单轴冲击及一维动静组合加载下红砂岩力学特性研究

发布时间：2018-04-23 04:27

本文选题：动力学特性 + 红砂岩　；参考：《昆明理工大学》2015年硕士论文

【摘要】：为了研究岩石的动力学特性,选用红砂岩作为研究对象,利用改进的SHPB试验装置进行室内动力学试验-单轴冲击及一维动静组合试验,从获取的应力应变曲线,割线模量、动态抗压强度、动态增长因子、能量传递规律、破坏模式,分形特征等方面对红砂岩的动力学特性进行分析,得到以下结论：(1)单轴冲击及一维动静组合试验应力应变曲线整体可以划分为三个阶段：弹性阶段,屈服阶段及塑性阶段,随着应变率的变化,三个阶段有各自的特点。本文单轴冲击试验中,红砂岩的割线模量随着应变率的变化总体呈增大趋势,而一维动静组合试验中,随着应变率的变化,不同轴压下红砂岩的割线模量并没有表现出一定的规律,但应变率一定时,随着轴压的增加,割线模量呈现出先增大后减小的趋势；(2)单轴冲击及一维动静组合试验中,红砂岩的动态抗压强度均表现出明显的应变率效应,即都随着应变率的增大而增大,但在一维动静组合试验中,应变率一定时,随着轴压的增大,动态抗压强度会呈现先增大后减小的趋势；(3)单轴冲击及一维动静组合试验下,随着应变率的提高,红砂岩的单位体积吸收能增大,随着入射能的增加,红砂岩的单位体积吸收能也增大,但在一维动静组合试验下,应变率一定时,随着轴压的增大,红砂岩的单位体积吸收能呈现出先增大后减小的趋势；(4)单轴冲击荷载作用下红砂岩的破坏模式表现为拉伸破坏,一维动静组合加载试验下,岩样的破坏模式表现为剪切破坏,只是会因为应变率的变化,有一定的不同,应变率越大,岩样破碎程度越高；(5)单轴冲击及一维动静组合加载试验下,红砂岩的破碎块度均表现出很好的分维特性,随着入射能的增大,红砂岩的分形维数D值增大,也就是说入射能越大,岩样破碎程度越高。
[Abstract]:In order to study the dynamic characteristics of rock, red sandstone was selected as the object of study. The laboratory dynamic test, uniaxial impact test and one-dimensional dynamic and dynamic combination test were carried out by using the improved SHPB test device. The obtained stress-strain curve and Secant modulus were obtained. Dynamic compressive strength, dynamic growth factor, energy transfer law, failure mode, fractal characteristics and other aspects of the dynamic characteristics of red sandstone are analyzed. The following conclusions are obtained: (1) the stress-strain curves of uniaxial impact and one-dimensional static and dynamic combination tests can be divided into three stages: elastic stage, yield stage and plastic stage. With the change of strain rate, the three stages have their own characteristics. In uniaxial impact test, the Secant modulus of red sandstone increases with strain rate, while in one dimensional dynamic and static combination test, it increases with strain rate. The Secant modulus of red sandstone under different axial compression does not show a certain rule, but when the strain rate is constant, with the increase of axial compression, the Secant modulus shows a tendency of increasing first and then decreasing.) in uniaxial impact and one-dimensional dynamic and dynamic combination tests, the Secant modulus of red sandstone shows a tendency of first increasing and then decreasing. The dynamic compressive strength of red sandstone shows obvious strain rate effect, that is, the strain rate increases with the increase of strain rate, but in one dimensional dynamic and static combination test, the strain rate increases with the increase of axial compression. Dynamic compressive strength increases first and then decreases. Under uniaxial impact and one-dimensional dynamic and dynamic combination tests, with the increase of strain rate, the unit volume absorption energy of red sandstone increases and the incident energy increases. The absorption energy per unit volume of red sandstone also increases, but when the strain rate is constant, with the increase of axial compression, The absorption energy per unit volume of red sandstone increases first and then decreases. (4) the failure mode of red sandstone under uniaxial impact load is tensile failure, and the failure mode of rock sample is shear failure under one-dimensional dynamic and static combined loading test. However, due to the variation of strain rate, there is a certain difference. The greater the strain rate, the higher the degree of fragmentation of rock samples.) under uniaxial impact and one-dimensional dynamic and static combined loading tests, the fragmentation of red sandstone shows good fractal characteristics. With the increase of incident energy, the fractal dimension D of red sandstone increases, that is to say, the higher the incident energy, the higher the fracture degree of rock samples.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD313

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