矿粉固化黄土的力学性能及机理研究  

Research on Mechanical Properties and Solidifying Mechanism of Mineral Powder Solidified Loess

作　　者：陈杰 唐占元 安之焕 高健 马渊博 CHEN Jie;TANG Zhan-yuan;AN Zhi-huan;GAO Jian;MA Yuan-bo(State Grid Qinghai Province Electric Power Company Economic and Technological Research Institute,Xining 81oooo,China;School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]国网青海省电力公司经济技术研究院,西宁市810000 [2]宁夏大学土木与水利工程学院,银川市750021

出　　处：《公路》2025年第3期33-41,共9页Highway

基　　金：宁夏回族自治区重点研发计划项目,项目编号2021BEG03023。

摘　　要：为提高低压缩性黄土力学和耐久性能,采用高活性矿粉改良黄土,并和未固化黄土进行对比。研究了不同矿粉掺量(4%、8%、12%、16%、20%)和养护时间对固化土无侧限抗压强度、水稳定性、剪切特性和冻融耐久性的影响,并通过扫描电镜(SEM)和X射线衍射(XRD)分析了固化土微观结构变化和矿物成分。结果表明,矿粉掺量为16%时,固化土强度最大,28 d无侧限抗压强度达到1235.2 kPa,较未固化土提高了17倍;同时水稳定性最优,水稳性系数为0.74。固化土黏聚力随矿粉掺量增加先增大后减小,内摩擦角整体呈增大趋势。随着冻融循环次数增加,固化土强度整体呈微小增长趋势。微观试验表明,矿粉与部分黄土水化反应生成了较多C-S-H和C-A-H等凝胶体,这些物质通过包裹黄土颗粒、填充孔隙和搭接网络骨架,增大了土颗粒的密实度和颗粒间的黏结性,提高了土体强度。研究成果可为矿粉在黄土路基填筑中的应用提供参考。In order to improve the mechanical and durability properties of low-compressibility loess,the loess is modified with highly active mineral powder modification and compared with unsolidified loess.The effects of different mineral powder contents(4%,8%,12%,16%,20%)and curing time on the unconfined compressive strength,water stability,shear properties and freeze-thaw durability of solidified soil are studied,and the micro-structural changes and mineralogical composition of solidified soil are analyzed by scanning electron microscopy(SEM)and X-ray diffraction(XRD).The results show that the strength of solidified soil is the greatest when the content of mineral powder is 16%,and the 28-day unconfined compressive strength reached 1235.2 kPa,which is 17 times higher than that of the unsolidified soil,the water stability is also optimal,with a water stability coefficient of 0.74.The cohesion of the solidified soil increases and then decreases with the increase of the content of mineral powder,and the angle of internal friction shows a trend of increasing overall.With the increase in the number of freeze-thaw cycles,the overall strength of solidified soil shows a slight growth trend.The microscopic test shows that the hydration reaction between mineral powder and part of loess generates more gels such as C-S-H and CA-H,which increases the compactness of soil particles and the bonding between particles by wrapping the loess particles,filling the pores and lapping the network skeleton,and improves the strength of the soil body.The research results can provide reference for the application of mineral powder in loess subgrade filling.

关 键 词：固化土 黄土地基 矿粉 强度特性 水稳定性 微观机理 

分 类 号：U416.1[交通运输工程—道路与铁道工程] TU444[建筑科学—岩土工程]