二灰改良黄河下游沉积泥沙的路用性能

Road Performance of Lime-Fly Ash Stabilized Sedimentary Silt in the Lower Reaches of the Yellow River

摘要:

为探索黄河下游沉积泥沙在路基工程中的应用，以石灰和粉煤灰对其进行改良，同时结合回弹模量测试、直剪试验和极限承载能力计算，对二灰改良黄河泥沙的路用性能进行分析。结果表明：当粉煤灰掺量大于40%时，无论石灰掺量数值如何，二灰改良黄河泥沙的回弹模量符合规范JTG 3441—2024《公路工程无机结合料稳定材料试验规程》要求，但抗剪强度指标提升效果有限；当石灰掺量大于4%时，二灰改良黄河泥沙较石灰掺量小于4%时的回弹模量显著提高，但抗剪强度指标改善有所减缓。综合考量极限承载力、时效性及成本效益，最终确定4%石灰+40%粉煤灰的掺量及7 d养护龄期为黄河泥沙的最佳改良方案。

Abstract:

To explore the application of sediment silt in the lower reaches of the Yellow River in roadbase engineering， lime and fly ash were used to improve its properties. Resilient modulus test， direct shear test， and ultimate bearing capacity calculation were conducted to analyze the road performance of the sediment modified by these two materials. The results show that when the fly ash blending ratio exceeds 40%， regardless of the lime content value， the resilient modulus of binary ash improved Yellow River sedimentary silt meets the control requirements of specification JTG 3441—2024 Test Procedures for Stabilized Materials with Inorganic Binders in Highway Engineering， but the effect on improving the anti-shear strength index is limited. However， when the lime content exceeds 4%， the resilient modulus of the two-material-modified Yellow River sediment silt significantly increases compared to when the lime content is less than 4%， although the improvement in shear strength indices slows down. Considering ultimate bearing capacity， time-effectiveness， and cost-benefit analysis， the optimal improvement scheme for Yellow River sediment silt is determined to be a combination of 4% lime and 40% fly ash with a curing age of 7 days.