节理岩体力学参数的波动测试法

发布时间：2018-03-22 11:02

本文选题：节理岩体　切入点：波形变化　出处：《江西理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：当前我国经济建设发展迅猛,基础建设如高速公路、铁路、工业与民用建筑、水利水电等工程中会遇到复杂的岩体,准确获取岩体力学参数对工程设计、施工以及建设维稳有着重要作用,为此开展应力波在岩体中的传播规律研究,提出节理岩体力学参数测试方法,该研究成果为快捷测试工程岩体变形参数提供了途径。本文针对不同尺度的节理岩体,提出相应的力学参数测试法,在江西德兴铜矿进行现场试验,测试了节理岩体力学参数。针对实际工程大尺度节理岩体参数难以测试,将节理岩体等效为Kelvin介质,采用岩体内钻孔爆破产生应力波、地表接收震动信号试验方案,分析应力波在岩体的传播过程,提出基于应力波时空衰减规律测试节理岩体参数方法,测试结果为:节理岩体黏性系数为2.18 MPa?s,动态弹性模量为2.52 GPa;采用钻孔弹模仪原位测试节理岩体静态弹性模量为1.58 GPa,动态弹性模量是静态弹性模量的1.6倍。选取厚度较小的节理为研究对象,将节理等效为标准线性固体模型,研究应力波在节理岩体的传播规律,提出基于波形变化规律测试节理法向刚度、法向黏性系数的方法。研究结果表明:节理具有低通滤波特性;波形变化系数随着法向刚度、法向黏性系数的增加而减小;现场试验测试节理参数时,子波有效频率范围为800~1200 Hz,采用波形变化系数量化入射侧计算波形与实测波形差异时,测试节理法向刚度为1.03 GPa/m,法向黏性系数为5.7 MPa?s。针对力学参数渐变型软弱夹层,将其抽象为损伤度按照二次曲线规律变化的介质,建立应力波在软弱夹层的传播模型,提出软弱夹层弹性模量测试方法。研究结果表明:采用波形变化系数量化入射侧计算波形与实测波形差异时,随夹层峰值损伤度的增加,波形变化系数先减小后增加;波形变化系数达到最小值时,确定夹层峰值弹性模量为2.14 GPa;随子波主频的增加,夹层动态峰值弹性模量近似线性增加,线性拟合得静态峰值弹性模量为0.74 GPa;基于变形相等原则计算夹层的等效弹性模量为4.24 GPa。
[Abstract]:At present, the economic construction of our country is developing rapidly, and the basic construction such as highway, railway, industrial and civil buildings, water conservancy and hydropower projects will encounter complex rock mass, and accurately obtain the mechanical parameters of rock mass to the engineering design. Construction and construction stability play an important role. For this reason, the propagation law of stress wave in rock mass is studied, and the testing method of mechanical parameters of jointed rock mass is put forward. The research results provide a way to quickly test the deformation parameters of engineering rock mass. In this paper, the corresponding mechanical parameters test method is proposed for different scales of jointed rock mass, and the field test is carried out in Dexing Copper Mine, Jiangxi Province. The mechanical parameters of jointed rock mass are tested. In view of the difficulty of testing large-scale jointed rock mass parameters in practical engineering, the jointed rock mass is equivalent to Kelvin medium, the stress wave is produced by drilling blasting in rock body, and the ground surface receives vibration signal test scheme. By analyzing the propagation process of stress wave in rock mass, a method for measuring the parameters of jointed rock mass based on the law of space-time attenuation of stress wave is proposed. The results are as follows: viscosity coefficient of jointed rock mass is 2.18 MPA? S, dynamic elastic modulus is 2.52 GPa, static elastic modulus of jointed rock mass measured by drilling elastic modulus instrument is 1.58 GPA, dynamic elastic modulus is 1.6 times of static elastic modulus. The joint is equivalent to a standard linear solid model, and the propagation law of stress wave in jointed rock mass is studied. Method of normal viscosity coefficient. The results show that the joint has the characteristics of low pass filtering, the variation coefficient of waveform decreases with the increase of normal stiffness and the normal viscosity coefficient. The effective frequency range of wavelet is 800 ~ 1200Hz.When the waveform variation coefficient is used to quantify the difference between the incident side and the measured waveform, the normal stiffness of the test joint is 1.03 GPA / m, and the normal viscosity coefficient is 5.7 MPA? S. Aiming at the mechanical parameter gradual change type weak intercalation, the stress wave propagation model in the weak intercalation is established by abstracting it as a medium in which the damage degree changes according to the law of quadratic curve. The test method of elastic modulus of weak intercalation is put forward. The results show that the waveform variation coefficient decreases first and then increases with the increase of the damage degree of the intercalation when the wave form is calculated by using the waveform variation coefficient quantifying the incident side to calculate the difference between the waveform and the measured waveform. The peak elastic modulus of the interlayer is determined to be 2.14 GPA when the waveform variation coefficient reaches the minimum value, and the dynamic peak elastic modulus increases linearly with the increase of the main frequency of the wavelet. The linear fitting results show that the static peak elastic modulus is 0.74 GPA and the equivalent elastic modulus based on the principle of deformation equality is 4.24 GPa.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU45

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