不同化学腐蚀下砂岩冻融力学特性劣化的试验研究  

Laboratory Investigation on the Mechanical Properties of Sandstone Immersed in Different Chemical Corrosion under Freeze-thaw Cycles

作　　者：韩铁林[1,2,3] 师俊平 陈蕴生[1,2] 李智慧[2] 李春磊 Tielin Han;Junping Shi;Yunsheng Chen;Zhihui Li;Cunlei Li(Institute of Geotechnical Engineering, Xi ＇an University of Technology, Xi＇ an, 710048;School of Civil Engineering and Architecture, X i ~ an University of Technology, Xi＇an , 710048;Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, Shenzhen University, Shenzhen, 518060)

机构地区：[1]西安理工大学土木建筑工程学院岩土工程研究所,西安710048 [2]西安理工大学土木建筑工程学院工程力学系,西安710048 [3]深圳大学,广东省滨海耐久性重点实验室,深圳518060

出　　处：《固体力学学报》2017年第6期503-520,共18页Chinese Journal of Solid Mechanics

基　　金：国家自然科学基金项目(51269024,11302167和51769026);陕西省教育厅重点实验室科研计划项目(16JS074);宁夏自然科学基金(重点项目)(NZ17002)资助

摘　　要：通过研究砂岩试样在酸性Na_2SO_4溶液、中性Na_2SO_4溶液和碱性NaOH溶液中浸泡并经历冻融作用后的物理力学特征,分析了砂岩在不同化学溶液中腐蚀30d后及再经历不同冻融循环次数作用后其物理力学特征的变化规律,同时,借助于体视显微镜和SEM扫描电镜对试样微细观结构的损伤劣化进行了观察,并基于孔隙率的变化建立损伤变量来定量的描述试样的损伤劣化程度.试验结果表明:随着冻融循环次数的增加,浸泡在不同化学溶液中砂岩试样的峰值强度及其弹性模量均呈现出指数函数的劣化趋势,而其峰值应变却按指数函数的趋势增加.不同化学溶液下砂岩试样的损伤程度随着冻融循环次数的增加而逐渐加剧,酸性溶液下试样的损伤程度大于中性溶液和碱性溶液下的损伤程度,碱性化学溶液下试样的冻融损伤程度最小.酸性溶液加剧了冻融作用下砂岩试样的损伤劣化程度,而中性至碱性溶液下其冻融损伤程度却得到一定的缓解.化学腐蚀作用与冻融循环作用相互促进、共同影响着砂岩试样的损伤劣化程度.The physical and mechanical characteristics of sandstone specimens eroded in different chemical solutions（the acidic Na2SO4 solution,neutral Na2SO4 solution and alkaline NaOH solution）and subjected to different freeze-thaw cycles are experimentally studied.The variation of physical and mechanical characteristics of sandstone specimens immersed in different chemical solutions for 30 days and then exposed to different freeze-thaw cycles is analyzed.Meanwhile damage in the microstructure of sandstone specimens is observed by means of stereo microscope and scanning electron microscope（SEM）.The damage variable is defined based on the change of porosity to quantitatively analyze the degree of damage of sandstone specimens.The test results show that,for different chemical solutions,the peak strength and elastic modulus of sandstone specimens decrease exponentially with the increase of freeze-thaw cycles,but the peak axial strain increases exponentially with the increase of freeze-thaw cycles.With the increase of freeze-thaw cycles,the damage of sandstone specimens gradually increases when soaked in different chemical solutions.The degree of damage of sandstone specimens soaked in acidic chemical solution is higher than that in neutral chemical solution and alkaline chemical solution,which is the lowest in the alkaline NaOH solution.The degree of damage and degradation of sandstone specimens exposed to freeze-thawing cycles is intensified by the acidic chemical solution,which however,is mitigated as the sandstone specimens are soaked in neutral solution or alkaline solution.Chemical corrosion together with freeze-thaw cycles can give mutual promotion and have mutual influence on the degradation and damage of sandstone specimens.

关 键 词：岩石力学 砂岩 化学腐蚀 冻融循环 微细观结构 力学特性 损伤变量 

分 类 号：TU45[建筑科学—岩土工程]