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工程科学与技术:2022,54(6):194-203
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初始损伤–载荷–冻融作用下红砂岩的孔隙结构及力学特性
(1.郑州大学 黄河实验室 水利科学与工程学院,河南 郑州 450001;2.深圳大学 深地科学与绿色能源研究院 土木与交通工程学院,广东 深圳 518060;3.中铁工程设计咨询集团有限公司 郑州设计院,河南 郑州 450000;4.合肥工业大学 土木与水利工程学院,安徽 合肥 230009)
Pore Structure and Mechanical Properties of Red Sandstone Under the Action of Initial Damage–Load–Freeze-thaw
(1.Yellow River Lab., College of Water Conservancy Eng., Zhengzhou Univ., Zhengzhou 450001, China;2.Inst. of Deep Earth Sciences and Green Energy, College of Civil and Transportation Eng., Shenzhen Univ., Shenzhen 518060, China;3.Zhengzhou Design Inst., Railway Eng. Consulting Group Co. Ltd., Zhengzhou 450000, China;4.College of Civil Eng., Hefei Univ. of Technol., Hefei 230009, China)
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投稿时间:2021-04-29    修订日期:2021-08-07
中文摘要: 中国西部寒区岩体内普遍存在裂隙等初始损伤,而载荷和冻融作用会极大地削弱裂隙岩体的强度,进而引发工程灾害。为了准确评估载荷和冻融对寒区不同损伤岩体孔隙结构及力学性质的影响,采用核磁共振技术依次测试红砂岩在初始损伤、循环载荷、冻融循环3个阶段后的孔隙度、T2谱分布等微观孔隙参数;随后,对损伤后试样进行声发射监测下单轴加载测试。结果表明:载荷或冻融作用对不同初始损伤红砂岩孔隙结构和力学性质有相似的影响规律。具体来说,随着力学循环加载,红砂岩的孔隙度增大,以原有孔隙扩展为主;随着冻融循环作用,红砂岩的孔隙度继续增大,以新增小孔隙和原有孔隙扩展为主。载荷、冻融都将导致试样强度、弹性模量的损伤,单一冻融作用下,红砂岩试样强度损伤为5%~10%;但在载荷、冻融先后作用下,试样强度损伤达到20%~30%。不同裂隙损伤的红砂岩初始强度越小,其遭受载荷和冻融作用后相对初始强度的损伤越大。另外,遭受载荷和冻融损伤试样的孔隙度增幅与其强度降幅呈正相关。上述研究成果可为中国寒区工程的稳定性设计和安全施工提供依据。
Abstract:In the cold regions of western China, initial damages, such as fissures, are ubiquitous in the rock mass, while the combined effects of load and freeze-thaw will greatly weaken the strength of rock mass and cause engineering disasters. To quantify and evaluate the influences of cyclic load and freeze-thaw cycles on the pore parameters and mechanical properties of different damaged rock masses in cold regions, nuclear magnetic resonance technology was used to test the microscopic pore parameters (such as the porosity and T2 spectrum distribution) of red sandstone at the initial damage stage, cyclic load stage and freeze-thaw cycle stage. Subsequently, the damaged samples were subjected to uniaxial loading with acoustic emission monitoring. The test results show that the pore structure and mechanical properties of red sandstones with different initial damage demonstrate consistent behaviors under the sequential action of cyclic load and freeze-thaw cycles. The porosity increases for the samples subjected to cyclic mechanical loading, due to the expansion of original pores. The porosity continues to increase for red sandstone subjected to freeze-thaw cycles, resulting from the newly generated small pores and expansion of original pores. In general, both cyclic load and freeze-thaw cycles can deteriorate the strength and elastic modulus of the samples. The strength reduction of the red sandstone was 5%~10% when subjected to freeze-thaw cycles, and was 20%~30%, under the combined load and freeze-thaw cycles. The lower the initial strength of red sandstone with different fracture damage, the greater the damage of the sample relative to the initial strength after being subjected to load and freeze-thaw. The sandstone samples were found to experience greater damage with the lower initial strength when subjected to load and freeze-thaw. In addition, the porosity increment of the samples subjected to the combined load and freeze-thaw cycles is found positively correlated with the decrease in the sample strength. The above research results can provide an important basis to achieve stable design and safe construction of engineering in cold regions of China.
文章编号:202100380     中图分类号:TU452    文献标志码:
基金项目:国家自然科学基金项目(42077249);国家青年自然科学基金项目(51804203);中国博士后科学基金项目(2020M682882;2020TQ0203);广东省基础与应用基础研究基金项目(2020A1515110468;2020A1515111193)
作者简介:第一作者:王飞(1988-),男,博士.研究方向:岩石力学.E-mail:wangfei0826@163.com
引用文本:
王飞,高明忠,邱冠豪,汪亦显,周昌台,王之禾.初始损伤–载荷–冻融作用下红砂岩的孔隙结构及力学特性[J].工程科学与技术,2022,54(6):194-203.
WANG Fei,GAO Mingzhong,QIU Guanhao,WANG Yixian,ZHOU Changtai,WANG Zhihe.Pore Structure and Mechanical Properties of Red Sandstone Under the Action of Initial Damage–Load–Freeze-thaw[J].Advanced Engineering Sciences,2022,54(6):194-203.