富有机质淤泥基流态固化土流动性与力学特性研究

Study on fluidity and mechanical properties of organic-matter-rich dredged sediment-based flowable solidified soil

摘要

【目的】传统水泥、石灰等固化材料对富有机质疏浚淤泥的固化效果较差，且淤泥需预先脱水，降低了施工效率。【方法】利用新型固废基胶凝材料协同高锰酸钾用于高含水富有机质淤泥的流动固化处理，以制备流态固化土。通过开展流动度试验和无侧限抗压强度试验，研究高锰酸钾掺量与有机质含量对固化淤泥流动性及无侧限抗压强度的影响。【结果】结果表明：当有机质含量为7%时，固化淤泥流动度随高锰酸钾掺量的增加而增加，其中高锰酸钾掺量为2%和3%时，固化淤泥的流动度(170 mm与204 mm)满足规范要求。在有机质含量为8.5%和10%的情况下，固化淤泥的流动度随高锰酸钾掺量的增加而降低。在高锰酸钾掺量相同的情况下，固化淤泥的无侧限抗压强度随着有机质含量的提高而大幅降低。当有机质含量相同时，随着高锰酸钾掺量从0%增加到1%,固化淤泥的抗压强度大幅下降；继续增加至3%时，固化淤泥抗压强度下降幅度减缓。【结论】有机质和高锰酸钾影响了固废基胶凝材料水化产物的形成，导致固化淤泥的力学性能降低。研究成果可为高含水富有机质淤泥制备流态固化土的工程应用提供理论指导。

Abstract

[Objective] Traditional solidification materials, such as cement and lime, have poor improvement effects on organic-matter-rich dredged sediment, and the sediment needs to be pre-dewatered, which reduces construction efficiency. [Methods] A novel solid waste-based cementitious material, combined with potassium permanganate, were used for the flowable solidification treatment of high-water-content, organic-matter-rich dredged sediment to prepare flowable solidified soil. Flowability tests and unconfined compressive strength(UCS) tests were conducted to investigate the effects of potassium permanganate dosage and organic matter content on the flowability and UCS of solidified sediment. [Results] These findings indicated that when the organic matter content was 7%, flowability of solidified sediment increased with increasing potassium permanganate dosage. At potassium permanganate dosages of 2% and 3%, the flowability of the solidified sediment(170 mm and 204 mm) met the standard requirements. However, when the organic matter content was 8.5% and 10%, the flowability of solidified sediment decreased as potassium permanganate dosage increased. Under the same potassium permanganate dosage, increase in organic matter content significantly reduced UCS of the solidified sediment. When the organic matter content was constant, an increase in potassium permanganate from 0% to 1% resulted in a significant decrease in UCS. Further increases to 3% led to a slower decrease in UCS. [Conclusion] Organic matter and potassium permanganate affect the formation of hydration products of the solid waste-based cementitious material, leading to a reduction in the mechanical properties of the solidified sediment. The research findings provide theoretical guidance for the engineering application of flowable solidified soil made from high-water content, organic-matter-rich sediment.

关键词

地下空区回填 / 疏浚淤泥 / 流态固化土 / 固废基胶凝材料 / 流动度 / 无侧限抗压强度 / 影响因素

Key words

underground space backfilling / dredged sediment / flowable solidified soil / solid waste-based cementitious material / flowability / unconfined compressive strength / influencing factors

基金资助

中交一公局第一工程有限公司立项科研项目(KJYF2024-C-01)

国家自然科学基金项目(52304114)