木质素改良粉土热学与力学特性相关性试验研究

发布时间：2018-09-03 12:20

【摘要】：为揭示木质素改良粉土热学与力学特性随养护龄期的演化规律,通过击实试验、热阻系数测试、无侧限抗压强度试验、回弹模量试验、压汞试验和扫描电镜分析试验,探讨改良土热阻系数、强度和刚度与木质素掺量、含水率和养护龄期的变化规律,同时定性/定量评价改良土微观结构变化,分析改良土热学特性与力学特性间的相互关系。结果表明:改良土最大干密度较素土增加,最优含水率减小,干密度对含水率变化的敏感性增加;热阻系数随掺量和养护龄期增加而增加,60 d养护龄期后热阻系数趋于相同,热阻系数与土体密实度和组成成分的热传导特性密切相关;改良土强度随掺量和龄期增长而增加,28 d龄期12%掺量改良土强度约为素土强度6倍;回弹模量的变化特征与无侧限抗压强度类似,对于改良粉土,木质素最优掺量约为12%;改良土孔隙总体积和平均孔径显著减小,木质素包裹、连结土颗粒并填充孔隙,形成更致密土体结构。
[Abstract]:In order to reveal the evolution of thermal and mechanical properties of lignin modified silt with curing age, compaction test, thermal resistance coefficient test, unconfined compressive strength test, elastic modulus test, mercury injection test and scanning electron microscope analysis test were used. The changes of thermal resistance coefficient, strength and stiffness of improved soil with lignin content, moisture content and curing age were discussed. The microstructure of improved soil was evaluated qualitatively / quantitatively, and the relationship between thermal and mechanical properties of improved soil was analyzed. The results show that the maximum dry density of the improved soil is higher than that of the plain soil, the optimum moisture content decreases, and the sensitivity of the dry density to the change of moisture content increases, and the thermal resistance coefficient tends to be the same after the increase of 60 d curing age with the increase of the content and curing age of the improved soil. The thermal resistance coefficient is closely related to the compactness of soil and the heat conduction characteristics of the composition, and the strength of the improved soil increases with the increase of the content and age of the soil, and the strength of the modified soil at 28 d age is about 6 times as much as that of the plain soil. The variation of resilience modulus is similar to that of unconfined compressive strength. For improved silt, the optimum content of lignin is about 12%. The total pore volume and average pore size of the improved soil are significantly reduced, and lignin is wrapped around the soil particles and filled with pores. Forming a more compact soil structure.
【作者单位】：东南大学岩土工程研究所;江苏省城市地下工程与环境安全重点实验室;江苏省交通规划设计院股份有限公司;
【基金】：国家自然科学基金项目(41330641,41202203) 全国优秀博士学位论文作者专项资金项目(201353) 江苏省杰出青年基金项目(BK20140027) 教育部新世纪优秀人才支持计划(NCET-13-0118) 中央高校基本科研业务费资助项目(2242013R30014) 江苏省交通科学研究计划项目(2013Y04)
【分类号】：TU43

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