三维静应力下红砂岩冲击力学特性试验研究

发布时间：2018-02-27 04:10

本文关键词： 岩石力学霍普金森压杆三维动静组合加载岩爆破坏模式　出处：《昆明理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：为研究岩石的动力学特性和岩爆发生的动力学机理,以红砂岩为研究对象,利用改进的霍普金森压杆试验装置,对红砂岩进行预加载三维高静应力又受冲击荷载试验,分析红砂岩的变形特性、强度特性、能量耗散规律以及破坏模式等动力学特性。同时基于三维动静组合加载下红砂岩的动力学特性,简要分析了岩爆发生的动力学机理。研究结果表明:1、红砂岩在单轴压缩条件下应力-应变曲线分为四个阶段,分别为压密阶段、弹性阶段、破坏发展阶段、破坏后阶段。在单轴压缩条件下破坏模式有三种类型,分别为拉伸破坏、单斜面剪切破坏、X状共轭斜面剪切破坏。2、红砂岩在三维动静组合加载下的应力-应变曲线相比单轴压缩仅有三个阶段,分别为弹性阶段、破坏发展阶段、破坏后阶段,而无压密阶段。红砂岩的应力-应变曲线在不同应变率下表现出应变回弹、应力跌落及峰后塑性三种类型。在三维动静组合加载下,当轴压一定时,割线模量随围压的增大而增大;当围压一定时,割线模量随轴压的增大呈现先增大后降低的趋势。在三维动静组合加载下,当轴压一定时,平均应变率随围压的增大而减小;当围压一定时,随轴压的增大先减小后增大。3、红砂岩在三维动静组合加载下,当轴压一定时,红砂岩的动态抗压强度随围压的增大而增大;当围压一定时,红砂岩的动态抗压强度随轴压的增大呈先增大后降低的趋势。在三维动静组合加载下,红砂岩的动态抗压强度随应变率的增大而增大,表现出很好的应变率相关性。在三维动静组合加载下,红砂岩动态抗压强度增长因子与应变率的1/3呈线性递增关系,并有良好的线性相关拟合性。4、红砂岩在三维动静组合加载下,当轴压一定时,单位体积吸收能随围压的增大表现出先增大后降低的规律;当围压一定时,单位体积吸收能随轴压的增大也表现出先增大后降低的规律;单位体积吸收能、入射能与平均应变率均呈现出线性递增关系,并有良好的线性相关拟合性。5、红砂岩在三维动静组合加载下,红砂岩的破坏程度随应变率的增大而增大;当轴压一定时,红砂岩的破坏程度随围压的增大而降低;当围压一定时,红砂岩的破坏程度随轴压的增大而增大;在无围压时,岩石呈现出“X”型或“双锥”型的压剪破坏模式;在三维动静组合加载下,岩石呈现出圆锥体或圆锥台型的压剪破坏模式。6、三维动静组合加载下红砂岩动力响应的试验结果和规律,认识到“岩石在储存大量弹性应变能且处于峰值强度状态,岩石是不稳定的,若此时受到外界因素的干扰,岩石则会失稳”这一重要结论。
[Abstract]:In order to study the dynamic characteristics of rock and the dynamic mechanism of rock burst, taking the red sandstone as the research object, using the improved Hopkinson pressure bar test device, the pre-loading three-dimensional Gao Jing stress and impact load test were carried out on the red sandstone. The dynamic characteristics of red sandstone, such as deformation, strength, energy dissipation and failure mode, are analyzed. The dynamic mechanism of rock burst is briefly analyzed. The results show that the stress-strain curve of red sandstone under uniaxial compression is divided into four stages: compaction stage, elastic stage and failure stage. There are three types of failure modes under uniaxial compression, which are tensile failure, The shear failure of single inclined plane is X-shaped conjugate inclined plane shear failure .2.The stress-strain curve of red sandstone under three-dimensional dynamic and dynamic combination loading has only three stages compared with uniaxial compression, which are elastic stage, failure development stage and post-failure stage, respectively. The stress-strain curves of red sandstone show three types of strain springback, stress drop and post-peak plasticity at different strain rates. The Secant modulus increases with the increase of confining pressure, and the Secant modulus increases first and then decreases with the increase of confining pressure. When the confining pressure is constant, with the increase of axial pressure, the dynamic compressive strength of red sandstone increases with the increase of confining pressure, and with the increase of confining pressure, the dynamic compressive strength of red sandstone increases with the increase of confining pressure under the loading of three-dimensional dynamic and dynamic combination, and when the confining pressure is constant, the dynamic compressive strength of red sandstone increases with the increase of confining pressure. The dynamic compressive strength of red sandstone increases firstly and then decreases with the increase of axial compression. The dynamic compressive strength growth factor of red sandstone increases linearly with strain rate 1/3 under three dimensional dynamic and dynamic combination loading. There is good linear correlation fitting. 4. Under the loading of 3D dynamic and dynamic combination, the unit volume absorption energy of red sandstone increases first and then decreases with the increase of confining pressure, when axial pressure is fixed, the absorption energy of red sandstone increases first and then decreases with the increase of confining pressure. The absorption energy of unit volume increases first and then decreases with the increase of axial pressure, and the absorption energy, incident energy and average strain rate of unit volume increase linearly. The failure degree of red sandstone increases with the increase of strain rate, and decreases with the increase of confining pressure when axial compression is fixed. When the confining pressure is fixed, the failure degree of red sandstone increases with the increase of axial pressure, and when the confining pressure is no confining pressure, the rock presents a compression shear failure mode of "X" type or "double cone" type, and under three-dimensional dynamic and dynamic combination loading, the failure degree of red sandstone increases with the increase of axial pressure. The rock presents the compressive shear failure mode of cone or cone table. The experimental results and rules of dynamic response of red sandstone under three dimensional dynamic and dynamic combination loading show that "the rock is storing a lot of elastic strain energy and is in the state of peak strength." Rock is unstable, and if disturbed by external factors, rock will be unstable.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD315

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