干湿循环下不同初始干密度泥岩强度劣化研究  

Strength Deterioration of Mudstone with Different Initial Dry Densities under Dry-wet Cycles

作　　者：朱江鸿 余荣光 韩淑娴 童艳梅 张虎元[1,2] 甄作林 ZHU Jianghong;YU Rongguang;HAN Shuxian;TONG Yanmei;ZHANG Huyuan;ZHEN Zuolin(School of Civil Engineering and Mechanics,Lanzhou University,Lanzhou 730000,China;Key Laboratory of Mechanics on Disaster and Environment in Western China,Ministry of Education,Lanzhou University,Lanzhou 730000,China;Northwest Research Institute Co.,Ltd.of C.R.E.C,Lanzhou 730000,China)

机构地区：[1]兰州大学土木工程与力学学院,甘肃兰州730000 [2]兰州大学西部灾害与环境力学教育部重点实验室,甘肃兰州730000 [3]中铁西北科学研究院有限公司,甘肃兰州730000

出　　处：《铁道学报》2021年第10期109-117,共9页Journal of the China Railway Society

基　　金：中国铁路总公司科技研究开发计划(2017G007-G-1-2);中央高校基本科研业务费(lzujbky-2017-ct02)。

摘　　要：由于季节性降雨和地下水位升降,岩质边坡中泥岩在干湿循环中强度发生劣化,对岩质边坡的稳定性具有不良影响。以兰新高铁岩质边坡的泥岩为研究对象,对不同初始干密度泥岩在干湿循环中进行单轴抗压、抗拉和SEM试验。研究发现,初始干密度相同时,随干湿循环次数的增大,泥岩的单轴抗压强度、弹性模量、抗拉强度、黏聚力逐渐减小,其劣化速率呈减小趋势,干湿循环对其劣化程度呈增大趋势,摩擦角下降幅度较小。干湿循环次数相同时,随初始干密度的增大,泥岩单轴抗压强度、弹性模量、抗拉强度和黏聚力逐渐增大,干湿循环对其劣化程度都呈增大趋势。比较同一强度参数(单轴抗压强度、弹性模量、抗拉强度或黏聚力),随干湿循环次数的增大,三种初始干密度泥岩之间差值呈减小的趋势。在干湿循环递进过程中,泥岩颗粒间联结能力逐渐减弱,孔隙表面复杂程度逐渐增大,不同初始干密度泥岩的颗粒间联结能力差别呈减小趋势,与宏观方面的规律相对应。干湿循环对泥岩强度的劣化与循环次数和初始干密度密切相关。Due to seasonal rainfall and groundwater level fluctuation,the strength of mudstone in the rock slope is deteriorated under dry-wet cycles,which has an adverse effect on the stability of the rock slope.In the case of the mudstone in the rock slope of Lanzhou-Urumqi high-speed railway,the uniaxial compressive test,tensile test and SEM test of the mudstone with different initial dry densities in the dry-wet cycle were carried out.It is found that under the same initial dry density,with the increase in the number of dry and wet cycles,the mechanical parameters(uniaxial compressive strength,elastic modulus,tensile strength,cohesive force)of the mudstone decrease and the degradation rates of the mechanical parameters decrease.The dry wet cycle increases the degree of deterioration and the friction angle decreases slightly.Under the same number of dry wet cycles,with the increase of initial dry density,the mechanical parameters of the mudstone gradually increase,and the deterioration degrees of the mechanical parameters under dry-wet cycles increase.Compared with the same mechanical parameter,the difference between the mudstone with three initial dry densities gradually decreases with the increase of dry-wet cycle number.In terms of microstructure,in the progress of the dry-wet cycle,the binding ability of mudstone particles gradually weakens,and the complexity of the pore surface gradually increases.The difference in the binding ability for mudstone with three initial dry densities decreases,which corresponds to macroscopic laws.Therefore,the effects of dry-wet cycles on the mudstone strength are closely related to number of cycles and initial dry density.

关 键 词：泥岩 干湿循环 初始干密度 强度 劣化 

分 类 号：TU411[建筑科学—岩土工程]