柴油污染膨胀土热脱附后无荷载膨胀率的变化  

The change of unloaded expansion rate of diesel-contaminated expansive soil after thermal desorption

作　　者：杜静[1] 淳野杨 周东[2,3] 刘宗辉 戴书剑[4] DU Jing;CHUN Ye-yang;ZHOU Dong;LIU Zong-hui;DAI Shu-jian(Guangxi Transport Vocational and Technical College,Nanning 530023,China;School of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Engineering Safety of Guangxi,Nanning 530004,China;Guangxi Bossco Environmental Protection Technology Co.,Ltd.,Nanning 530007,China)

机构地区：[1]广西交通职业技术学院,广西南宁530023 [2]广西大学土木建筑工程学院,广西南宁530004 [3]广西防灾减灾重点实验室,广西南宁530004 [4]广西博世科环保科技股份有限公司,广西南宁530007

出　　处：《广西大学学报（自然科学版）》2021年第6期1442-1451,共10页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(51378132,42067045);广西高校中青年教师科研基础能力提升项目(2021KY1133);广西交通职业技术学院自然科学研究项目(JZY2019KAZ05)。

摘　　要：为了得到热脱附后柴油污染膨胀土的膨胀特性,以南宁膨胀土为背景土,制备不同掺量的柴油溶度污染土;并在模拟热脱附环境中进行实验室土壤修复,得到修复后的柴油污染膨胀土,最后进行无荷载膨胀率测试。同时利用XRD分析、压汞测试和气相色谱测试进行机理分析。试验结果表明:柴油掺量一定时,加热温度越高,无荷载膨胀率越低;加热温度一定时,柴油掺量越大,无荷载膨胀率越小。机理分析结果显示:柴油的掺入对黏土矿物基本没有影响;加热温度和柴油掺量的增加可增大柴油污染膨胀土孔隙率和孔隙平均直径,虽然加快了水分浸入,增强黏土水化作用,但是增大的膨胀空间,削弱了膨胀潜势,最终导致无荷载膨胀率降低。同时,残余“碳”存在,可减缓或者阻隔水与黏土矿物表面的水化作用,导致无荷载膨胀率降低。To obtain the swelling characteristics of diesel oil contaminated expansive soil after thermal desorption,the diesel oil solubility contaminated soil with different content was prepared with Nanning expansive soil as the background soil;The laboratory soil remediation was carried out in the simulated thermal desorption environment to obtain the repaired diesel contaminated expansive soil.Finally,the no-load expansion rate was tested.At the same time,the mechanism was analyzed by XRD analysis,mercury injection test and gas chromatography.The test results show that the higher the heating temperature is,the lower the no-load expansion rate is when the content of diesel is certain;When the heating temperature is constant,the greater the diesel content,the smaller the no-loaded expansion rate.The results of mechanism analysis show that the addition of diesel has no effect on clay minerals;The increase of heating temperature and diesel content can increase the porosity and average pore diameter of diesel contaminated expansive soil.Although it accelerates the water immersion and enhances the hydration of clay,the increased expansion space weakens the expansion potential,and finally leads to the reduction of the no-loaded expansion rate.At the same time,the existence of residual“carbon”can slow down or block the hydration between water and clay mineral surface,resulting in the reduction of the no-loaded expansion rate.

关 键 词：热脱附 无荷载膨胀率 黏土矿物 孔隙率 碳 

分 类 号：TU411[建筑科学—岩土工程]