复杂应力条件下红砂岩屈服前力学性能的研究  

Mechanical Properties of Red Sandstone Before Yielding Under Complex Stress Conditions

作　　者：赵厚发 宁麟 邓小江 ZHAO Houfa;NING Lin;Deng Xiaojiang(College of Civil Engineering,Guizhou University,Guiyang 550025)

机构地区：[1]贵州大学土木工程学院,贵阳550025

出　　处：《土工基础》2023年第3期477-483,共7页Soil Engineering and Foundation

摘　　要：为研究连续复杂应力循环加卸载作用下岩石能量特征,开展红砂岩小幅值等幅循环+变幅值(与正弦波相似)轴向循环加卸载试验,探究了岩石试样在循环加卸载作用下屈服前的能量变化规律,同时探究了利用小幅值循环加卸载的能量来表征试样所处的应变阶段。试验结果表明:①在加卸载试验过程中外部输入的能量主要转化为弹性能储存,部分能量被消耗,即损耗能;②输入能、弹性能、损耗能占比变化与试样所处的应变阶段一致,可通过能量的变化来定量表征试样在持续荷载作用下的变形特征及阶段;③等幅循环阶段的能量随着应力的增大而逐渐减小,可通过在小幅度循环加卸载作用下的能量变化来间接评估试件损伤及所处的变形阶段;④各循环阶段峰值应力处的耗能比变化在45MPa阶段是一个拐点,同时,能量的变化也存在一定的“记忆性”。To study the energy characteristics of intact rock samples under cyclic loading and unloading conditions and continuous complex stress conditions,the axial cyclic loading and unloading tests on the red sandstone with small values of constant amplitude cycle+amplitude variation(similar to sine wave)was performed to explore the energy variation rule of intact rock samples before yielding under the cyclic loading and unloading.At the same time,the strain stage of the sample was characterized by the energy of cyclic loading and unloading with small value.The test results show that:(1)During the loading and unloading tests,the external input energy is mainly converted into elastic energy storage,and some energy is consumed,that is,the dissipated energy.(2)The change of the proportion of input energy,elastic energy and loss energy is consistent with the strain stage of the sample,and the deformation characteristics and stage of the sample under sustained load can be quantitatively characterized by the change of energy.(3)The energy in the constant amplitude cyclic stage decreases gradually with the increase of stress,and the damage and deformation stage of the specimen can be indirectly assessed by the energy change under the cyclic loading and unloading with a small amplitude.(4)The change of energy consumption ratio at peak stress in each cycle stage is an inflection point at 45MPa stage,and the change of energy also has a certain“memory”.

关 键 词：复杂应力 能量特征 弹性能 损耗能 耗能比 

分 类 号：TU457[建筑科学—岩土工程]