高聚物改良砂土强度特性和变形特征试验研究  

Experimental study on strength and deformation characteristics of polymers treated sand

作　　者：白玉霞 刘瑾[3] 宋泽卓[3] 张晨阳 何承宗 邓永锋 BAI Yuxia;LIU Jin;SONG Zezhuo;ZHANG Chenyang;HE Chengzong;DENG Yongfeng(School of Civil Engineering,Architecture and Environment,Hubei University of Technology,Wuhan 430068,China;Key Laboratory of Intelligent Health Perception and Ecological Restoration of River and Lake,Ministry of Education,Hubei University of Technology,Wuhan 430068,China;School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China)

机构地区：[1]湖北工业大学土木建筑与环境学院,武汉430068 [2]湖北工业大学河湖健康智慧感知与生态修复教育部重点实验室,武汉430068 [3]河海大学地球科学与工程学院,南京211100

出　　处：《复合材料学报》2024年第8期4272-4286,共15页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(52208339,U22A20232);河湖健康智慧感知与生态修复教育部重点实验室开放研究基金(HGKFZP007);江苏省水利科技项目重大技术攻关资助项目(2017010)。

摘　　要：基于高聚物加固砂土展开抗剪和抗压试验,分析了高聚物掺量、养护时间和干密度对加固砂土强度和变形特征的影响,并阐明其相关性,最后结合SEM图像揭示了高聚物加固砂土的破坏机制。结果表明:(1)3个研究变量对加固砂土抗压和抗剪强度有显著促进作用,其中高聚物含量和养护时间对抗剪强度的影响主要体现在黏聚力上,并且强度与养护时间强正相关,与高聚物含量和干密度中等正相关,可用对数函数(或线性函数)表示其关系;(2)3个研究变量增加时,试样剪切特征由剪切硬化型转变为剪切软化型、破坏位移逐渐减小(干密度减小时),轴向应力-应变曲线表现明显的峰后缓和现象并产生明显的变化,破坏模式以鼓胀并伴有裂缝为主,形态由E型逐渐变为G型(干密度减小时);(3)加固砂土变形特征与养护时间强正相关,与干密度中等负相关,而与高聚物含量相关性不显著,峰值应变与3个研究变量呈多项式(或线性)关系;(4)对于高聚物加固砂土,最佳掺量为约2%,养护24 h及以上时效果显著;(5)高聚物通过吸附、粘结和填充作用在砂粒间形成有效稳定的三维网状膜结构,从而改良砂土微观结构,高聚物在荷载下的变化类型占比决定了加固砂土的变形能力和破坏模式,而这与高聚物掺量、养护时间和干密度密切相关。Polymer has broad application prospects in soil stabilization.However,there is currently little research on the strength and deformation characteristics of polymer treated soil,as well as the degree of influence of different influencing factors.In this work,a series of unconfined compression strength and shear strength tests were performed on a water-soluble polymer treated sand,and subsequently,the effects of polymer content,curing time and dry density on the strength and deformation characteristics of the treated sand were analyzed.Also,the degree of influence of the three research variables was elucidated using correlation analysis.And finally,the related mechanism of treated sand was revealed using SEM observations.The results show that:(1)The three studied variables significantly enhance the unconfined compression strength and shear strength,and the influence of polymer content and curing time on shear strength was mainly reflected in the cohesion.The strength of polymer treated sand is significantly and positively correlated with curing time,and moderately and positively correlated with polymer content and dry density.In addition,these relationships can be represented by a logarithmic function or linear function.(2)As the polymer content,curing time and dry density increase,the shear characteristics of treated sand change from shear hardening type to shear softening type,and the shear failure displacement of treated sand decreases gradually(as dry densities decreases).Also,its axial stress-strain curve shows obvious post-peak easing phenomenon and then produces obvious changes,and the compression failure pattern is dominated by bulging and accompanied by cracks,what's more,this pattern gradually changes from E-type to G-type(as dry densities decreases).(3)The deformation capacity of treated sand is strongly and positively correlated with curing time,moderately and positively correlated with dry density,while the correlation with polymer content is not significant.Additionally,the peak strain has a polynomia

关 键 词：高聚物 砂土 强度特性 变形特征 相关性分析 微观机制 

分 类 号：TU443[建筑科学—岩土工程] TB332[建筑科学—土工工程]