两种水环境下干湿循环作用对贺兰山砂岩抗拉强度的劣化研究  

The degradation of tensile strength of Helan mountain sandstone by dry-wet cycle in two water environments

作　　者：杨有贞 樊怡[1] 马文国 强文华 金梦华[1] 郭家 何贤元 YANG Youzhen;FAN Yi;MA Wenguo;QIANG Wenhua;JIN Menghua;GUO Jia;HE Xianyuan(Institute of Physics and Electrical Engineering,Ningxia University,Yinchuan Ningxia 750021;Institute of Solid Mechanics,Yinchuan Ningxia University,Yinchuan Ningxia 750021)

机构地区：[1]宁夏大学物理与电子电气工程学院,宁夏银川750021 [2]宁夏大学固体力学研究所,宁夏银川750021

出　　处：《宁夏师范学院学报》2019年第1期63-70,共8页Journal of Ningxia Normal University

基　　金：国家自然科学基金(11662015;51468053;51768059);宁夏重点研发项目(2016KJHM35);宁夏高校科学研究项目(NGY2016060)

摘　　要：选取贺兰山岩画区砂岩为研究对象,首先,采用显微镜正交偏光对岩矿进行了分析,鉴定结果为钙质胶结不等粒长石砂状砂岩.其次,分别在pH=2. 0和pH=7. 0溶液中,进行浸泡-烘干处理模拟0次、5次、10次、20次、40次、60次干湿循环过程,每组3个岩样,将其在岩石试验机上分组进行劈裂试验.最后,分析试验循环次数对强度的影响,给出砂岩破坏形式,模拟干湿循环次数与单轴抗压强度之间的拟合关系,得到抗拉强度损伤率.研究结果表明:干湿循环对砂岩的损伤是渐进发生,因为水解反应,岩石抗拉强度损伤率随循环次数的增加而增加,且前期的影响最大,砂岩在酸性环境干湿循环后力学性质的劣化程度强于中性环境.The sandstone in the rock painting area of Helan Mountain was selected as the research object.Firstly,the rock ores were analyzed by microscope orthogonal polarization,which were identified as calcareous cement unequal feldspar sandstone.Then,The dry-wet cycles were simulated with 0,5,10,20,40 and 60 times of 3 rock samples in each group in the pH=2.0 and pH=7.0 solutions,respectively.And the split tests were used.,The effect of test cycle times on strength was analyzed,and the failure mode of sandstone was given.The fitting relationship between the number of dry-wet cycles and the uniaxial compressive strength was simulated,and the tensile strength loss rate was gotten.The results show that the damage of sandstone by dry-wet cycle is gradual.Because of the hydrolysis reaction,the damage rate increases with the increasing of the number of cycles,and the influence of earlier stage dry-wet cycle is the greatest.Moreover,the deterioration of mechanical properties of sandstone in acid environment is stronger than that in neutral environment after dry-wet cycling.

关 键 词：干湿循环 抗拉强度 劣化 

分 类 号：TU443[建筑科学—岩土工程]