PDF全文阅读

姜龙飞 , 高晓俊

 

(云南建设基础设施投资股份有限公司 , 昆明   650000)

摘  要: 为确定粉煤灰—水泥复合改良软土的适宜配比 , 设置不同水泥掺量和不同粉煤灰掺量 , 构建 3× 4双因素配比试验 , 并设置未改良土 、单掺水泥和单掺粉煤灰对照组 。通过无侧限抗压 、压缩 、CBR、抗渗和干湿循环试验 , 结合双因素方差分析 、SEM/XRD 测试及现场沉降监测 , 评价改良土的力学性能 、耐久性和变形控制效果 。结果表明 : 水泥掺量 、粉煤灰掺量及二者交互作用均显著影响改良土性能 ; 粉煤灰掺量由 10%增至 20%时 , 各项性能持续改善 , 增至 25%后有所下降 。5%水泥与 20%粉煤灰组合的 28 d 无侧限抗压强度为 1. 31 MPa,压缩模量为 8. 15 MPa, 2. 5 mm 贯入量下 CBR 值为 17. 4% , 7 次干湿循环后强度保持率为 86. 8%。现场一般改良段 120 d 累计沉降量较未改良段降低 53. 9%。综合性能和材料用量 , 5%水泥与 20%粉煤灰为较适宜配比 。研究成果可为相关工程提供参考。

关键词: 粉煤灰 ; 道桥施工 ; 软基加固 ; 无侧限抗压强度 ; 沉降控制

中图分类号: U416. 1      文献标志码: A      文章编号: 1005-8249 (2026) 05-0034-09

DOI:10. 19860/j. cnki. issn1005-8249. 2026. 05. 006

 

JIANG Longfei , GAO Xiaojun

(Yunnan Infrastructure Investment Co. , Ltd. , Kunming 650000, China)

Abstract : To determine the appropriate ratio of fly ash-mixed cement for improving soft soil, three cement contents of 4% , 5% , and 6% and four fly ash contents of 10% , 15% , 20% , and 25% were set. A 3× 4 two-factor ratio test was constructed, and control groups without improvement, single cement addition, and single fly ash addition were also set. Through unconfined compressive strength, compression, CBR, impermeability, and dry-wet cycle tests, combined with two-factor variance analysis, SEM/XRD tests, and on-site settlement monitoring, the mechanical properties, durability, and deformation control effects of the improved soil were evaluated. The results showed that the cement content, fly ash content, and their interaction all significantly affected the performance of the improved soil; when the fly ash content increased from 10% to 20% , all performance indicators continued to improve, and decreased after increasing to 25%. The 28-day unconfined compressive strength of the 5% cement and 20% fly ash combination was 1. 31 MPa, the compression modulus was 8. 15 MPa, the CBR value at a 2. 5 mm penetration was 17. 4% , and the strength retention rate after 7 dry-wet cycles was 86. 8%.  The cumulative settlement of the improved section in the field was 53. 9% lower than that of the unimproved section. Considering the comprehensive performance and material usage, a 5% cement and 20% fly ash combination was found to be the more suitable ratio. The findings may serve as a reference for related engineering practices.

Key words: fly ash; road and bridge construction; soft soil reinforcement; unconfined compressive strength; settlement control

作者简介 : 姜龙飞 (1988—) , 男, 本科, 高级工程师, 研究方向 : 工程管理、高速公路。