的水力性能。基于试验柱对人工降雨条件下的水力过程进行了观测，利用反解法估算基质土非饱和水力参数；采用数值模拟探讨生物炭双层基质在雨水管理中的应用效果。【结果】结果显示：不同的生物炭施用方式在延缓和减少峰流方面表现出不同的性能。在选定的暴雨情况下，有3 cm天然土壤和12 cm生物炭处理土壤的双层基质结构有更好的雨水管理能力。【结论】结果表明：用生物炭改良土壤，采用双层基质展示了其在绿色屋顶中的灵活性和高效性。这为屋面绿化设计提供了初步指导，也为优化屋顶绿化暴雨管理提供设计方向，为未来研究奠定了基础。

Abstract

[Objective] Rapid urban development has exacerbated flooding and heat island effects, while green roofs can help mitigate these issues, especially as the substrate soil significantly affects stormwater management. A bilayer substrate green roof with biochar-modified soil can effectively improve rainwater management performance. [Methods] Laboratory experiments and numerical simulations were combined to investigate the hydraulic performance of bilayer substrate green roofs. The hydraulic processes under artificial rainfall conditions were observed using test columns, and the inverse solution method was used to estimate the unsaturated hydraulic parameters of the substrate soil. Numerical simulations were conducted to explore the effectiveness of biochar bilayer substrates in stormwater management. [Results] The result showed that different biochar application method exhibited different performance in delaying and reducing peak flow. Under the selected rainstorm condition, the bilayer substrate structure with 3 cm of natural soil and 12 cm of biochar-modified soil demonstrated better stormwater management performance. [Conclusion] The result indicate that modifying soil with biochar and using a bilayer substrate exhibits flexibility and efficiency in green roofs. This provides preliminary guidance for roof greening design, offers a design direction for optimizing stormwater management in green roofs, and lays the foundation for future research.

关键词

绿色屋顶 / 生物炭 / 改性土 / 雨水管理 / 双层基质 / 水力特性 / 数值模拟

Key words

green roofs / biochar / modified soil / stormwater management / bilayer substrate / hydraulic properties / numerical simulation

基金资助

国家自然科学基金项目“竖向荷载及强降雨耦合作用下粗粒土填料挡墙病害形成机理与防治研究”(52108309)