Soft clay treatment with all industrial by-product(IBP)binder has great economic and environmental benefits,yet its geomechanics and mechanisms still need to be well probed.With the activation by calcium carbide resid...Soft clay treatment with all industrial by-product(IBP)binder has great economic and environmental benefits,yet its geomechanics and mechanisms still need to be well probed.With the activation by calcium carbide residue(CCR)and phosphogypsum(PG),the strength,structure,and mechanisms of soft clay treated by aluminosilicate-rich IBP(AS-IBP,such as ground granulated blast furnace slag(GGBS),fly ash(FA),coal gangue(CG),Bayer red mud(BR),and sintered red mud(SR))are comparatively investigated.The strength characteristics of solidified clay exhibit significant differences as AS-IBP changes.When GGBS is adopted,the strength is sensitive to the change in PG content,while the impact of CCR is insignificant.After 90 d,the strength of the optimal sample(G23)reaches 1.40 MPa,35.9%higher than cement solidified clay(CSC),while that achieved by other AS-IBPs is less than 0.3 MPa.In the compression test,the structure's evolutionary trend of G23 has a sudden change as the strength increases from 1.81 MPa to 2.29 MPa,suggesting the transformation in material properties.Besides,the structure of G23 is stronger than CSC,which contributes more to the compressive performance.The total amount of main products(C-S-H and ettringite)of all-IBP solidified clay determines the strength,and ettringite is only significant when calcium-rich AS-IBP is adopted.The total amount of minor products(C-A-H and C-A-S-H)is similar for different samples,equivalent to 28.9%-46.3%of the main products.The relationship between the strength and the product amount can be presented using an exponential function.展开更多
黏土的触变性是指黏土受扰动后强度降低,静置之后强度逐渐恢复的现象,这种特殊的力学性质对工程建筑地基的承载力和稳定性有较为显著的影响。为了研究湛江组结构性黏土的触变特性及其微观结构演化特征,通过对不同初始含水率的重塑湛江...黏土的触变性是指黏土受扰动后强度降低,静置之后强度逐渐恢复的现象,这种特殊的力学性质对工程建筑地基的承载力和稳定性有较为显著的影响。为了研究湛江组结构性黏土的触变特性及其微观结构演化特征,通过对不同初始含水率的重塑湛江组结构性黏土,采用无侧限抗压强度试验、扫描电镜(scanning electron microscopy,SEM)试验和核磁共振(nuclear magnetic resonance,NMR)试验,开展不同养护龄期下的试验分析。研究表明,湛江组结构性黏土的触变强度比率(A_(t))随养护龄期的增长而增大,具体可分为3个阶段:触变强度比率迅速增大(触变性强)、增长速率减缓(触变性减弱)及趋于稳定(触变性逐渐消失)。土体在触变过程中,土颗粒之间的连接越来越牢固稳定,土颗粒骨架间的孔隙也随之定向排列有序性不断增强,孔隙形态趋于规则,土体整体微观结构从松散的絮凝结构向蜂窝—紧密絮凝状结构演化,越来越均质紧密。通过对触变强度比率和基于SEM图像提取的微观结构参数进行灰色关联分析可知:分形维数、概率熵和扁圆度与触变强度比率均具有明显的相关性,概率熵与土体的触变性强度比率相关性最高、其次为分形维数、最后是扁圆度,因此,应首选概率熵表征土体触变性变化规律,次选分形维数、扁圆度。展开更多
为探究酸污染下老黏土的工程特性演变规律,文章配制3种不同pH值的酸性溶液对老黏土进行持续浸泡试验,系统开展比重、自由膨胀率、直剪、液塑限、粒度分析等室内土工试验,并利用扫描电子显微镜(scanning electron microscope,SEM)、X射...为探究酸污染下老黏土的工程特性演变规律,文章配制3种不同pH值的酸性溶液对老黏土进行持续浸泡试验,系统开展比重、自由膨胀率、直剪、液塑限、粒度分析等室内土工试验,并利用扫描电子显微镜(scanning electron microscope,SEM)、X射线衍射仪(X-ray diffractometer,XRD)对土体微观结构及物质组成进行分析,从微观角度研究酸污染下老黏土工程特性演变规律。试验结果表明:在酸溶液的浸泡下,老黏土内部矿物不断溶蚀,土颗粒粒径减小,比表面积增加,微观结构变得松散、破碎,土体的比重、黏聚力、压缩模量、液塑限等工程指标数值下降,内摩擦角基本不变,自由膨胀率及渗透系数得到提高。基于试验结果,探究了酸污染下老黏土工程特性的演变机理,建立了老黏土抗剪强度、压缩模量、渗透系数、自由膨胀率的工程特性指标变化率随浸泡溶液pH值变化的数理模型,指出用黏聚力、压缩模量、渗透系数对酸污染后老黏土的污染等级进行评价较为合理。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.U24A20183)Natural Science Fund for Distinguished Young Scholars of Hubei Province,China(Grant No.2024AFA051)Youth Science Fund(A-class)of Hunan Natural Science Foundation of China(Grant No.2025JJ20049).
文摘Soft clay treatment with all industrial by-product(IBP)binder has great economic and environmental benefits,yet its geomechanics and mechanisms still need to be well probed.With the activation by calcium carbide residue(CCR)and phosphogypsum(PG),the strength,structure,and mechanisms of soft clay treated by aluminosilicate-rich IBP(AS-IBP,such as ground granulated blast furnace slag(GGBS),fly ash(FA),coal gangue(CG),Bayer red mud(BR),and sintered red mud(SR))are comparatively investigated.The strength characteristics of solidified clay exhibit significant differences as AS-IBP changes.When GGBS is adopted,the strength is sensitive to the change in PG content,while the impact of CCR is insignificant.After 90 d,the strength of the optimal sample(G23)reaches 1.40 MPa,35.9%higher than cement solidified clay(CSC),while that achieved by other AS-IBPs is less than 0.3 MPa.In the compression test,the structure's evolutionary trend of G23 has a sudden change as the strength increases from 1.81 MPa to 2.29 MPa,suggesting the transformation in material properties.Besides,the structure of G23 is stronger than CSC,which contributes more to the compressive performance.The total amount of main products(C-S-H and ettringite)of all-IBP solidified clay determines the strength,and ettringite is only significant when calcium-rich AS-IBP is adopted.The total amount of minor products(C-A-H and C-A-S-H)is similar for different samples,equivalent to 28.9%-46.3%of the main products.The relationship between the strength and the product amount can be presented using an exponential function.
文摘黏土的触变性是指黏土受扰动后强度降低,静置之后强度逐渐恢复的现象,这种特殊的力学性质对工程建筑地基的承载力和稳定性有较为显著的影响。为了研究湛江组结构性黏土的触变特性及其微观结构演化特征,通过对不同初始含水率的重塑湛江组结构性黏土,采用无侧限抗压强度试验、扫描电镜(scanning electron microscopy,SEM)试验和核磁共振(nuclear magnetic resonance,NMR)试验,开展不同养护龄期下的试验分析。研究表明,湛江组结构性黏土的触变强度比率(A_(t))随养护龄期的增长而增大,具体可分为3个阶段:触变强度比率迅速增大(触变性强)、增长速率减缓(触变性减弱)及趋于稳定(触变性逐渐消失)。土体在触变过程中,土颗粒之间的连接越来越牢固稳定,土颗粒骨架间的孔隙也随之定向排列有序性不断增强,孔隙形态趋于规则,土体整体微观结构从松散的絮凝结构向蜂窝—紧密絮凝状结构演化,越来越均质紧密。通过对触变强度比率和基于SEM图像提取的微观结构参数进行灰色关联分析可知:分形维数、概率熵和扁圆度与触变强度比率均具有明显的相关性,概率熵与土体的触变性强度比率相关性最高、其次为分形维数、最后是扁圆度,因此,应首选概率熵表征土体触变性变化规律,次选分形维数、扁圆度。
文摘为探究酸污染下老黏土的工程特性演变规律,文章配制3种不同pH值的酸性溶液对老黏土进行持续浸泡试验,系统开展比重、自由膨胀率、直剪、液塑限、粒度分析等室内土工试验,并利用扫描电子显微镜(scanning electron microscope,SEM)、X射线衍射仪(X-ray diffractometer,XRD)对土体微观结构及物质组成进行分析,从微观角度研究酸污染下老黏土工程特性演变规律。试验结果表明:在酸溶液的浸泡下,老黏土内部矿物不断溶蚀,土颗粒粒径减小,比表面积增加,微观结构变得松散、破碎,土体的比重、黏聚力、压缩模量、液塑限等工程指标数值下降,内摩擦角基本不变,自由膨胀率及渗透系数得到提高。基于试验结果,探究了酸污染下老黏土工程特性的演变机理,建立了老黏土抗剪强度、压缩模量、渗透系数、自由膨胀率的工程特性指标变化率随浸泡溶液pH值变化的数理模型,指出用黏聚力、压缩模量、渗透系数对酸污染后老黏土的污染等级进行评价较为合理。
