木质素改良粉土临界状态剪切特性试验
发布时间：2019-06-25 17:09
【摘要】：为了使工业副产品木质素在粉土路基中得到更好的应用,采用室内无侧限抗压强度试验、三轴压缩试验和扫描电镜试验,研究木质素改良粉土的剪切强度特性和微观结构,分析木质素掺量、养护龄期对改良土强度和破坏特征的影响,探讨不同围压和排水剪切条件下改良土的应力-应变关系,阐述木质素产生的胶结作用对土体剪切特性的影响,并研究临界状态下改良土的剪切强度特征。试验结果表明:改良土体无侧限抗压强度随木质素掺量增加而增加,过高掺量会造成强度降低,木质素的添加可增强粉土的韧性特征,对于江苏粉土的木质素最优掺入质量分数为12%;终值偏应力随围压和掺量增加而增大,其增量随围压增加呈降低趋势;低围压条件下,剪切过程会产生吸力,改良土孔隙水压力在各围压下均小于素土;低围压排水剪切条件下,改良土体积应变存在先"剪缩"后"剪胀"的变化特征,高围压条件下则完全表现为"剪缩";木质素产生的胶结物质填充孔隙并增强土颗粒间联结,土体形成更为致密、稳定的微观结构;改良土临界状态线相对于素土仅发生平移,黏聚力可用来表征木质素对土体临界状态强度特性的影响;临界状态下木质素改良土剪切特性的研究可为其本构模型建立提供一定的基础。
[Abstract]:In order to make the industrial byproduct lignin be better used in silt subgrade, the shear strength characteristics and microstructure of lignin modified silt were studied by laboratory unconfined compressive strength test, triaxial compression test and scanning electron microscope test, the effects of lignin content and curing age on the strength and failure characteristics of improved soil were analyzed, and the stress-strain relationship of improved soil under different confining pressure and drainage shear conditions was discussed. The effect of lignin bonding on the shear properties of soil is described, and the shear strength characteristics of improved soil in critical state are studied. The results show that the unconfined compressive strength of the improved soil increases with the increase of lignin content, and the strength decreases with the increase of lignin content. The addition of lignin can enhance the toughness characteristics of silt. For Jiangsu silt, the optimal lignin content is 12%, and the final bias stress increases with the increase of confining pressure and content, and the increment decreases with the increase of confining pressure. Under the condition of low confining pressure, the suction will be produced in the shear process, and the pore water pressure of the improved soil is less than that of the plain soil under each confining pressure. Under the condition of low confining pressure drainage shear, the volume strain of the improved soil has the characteristics of "shear shrinkage" first and then "shear expansion", while under the condition of high confining pressure, the cementitious material produced by lignin fills the pores and strengthens the connection between soil particles, and the soil forms a more compact and stable microstructure. The critical state line of improved soil is only shifted relative to plain soil, and the cohesion can be used to characterize the effect of lignin on the critical state strength characteristics of soil, and the study of shear characteristics of lignin modified soil in critical state can provide a certain basis for the establishment of its constitutive model.
【作者单位】： 中国地质大学(武汉)工程学院;东南大学交通学院;
【基金】：国家自然科学基金项目(41330641,41202203) 高等学校全国优秀博士学位论文作者专项资金项目(201353) 教育部新世纪优秀人才支持计划项目(NCET-13-0118) 中央高校基本科研业务费专项资金项目(2242013R30014) 江苏省杰出青年基金项目(BK20140027) 江苏省交通科学研究计划项目(2013Y04)
【分类号】：U416.1
本文编号：2505850
[Abstract]:In order to make the industrial byproduct lignin be better used in silt subgrade, the shear strength characteristics and microstructure of lignin modified silt were studied by laboratory unconfined compressive strength test, triaxial compression test and scanning electron microscope test, the effects of lignin content and curing age on the strength and failure characteristics of improved soil were analyzed, and the stress-strain relationship of improved soil under different confining pressure and drainage shear conditions was discussed. The effect of lignin bonding on the shear properties of soil is described, and the shear strength characteristics of improved soil in critical state are studied. The results show that the unconfined compressive strength of the improved soil increases with the increase of lignin content, and the strength decreases with the increase of lignin content. The addition of lignin can enhance the toughness characteristics of silt. For Jiangsu silt, the optimal lignin content is 12%, and the final bias stress increases with the increase of confining pressure and content, and the increment decreases with the increase of confining pressure. Under the condition of low confining pressure, the suction will be produced in the shear process, and the pore water pressure of the improved soil is less than that of the plain soil under each confining pressure. Under the condition of low confining pressure drainage shear, the volume strain of the improved soil has the characteristics of "shear shrinkage" first and then "shear expansion", while under the condition of high confining pressure, the cementitious material produced by lignin fills the pores and strengthens the connection between soil particles, and the soil forms a more compact and stable microstructure. The critical state line of improved soil is only shifted relative to plain soil, and the cohesion can be used to characterize the effect of lignin on the critical state strength characteristics of soil, and the study of shear characteristics of lignin modified soil in critical state can provide a certain basis for the establishment of its constitutive model.
【作者单位】： 中国地质大学(武汉)工程学院;东南大学交通学院;
【基金】：国家自然科学基金项目(41330641,41202203) 高等学校全国优秀博士学位论文作者专项资金项目(201353) 教育部新世纪优秀人才支持计划项目(NCET-13-0118) 中央高校基本科研业务费专项资金项目(2242013R30014) 江苏省杰出青年基金项目(BK20140027) 江苏省交通科学研究计划项目(2013Y04)
【分类号】：U416.1
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，本文编号：2505850
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