摘要
为克服粉土强度低、干湿循环性能差的特点,同时解决固体废弃物木质素的资源化利用的问题,将木质素掺入粉土中,形成木质素改良粉土。为研究木质素改良粉土抗剪强度特性及干湿循环性能,对经历干湿循环后的木质素改良粉土进行直接剪切试验和X射线衍射试验,研究了木质素掺量0、2%、5%、8%、12%、15%和干湿循环0、1、2、3、4次对改良土抗剪强度特性的影响。结果表明:掺入木质素可以显著提升粉土的抗剪强度及干湿循环性能;一定干湿循环次数下,改良土的抗剪强度及黏聚力随着木质素掺量的增加先增大后降低,内摩擦角随着木质素掺量的增加先快速增大后基本不变;当木质素掺量为8%时,改良土的抗剪强度、黏聚力和内摩擦角最高。改良土的抗剪强度、黏聚力和内摩擦角均随着干湿循环次数的增加而降低,当木质素掺量为0时,纯土试样经过1次干湿循环即崩解,强度损失率为100%;当木质素掺量为8%时,改良土的强度损失率最低,黏聚力及内摩擦角的降低幅度均较低。X射线衍射试验表明,木质素掺量为8%时,石英、方解石、白云石含量最高,黏土矿物含量较高,钠长石含量最低,这是造成改良土强度及干湿循环性能提升的直接原因。结果显示,当木质素掺量为8%时,改良土在提高抗剪强度及干湿循环性能方面具有明显优势。研究结果可为实际施工设计提供理论支撑。
By adding lignin into silty soil,a new lignin-modified silty soil was proposed to overcome the disadvantages of silty soil such as low strength and poor dry-wet cycle performance,and to solve the problem of resource utilization of solid waste lignin.In order to study the shear strength and dry-wet cycle performance of lignin-modified silty soil,direct shear tests and X-ray diffraction tests were conducted on the modified soil samples with different lignin content after dry-wet cycles.The effects of lignin content 0,2%,5%,8%,12%,15%and dry-wet cycles 0,1,2,3,4 times on the shear strength of lignin-modified silty soil were studied.The experimental results showed that lignin incorporation could signific-antly improve the shear strength and dry-wet cycle resistance of the modified soil.Under a certain number of dry-wet cycles,the shear strength and cohesion of the modified soil increased first and then decreased with the increase of lignin content,and the internal friction angle increased linearly at first and then remained unchanged.The highest shear strength,cohesion and internal friction angle were found when the lignin content was 8%.The shear strength,cohesion and internal friction angle of the modified soil decreased with the increase of the number of dry-wet cycles.When lignin content was 8%,the strength loss rate of the modified soil after dry-wet cycles was the lowest.When the lignin content was 8%,the content of quartz,calcite and dolomite was the highest,the content of clay minerals was higher,and the content of albite was the lowest,which was the direct cause for improving the strength of modified soil and its dry-wet cycle performance.The results showed that when lignin content was 8%,the modified soil had obvious advantages in improving shear strength and dry-wet cycle performance.
作者
周恩全
张曼
居东煜
王龙
李护良
ZHOU Enquan;ZHANG Man;JU Dongyu;WANG Long;LI Huliang(Faculty of Civil Eng.and Mechanics,Jiangsu Univ.,Zhenjiang 212013,China;Faculty of Environment and Civil Eng.,Jiangnan Univ.,Wuxi 214122,China)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2024年第2期208-216,共9页
Advanced Engineering Sciences
基金
江苏省自然科学基金项目(BK20210479)
南京市交通运输科技项目(2022)。
关键词
木质素
粉土
干湿循坏
抗剪强度
lignin
silty soil
dry-wet cycle
shear strength
