基于核磁共振试验的粉砂岩干湿循环损伤演化研究  

Dry-wet cyclic damage evolution of siltstone based on nuclear magnetic resonance test

作　　者：李文良 张铁 李佳林 罗刚 周建伟 LI Wenliang;ZHANG Tie;LI Jialin;LUO Gang;ZHOU Jianwei(Sichuan Communication Surveying&Design Institute Co.,Ltd.,Chengdu 610017,China;Sichuan Central Facilities Construction Co.,Ltd.,Mianyang 621011,China;School of Earth Science and Environmental Engineering,Southwest Jiaotong University,Chengdu 610036,China;Sichuan Tibet Railway Co.,Ltd.,Chengdu 610094,China)

机构地区：[1]四川省交通勘察设计研究院有限公司,四川成都610017 [2]四川中部设施建设有限公司,四川绵阳621011 [3]西南交通大学地球科学与环境工程学院,四川成都610036 [4]川藏铁路有限公司,四川成都610094

出　　处：《水运工程》2023年第3期24-30,49,共8页Port & Waterway Engineering

基　　金：国家重点基础研究发展计划(973计划)项目(2017YFD0800501)。

摘　　要：受降雨入渗和地下径流影响,内陆港口岩石地基经历着干湿循环作用,地基承载能力随时间推移而逐渐衰减。以粉砂岩为研究对象,开展5种干湿循环条件下的核磁共振和单轴压缩试验。基于几何损伤和能量损伤,结合岩石孔隙体积及弹性模量变化规律,建立两种损伤演化方程,分析粉砂岩干湿循环损伤演化机制。结果表明:粉砂岩T_(2)谱图表现出3个峰,分别对应微小、小尺寸和大尺寸孔隙,粉砂岩的结构孔隙以微小、小尺寸孔隙为主;随着干湿循环作用的加强,T_(2)谱峰总面积、孔隙度均表现出幂函数递增规律,岩石孔隙数量逐渐递增;干湿循环促进峰值强度和弹性模量的衰减,当循环次数达到16次时,衰减幅度逐渐平缓。Under the influences of rainfall infiltration and underground runoff,the rock foundation of inland port undergoes the dry-wet cycle,and the bearing capacity of the foundation gradually decreases with time.Taking siltstone as the research object,we carry out nuclear magnetic resonance(NMR)and uniaxial compression tests under five dry-wet cycle conditions.Based on the geometric damage and energy damage,we build two damage evolution equations combining with the change law of rock pore volume and elastic modulus,and analyze the dry-wet cycle damage evolution mechanism of siltstone.The results show that the T_(2)spectrum of siltstone shows three peaks,corresponding to smaller,small and large pores respectively,and the structural pores of siltstone are smaller and small pores.With the strengthening of dry-wet cycle,the total area of T_(2)spectrum peak and porosity show a power function increasing law,and the number of rock pores increases gradually.The dry-wet cycle promotes the attenuation of the peak strength and elastic modulus.When the number of cycles reaches 16,the attenuation amplitude gradually flattens.

关 键 词：港口地基工程 核磁共振 干湿循环 孔隙分布 T_(2)谱 损伤演化 

分 类 号：U655[交通运输工程—港口、海岸及近海工程]