不同含水率红砂岩单轴受压状态下超声波参数变化规律研究
发布时间：2019-01-23 13:08
【摘要】：岩体介质超声波测试技术是近四十多年发展起来的一种新技术,它通过测定超声波穿透岩体后声波信号的声学参数的变化,间接地了解岩石或岩体的物理力学特性、结构构造特征及应力状态,已得到国内外岩土工程界的广泛重视。岩石在单轴受压过程中内部会产生破坏,根据超声波参数特征可以判断岩样受压过程中所处状态,从而对岩石的弹性极限以及应力应变特征的研究提供了更多的参考意义。本文主要通过对不同含水饱和度的红砂岩在单轴加载过程中进行超声波测试,研究不同含水率岩石在单轴加载条件下超声波的传播特性,实验通过对岩石应力应变曲线以及超声波参数的分析,研究饱水度对岩石强度和声波参数的影响、岩石的弹性特征等。研究结果表明:(1)岩石声波波速随压力增大先增大后减小。这是由于在低压时岩石内部小的孔隙易于闭合,当大量的孔隙闭合时,声波波速会出现明显的增大现象;随着压力增加,闭合的孔隙重新张开、新的微裂隙的产生并扩展使得波速出现减小。(2)岩石饱水度对岩石物理力学性质影响很大,随着岩石含水率增加,其抗压强度呈非线性减小。岩石饱水过程中,岩石矿物颗粒表面和孔壁的吸附水对岩样的弹性模量和强度影响较大,也即水 岩作用导致的岩石矿物颗粒软化、颗粒间联结减弱等劣化效应明显较大。(3)岩石含水率对声波参数的影响。岩样在自然饱水过程中,声波波速随岩样含水饱和度的增加而降低,从干燥状态至饱水度70%过程中,波速缓慢减小并且呈线性趋势,从饱水度70%至100%时,波速下降速度明显变快;声波波幅随岩样含水饱和度的增加出现先减小后增大的情况,可用二次函数进行拟合,从干燥状态至饱水度50%时,波幅出现明显下降,从饱水度50%至80%左右时,波幅达到最低值,从饱水度80%至100%时,波幅出现明显上升。
[Abstract]:Ultrasonic testing technology for rock mass media is a new technology developed in recent forty years. It can indirectly understand the physical and mechanical properties of rock or rock mass by measuring the change of acoustic parameters of acoustic signal after ultrasonic wave penetrating rock mass. Structural characteristics and stress state have been widely paid attention to in geotechnical engineering field at home and abroad. Rock will be destroyed in the process of uniaxial compression. According to the characteristics of ultrasonic parameters, the state of rock sample under compression can be judged, thus providing more reference significance for the study of elastic limit and stress-strain characteristics of rock. In this paper, the ultrasonic propagation characteristics of rocks with different moisture content under uniaxial loading are studied by ultrasonic testing of red sandstone with different water saturation during uniaxial loading. Through the analysis of stress-strain curves and ultrasonic parameters of rock, the influence of saturation degree on rock strength and acoustic wave parameters, and the elastic characteristics of rock are studied in the experiment. The results show that: (1) the velocity of rock acoustic wave increases first and then decreases with the increase of pressure. This is due to the fact that the small pores in the rock are easy to close at low pressure, and when a large number of pores are closed, the acoustic wave velocity will increase obviously. With the increase of pressure, the closed pores re-open, and the new microcracks appear and expand to reduce the wave velocity. (2) the saturation degree of rock has a great influence on the physical and mechanical properties of rock, and with the increase of water content of rock, The compressive strength is reduced in a nonlinear manner. In the process of saturated rock, the absorption water of rock mineral particle surface and pore wall has great influence on the elastic modulus and strength of rock sample, that is, the softening of rock mineral particle caused by water rock action. (3) the influence of rock water content on acoustic parameters. In the process of natural saturation, the acoustic wave velocity decreases with the increase of water saturation of rock samples. From dry state to 70% saturation, the wave velocity decreases slowly and linearly, from 70% to 100%. The decreasing speed of wave velocity becomes faster obviously. The amplitude of acoustic wave decreases first and then increases with the increase of water saturation of rock samples. It can be fitted by quadratic function. From the dry state to 50 degree of saturation, the amplitude of wave amplitude decreases obviously, and the amplitude decreases from 50% to 80%. The amplitude of the wave reached the lowest value, from 80% to 100%, the amplitude increased obviously.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD315
本文编号：2413803
[Abstract]:Ultrasonic testing technology for rock mass media is a new technology developed in recent forty years. It can indirectly understand the physical and mechanical properties of rock or rock mass by measuring the change of acoustic parameters of acoustic signal after ultrasonic wave penetrating rock mass. Structural characteristics and stress state have been widely paid attention to in geotechnical engineering field at home and abroad. Rock will be destroyed in the process of uniaxial compression. According to the characteristics of ultrasonic parameters, the state of rock sample under compression can be judged, thus providing more reference significance for the study of elastic limit and stress-strain characteristics of rock. In this paper, the ultrasonic propagation characteristics of rocks with different moisture content under uniaxial loading are studied by ultrasonic testing of red sandstone with different water saturation during uniaxial loading. Through the analysis of stress-strain curves and ultrasonic parameters of rock, the influence of saturation degree on rock strength and acoustic wave parameters, and the elastic characteristics of rock are studied in the experiment. The results show that: (1) the velocity of rock acoustic wave increases first and then decreases with the increase of pressure. This is due to the fact that the small pores in the rock are easy to close at low pressure, and when a large number of pores are closed, the acoustic wave velocity will increase obviously. With the increase of pressure, the closed pores re-open, and the new microcracks appear and expand to reduce the wave velocity. (2) the saturation degree of rock has a great influence on the physical and mechanical properties of rock, and with the increase of water content of rock, The compressive strength is reduced in a nonlinear manner. In the process of saturated rock, the absorption water of rock mineral particle surface and pore wall has great influence on the elastic modulus and strength of rock sample, that is, the softening of rock mineral particle caused by water rock action. (3) the influence of rock water content on acoustic parameters. In the process of natural saturation, the acoustic wave velocity decreases with the increase of water saturation of rock samples. From dry state to 70% saturation, the wave velocity decreases slowly and linearly, from 70% to 100%. The decreasing speed of wave velocity becomes faster obviously. The amplitude of acoustic wave decreases first and then increases with the increase of water saturation of rock samples. It can be fitted by quadratic function. From the dry state to 50 degree of saturation, the amplitude of wave amplitude decreases obviously, and the amplitude decreases from 50% to 80%. The amplitude of the wave reached the lowest value, from 80% to 100%, the amplitude increased obviously.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD315
【相似文献】
相关期刊论文 前6条
1 徐传枝;王旭光;马卉;;应变率下混凝土单轴受压本构关系试验研究[J];山西建筑;2012年05期
2 李祚华;李安;滕军;;基于能量的混凝土单轴受压塑性损伤本构模型[J];土木工程学报;2012年S2期
3 陈伟;彭刚;周寒清;;单轴受压状态下的混凝土力学特性研究[J];四川建筑科学研究;2014年01期
4 万小梅;苏卿;赵铁军;任心波;;单轴受压混凝土的微裂缝和氯离子侵入性[J];土木建筑与环境工程;2013年01期
5 林新 ,肖长富;复合岩石在单轴受压状态下的应力——应变全过程研究[J];湘潭矿业学院学报;1986年02期
6 ;[J];;年期
相关硕士学位论文 前1条
1 卜靖;不同含水率红砂岩单轴受压状态下超声波参数变化规律研究[D];中国矿业大学;2016年
，本文编号：2413803
本文链接：https://www.wllwen.com/kejilunwen/kuangye/2413803.html
