贺兰口岩画载体岩石表层风化壳损伤特征与机制研究  

STUDY ON THE DAMAGE CHARACTERISTICS AND MECHANISM OF HELAN PASS PETROGLYPH CARRIER ROCK SURFACE WEATHERING CRUST

作　　者：崔凯[1,2] 杨辉 吴国鹏[1] 林浩 陈一凡 李星月 CUI Kai;YANG Hui;WU Guopeng;LIN Hao;CHEN Yifan;LI Xingyue(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Mechanics on Disaster and Environment in Western China(Lanzhou University),Ministry of Education,Lanzhou 730000,China;Yinchuan Helan Mountain Petroglyph Management Office,Yinchuan 750000,China)

机构地区：[1]兰州理工大学教育部土木工程防灾减灾工程中心,兰州730050 [2]兰州大学西部灾害与环境力学教育部重点实验室,兰州730000 [3]银川市贺兰山岩画管理处,银川750000

出　　处：《工程地质学报》2024年第6期1935-1950,共16页Journal of Engineering Geology

基　　金：国家自然科学基金项目(资助号:42107206);中国博士后科学基金项目(资助号:20023MD734145);甘肃省自然基金项目(资助号:22JR5RA292)。

摘　　要：刻痕变浅、开裂、剥落与溶蚀等与岩石表层风化壳的损伤破坏行为直接相关的病害高度发育是贺兰口岩画破坏的重要原因。通过对岩画载体岩石表层风化壳分别在不同溶液浸泡条件下、不同次数的干湿与冻融循环实验来系统探索其在冻融、干湿和化学溶蚀不同耦合作用下的损伤特征,而后通过与其母岩在相同劣化条件下损伤变量、XRD与SEM分析结果的对比来揭示其与母岩的差异性损伤机理。研究表明:岩石表层风化壳试样的质量、表面硬度、抗折强度、应力-应变特征总体呈现随循环次数的增加而逐渐差异性衰减的规律,且变化速率呈现3个阶段,具有45次和90次两个明显的拐点。对比分析损伤变量得到表层风化壳在损伤过程中较母岩存在损伤拐点滞后和损伤速率较快的差异性,损伤机理的本质区别在于较大的孔隙率和单一由斜长石的水解、化学溶蚀以及盐结晶和溶解3种作用差异性组合而造成岩石内部线性孔隙、孔洞数量和连接快速增长,这种差异为岩画的刻痕变浅、开裂、剥落与溶蚀等病害的高度发育提供了佐证。The scotch shallowing,cracking,exfoliation,solution and other diseases directly related to the damage of rock surface weathering are highly developed,which are the important reasons for the damage of Helan Pass petroglyph.In this study,those samples immersed in different solutions,and systematically explored the damage characteristics of metamorphic sandstone surface crust under different coupling effects of freezing-thawing,drying-wetting and chemical dissolution.Then,the study reveals differential damage mechanism between rock surface weathering crust and original rock by comparing the damage variables,XRD and SEM analysis results under the same deterioration condition as the original rock.The results show that the mass,surface hardness,flexural strength and stress-strain characteristics of the samples generally show a law of gradual differential attenuation with the increase of the number of cycles,and the change rate presents three stages,with two obvious inflection points of 45 times and 90 times.By comparing the damage variables of rock surface weathering crust and original rock,it is found that the damage inflection point of rock surface weathering crust lags behind and the damage rate is faster than that of original rock,the essential difference of the damage mechanism between the rock surface weathering crust and the original rock is that the porosity of the rock surface weathering crust is larger than that of the original rock and the differential combination of hydroxylation,chemical dissolution of single plagioclase and salt crystallization and dissolution,that results in a rapid increase in the number and connections of linear pores and pores in the rocks,this difference provides evidence for the high development of petroglyph's diseases such as scotch shallowing,cracking,exfoliation and solution.

关 键 词：贺兰口岩画 表层风化壳 抗折强度 损伤特征 机理对比 

分 类 号：TU458[建筑科学—岩土工程]