全固废材料固化硫酸盐渍土的抗压性能研究  

Research on compressive properties of solidified sulfate saline soil with solid waste materials

作　　者：马桂平 MA Guiping(Ningxia Ningdong Railway Co.,Ltd.,Yinchuan 750021,Ningxia,China)

机构地区：[1]宁夏宁东铁路有限公司,宁夏银川750021

出　　处：《工程建设》2025年第3期1-7,共7页Engineering Construction

摘　　要：宁夏地区硫酸盐渍土路基工程在季节性冻融作用下很容易发生盐冻胀破坏,进而导致强度降低。为此,文章开展基于冻融循环下固化硫酸盐渍土的抗压性能研究,以冻融循环次数、氯硫比、粉煤灰掺量、电石渣掺量及硅灰掺量为5个影响因素,通过5因素4水平正交试验设计和无侧限抗压强度试验及XRD衍射试验,得到不同龄期下固化硫酸盐渍土冻融后的抗压强度及反应产物。试验结果表明:1)7、28 d龄期中各因素对固化硫酸盐渍土无侧限抗压强度的影响主次顺序:硅灰掺量>电石渣掺量>冻融循环次数>氯硫比>粉煤灰掺量,且硅灰掺量对强度的影响显著。2)7 d抗冻融效果最佳的设计配比:冻融循环次数为3次,氯硫比为0.1,粉煤灰掺量为15%,电石渣掺量为8%,硅灰掺量为7%,此时抗压强度为5.20 MPa;28 d抗冻融效果最佳设计配比:冻融循环次数为3次,氯硫比为0.1,粉煤灰掺量为25%,电石渣掺量为8%,硅灰掺量为7%,此时抗压强度为7.32 MPa。3)在3种固废材料的协同作用下,生成了水化硅酸钙(C-S-H)、水化铝酸钙(C-A-H)、钙矾石(AFt)以及硫酸钙(CaSO_(4))等胶凝物质,这些物质与土骨架相互连结填充构成稳定牢固的空间网状架构,促使土体强度整体提升。Under the seasonal freeze-thawing action of sulfate saline soil subgrade engineering in Ningxia,it is easy to cause salt freezing and swelling damage,which leads to a decrease in strength.Therefore,based on the research of the compressive properties of solidified sulfate saline soil under freeze-thaw cycles,the compressive strength and reaction products of solidified sulfate saline soil at different ages are obtained based on five influencing factors:the number of freeze-thaw cycles,chlorine-sulfur ratio,fly ash content,calcium carbide slag content and silica fume content,through the 5-factor 4-level orthogonal test design and unconfined compressive strength test and XRD diffraction test.The test results show that:1)The effects of various factors on the unconfined compressive strength of solidified sulfate saline soil in 7~28 d are silica fume content>calcium carbide slag content>freeze-thaw cycle number>chloride-sulfur ratio>fly ash content,and the effect of silica fume content on the strength is significant.2)The design ratio with the best freeze-thaw resistance effect for 7 d is as follows:the number of freeze-thaw cycles is 3 times,the chlorine-sulfur ratio is 0.1,the fly ash content is 15%,the calcium carbide slag content is 8%,the silica fume content is 7%,and the compressive strength is 5.20 MPa.The optimal design ratio of freeze-thaw resistance in 28 d is as follows:the number of freeze-thaw cycles is 3 times,the chlorine-sulfur ratio is 0.1,the fly ash content is 25%,the calcium carbide slag content is 8%,the silica fume content is 7%,and the compressive strength is 7.32 MPa.3)Under the synergistic effect of three solid waste materials,cementitious substances such as calcium silicate hydrate(C-S-H),calcium aluminate hydrate(C-A-H),calcite(AFt)and calcium sulfate(CaSO_(4))are generated,which are interconnected with the soil skeleton to form a stable and solid spatial network structure,which promotes the overall improvement of soil body strength.

关 键 词：硫酸盐渍土 全固废材料 冻融循环 抗压强度 衍射分析 

分 类 号：TU448[建筑科学—岩土工程]