基于CT技术的黄原胶加固土干湿循环条件下力学性能和微观结构劣化机制研究  

Deterioration mechanism of mechanical properties and microstructure in xanthan gum-reinforced soil under wetting-drying cycles based on CT scanning technology

作　　者：刘瑾[1] 车文越 郝社锋[2] 马晓凡[1] 喻永祥[2] 王颖 陈志昊 李婉婉 钱卫[1] LIU Jin;CHE Wenyue;HAO Shefeng;MA Xiaofan;YU Yongxiang;WANG Ying;CHEN Zhihao;LI Wanwan;QIAN Wei(School of Earth Sciences and Engineering,Hohai University,Nanjing 211100,China;Technology Innovation Center for Ecological Monitoring&Restoration Project on Land(Arable),Ministry of Natural Resources,Geological Survey of Jiangsu Province,Nanjing 210018,China)

机构地区：[1]河海大学地球科学与工程学院,江苏南京211100 [2]自然资源部国土(耕地)生态监测与修复工程技术创新中心,江苏省地质调查研究院,江苏南京210018

出　　处：《岩土工程学报》2024年第5期1119-1126,共8页Chinese Journal of Geotechnical Engineering

基　　金：自然资源部国土(耕地)生态监测与修复工程技术创新中心开放课题(GTST2021-006);国家重点研发计划(2018YFC1508501)。

摘　　要：干湿循环对岩土体的工程特性具有重要影响。采用CT扫描技术和力学测试,对加入不同含量黄原胶(0%,0.5%,1.5%)加固的黏土在经历不同次数(0,1,4,8,12次)干湿循环作用下的力学性能和微观结构劣化机制进行了研究,得到结论:(1)黄原胶能够有效提高土体的抗压强度和耐干湿循环效果。随着黄原胶含量的增加,干湿循环作用后的强度损失逐渐减小,当循环次数从0次增加到4次时,对于加入黄原胶含量分别为0%,0.5%,1.5%的试样,抗压强度分别损失了42.75%,17.2%,14.04%。(2)加固土的抗压强度与干湿循环次数之间保持指数下降的关系,当循环次数达到4次后,随着循环次数的进一步增加,抗压强度和弹性模量均在较小的变化范围内波动。(3)随着干湿循环次数的增加,黄原胶加固土的孔隙率表现出先增加后减小的趋势,连通孔隙不断扩展,而孤立孔隙表现出先增加后减小的趋势。(4)随着试样的干燥,黄原胶在土颗粒间形成网状基质,提高土体的强度和耐干湿循环能力。The wetting-drying cycle has an important effect on the engineering properties of rock and soil.The CT scanning technology and testing methods for mechanical properties are used to study the deterioration mechanism of clay reinforced with xanthan gum with different contents(0%,0.5%,and 1.5%)under different times of wetting-drying cycles(0,1,4,8,12).The main conclusions are as follows:(1)The xanthan gum can effectively improve the compressive strength and wetting-drying resistance of the soil.With the increase of the xanthan gum content,the strength loss after wetting-drying cycles decreases gradually.When the times of cycles increase from 0 to 4,the compressive strength of the soil with the xanthan gum contents of 0%,0.5%and 1.5%decreases by 42.75%,17.2%and 14.04%,respectively.(2)There is an exponentially decreasing relationship between the compressive strength of the reinforced soil and the times of wetting-drying cycles.When the times of cycles reach 4,the change values of the compressive strength and the elastic modulus of the samples all fluctuate in a small range with the further increase of the times of cycles.(3)With the increase of the times of wetting-drying cycles,the porosity of the xanthan gum-reinforced soil shows a trend of increasing first and then decreasing.With the increase of the times of the wetting-drying cycles,the connected pores continue to expand,while the isolated pores show a trend of increasing first and then decreasing.(4)With the drying of the sample,the xanthan gum forms a network matrix among the soil particles,which improves the strength of the soil and the capability of resistance to wetting-drying cycles.

关 键 词：生物聚合物 黄原胶 抗压强度 CT扫描 微观结构 劣化机制 

分 类 号：TU43[建筑科学—岩土工程]