岩石疲劳变形特性与疲劳门值计算方法研究  

Research on Rock Fatigue Deformation Characteristics and Calculation Method of Fatigue Threshold Value

作　　者：曾立兵 ZENG Libing(China Railway 19^(th)Bureau Group Co.Ltd.,Beijing 100176,China)

机构地区：[1]中铁十九局集团有限公司,北京100176

出　　处：《铁道建筑技术》2021年第8期6-9,23,共5页Railway Construction Technology

基　　金：中铁十九局集团有限公司科研计划项目(19-06A)。

摘　　要：利用MTS landmark动态电液伺服测试系统进行石灰岩单轴循环荷载作用下疲劳试验,研究其变形及疲劳破坏特性。试验数据分析结果表明:当上限应力大于疲劳门槛值时,石灰岩疲劳破坏轴向不可逆变形表现出与其他岩石类似的力学特性。石灰岩疲劳破坏轴向不可逆变形表现为初始变形→等速稳定变形→加速变形;且呈现疏→密→疏的发展规律,表现为非稳定疲劳特性。上限应力小于疲劳门槛值,岩石变形发展状态趋于稳定,表现出稳定疲劳特性。本文提出疲劳门槛值理论计算方法,通过该方法计算得出的疲劳门槛值与试验确定的门槛值较为接近。研究结果有助于从不同角度进一步研究岩石的动态疲劳特性,以丰富岩石疲劳研究方法和手段。The fatigue test of limestone under uniaxial cyclic load is performed with MTS landmark dynamic electrohydraulic servo test system to study its deformation and fatigue failure characteristics. The experimental data analysis shows that when the maximum stress is greater than the fatigue threshold value,limestone fatigue damage axial irreversible deformation shows similar mechanical properties to other rocks. It is characterized by initial deformation→constant velocity stable deformation→accelerated deformation;and it presents the development law from sparse to dense to sparse,showing the unstable fatigue characteristics. When the maximum stress is less than the fatigue threshold value,the deformation shows a stable development state,reflecting the stable fatigue characteristics. The theoretical calculation method of fatigue threshold value is put forward,and the calculated fatigue threshold value is in good agreement with the threshold value determined by experiment. The research results are helpful to further study the dynamic fatigue characteristics of rocks from different angles,and enrich the research methods and means of rock fatigue.

关 键 词：石灰岩 轴向不可逆变形 疲劳损伤 疲劳门槛值 试验 计算方法 

分 类 号：TU45[建筑科学—岩土工程]