摘要
粉煤灰是燃煤行业产生的细颗粒固废,宁夏地区粉煤灰利用率低于全国平均水平,有效处理是当前亟须解决的问题。随着大量公路建设路堤填料需求的不断增加,将粉煤灰作为路堤填料既是固废利用又是对天然填料的补充。交通荷载下路堤的强度和变形是衡量填料力学性能的重要指标。以宁夏某电厂粉煤灰作为路堤填料,开展养护7~28 d的无侧限抗压强度、静三轴和养护7 d的动三轴试验,探索粉煤灰在静力、交通荷载下的特性及其作为路堤填料的可行性。结果显示:随着养护龄期增长,粉煤灰静态承载力增大;粉煤灰累积塑性应变与振动次数和动应力幅值呈正相关,Monismith指数模型能较好地反映粉煤灰塑性应变随振动次数的关系,Hardin双曲线模型可以拟合粉煤灰动应力-动应变的关系;粉煤灰静动力特性介于黄土和砂土之间,是一种承载性能良好的高速公路路堤填料,可为固废粉煤灰在道路工程中的普遍应用提供数据支撑。
Fly ash is a fine particulate solid waste produced by the coal industry.Using fly ash as embankment filler not only helps address the challenge of solid waste disposal but also provides a sustainable alternative to natural fillers.Fly ash sourced from a power plant in Ningxia was utilized to assess its suitability as an embankment filler.The study involved a series of tests,including unconfined compressive strength tests and static triaxial tests conducted over curing periods ranging from 7 to 28 days,as well as a dynamic triaxial test performed after 7 days of curing.The results indicate that the fly ash exhibits an enhanced static bearing capacity with increasing curing age.This improvement is attributed to the formation of hydrated calcium silicate during the curing process,which serves as a cementing and filling agent.The cumulative plastic strain of fly ash shows a positive correlation with the number of vibrations and the amplitude of dynamic stress.The curve of cumulative plastic strain exhibits two distinct patterns:failure and stability.The dynamic extreme stress value increases with the confining pressure.The dynamic backbone curve flattens as dynamic stress increases.Additionally,the dynamic elastic modulus decreases,while the damping ratio increases with the rise in dynamic strain.The Monismith index model effectively captures the relationship between the plastic strain of fly ash and the number of vibrations,while the Hardin hyperbolic model accurately describes the relationship between dynamic stress and dynamic strain in fly ash.Both models can serve as valuable references for calculating embankment deformation.The static and dynamic characteristics of fly ash are found to be superior to those of loess but inferior to those of sand.As a highway embankment filler,fly ash demonstrates excellent bearing performance,providing valuable data to support the application of solid waste fly ash in road engineering.
作者
董旭光
刘天
马文国
颉永斌
惠迎新
DONG Xuguang;LIU Tian;MA Wenguo;XIE Yongbin;HUI Yingxin(School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China;School of Civil Engineering,Tianshui Normal University,Tianshui 741000,Gansu,China)
出处
《安全与环境学报》
北大核心
2025年第7期2791-2801,共11页
Journal of Safety and Environment
基金
宁夏自然科学基金项目(2023AAC03038)
国家自然科学基金项目(52368050,51968061)
宁夏大学水利工程一流学科项目(NXYLXK2021A03)。
关键词
环境工程学
粉煤灰
路堤
静力特性
动力特性
动应力极值
environmental engineering
fly ash
roadbed
static characteristic
dynamic characteristic
dynamic extreme stress
