Pendulum-type ( μ wave) wave is a new type of elastic wave propagated with low frequency and low velocity in deep block rock masses. The μ wave is sharply different from the traditional longitudinal and transverse w...Pendulum-type ( μ wave) wave is a new type of elastic wave propagated with low frequency and low velocity in deep block rock masses. The μ wave is sharply different from the traditional longitudinal and transverse waves propagated in continuum media and is also a phenomenon of the sign-variable reaction of deep block rock masses to dynamic actions, besides the Anomalous Low Friction (ALF) phenomenon. In order to confirm the existence of the μ wave and study the rule of variation of this μ wave experimentally and theoretically, we first carried out one-dimensional low-speed impact experiments on granite and cement mortar blocks and continuum block models with different characteristic dimensions, based on the multipurpose testing system developed by us independently. The effects of model material and dimensions of models on the propagation properties of 1D stress wave in blocks medium are discussed. Based on a comparison and analysis of the propagation properties (acceleration amplitudes and Fourier spectra) of stress wave in these models, we conclude that the fractures in rock mass have considerable effect on the attenuation of the stress wave and retardarce of high frequency waves. We compared our model test data with the data of in-situ measurements from deep mines in Russia and their conclusions. The low-frequency waves occurring in blocks models were validated as Pendulum-type wave. The frequencies corresponding to local maxima of spectral density curves of three-directional acceleration satisfied several canonical sequences with the multiple of 2～(1/2), most of those frequencies satisfied the quantitative expression (2～(1/2))i V p/2△ .展开更多
The quasi-periodic pendulum type equations are considered. A sufficient and necessary condition of Lagrange stability for this kind of equations is obtained. The result obtained answers a problem proposed by Moser und...The quasi-periodic pendulum type equations are considered. A sufficient and necessary condition of Lagrange stability for this kind of equations is obtained. The result obtained answers a problem proposed by Moser under the quasi-periodic case.展开更多
Constructive disposition principles of the basic optical units of Michelson interferometers are used in making one-coordinate laser strainmeters of unequal-arm type. The fundamental advantages of pendulurn-type laser ...Constructive disposition principles of the basic optical units of Michelson interferometers are used in making one-coordinate laser strainmeters of unequal-arm type. The fundamental advantages of pendulurn-type laser strainmeter more than classical-type laser strainmeter are displayed.展开更多
深部岩体具有块系等级构造特性,俄罗斯深部矿山原位量测得到的摆型波(μ波)产生于动力冲击作用下(如深部地震、岩爆和封闭核爆等)块系岩体的运动,是一种不同于传统纵波和横波的新型非线性弹性波。为了证明μ波的存在,并对块系块体介质...深部岩体具有块系等级构造特性,俄罗斯深部矿山原位量测得到的摆型波(μ波)产生于动力冲击作用下(如深部地震、岩爆和封闭核爆等)块系岩体的运动,是一种不同于传统纵波和横波的新型非线性弹性波。为了证明μ波的存在,并对块系块体介质中应力波传播特性及块体材料、尺寸和结构形式的影响进行研究,利用自主研发的深部岩体动态特性试验系统,分别对6种具有不同特征尺寸的花岗岩和水泥砂浆块系块体模型和连续块体模型进行一维低速冲击试验。试验表明:对于两种结构形式的介质,一维冲击作用下,块体(测点)三向加速度幅值均随冲击能量提高近似线性增加。对于块系块体介质,块体三向加速度幅值随块体个数增加呈一阶指数衰减,并且衰减系数与冲击能量无关;冲击能量仅仅改变加速度波谱密度幅值,而对三向振动极值频率没有影响,并且块体越多,能量越大,块体振动波谱趋于低频波的趋势越强;通过对比试验结果和原位量测结论(关于μ波无量纲冲击能量判据,波速和振幅,波谱峰值频率等),证明了块系介质中出现的低频低速波就是μ波;通过对5种块系块体模型三向加速度频谱进行分析,证明其振动极值频率满足定量的规范序列关系(2^(1/2))i f 0,推广了原位测量试验结论。并且上述规律中,块体材料和尺寸效应不明显,而对于连续块体介质上述规律均不成立。最后,分别采用黏弹性夹层和刚性块体、集中质点以及弹性块体三种理论计算模型对冲击作用下块系块体运动参数进行分析,计算结果和试验曲线吻合较好,并讨论了夹层参数的敏感性。展开更多
基金Projects 50525825 and 90815010 supported by the National Natural Science Foundation of China2009CB724608 by the National Basic Research Program of ChinaBK2008002 by the Natural Science Foundation of Jiangsu Province
文摘Pendulum-type ( μ wave) wave is a new type of elastic wave propagated with low frequency and low velocity in deep block rock masses. The μ wave is sharply different from the traditional longitudinal and transverse waves propagated in continuum media and is also a phenomenon of the sign-variable reaction of deep block rock masses to dynamic actions, besides the Anomalous Low Friction (ALF) phenomenon. In order to confirm the existence of the μ wave and study the rule of variation of this μ wave experimentally and theoretically, we first carried out one-dimensional low-speed impact experiments on granite and cement mortar blocks and continuum block models with different characteristic dimensions, based on the multipurpose testing system developed by us independently. The effects of model material and dimensions of models on the propagation properties of 1D stress wave in blocks medium are discussed. Based on a comparison and analysis of the propagation properties (acceleration amplitudes and Fourier spectra) of stress wave in these models, we conclude that the fractures in rock mass have considerable effect on the attenuation of the stress wave and retardarce of high frequency waves. We compared our model test data with the data of in-situ measurements from deep mines in Russia and their conclusions. The low-frequency waves occurring in blocks models were validated as Pendulum-type wave. The frequencies corresponding to local maxima of spectral density curves of three-directional acceleration satisfied several canonical sequences with the multiple of 2～(1/2), most of those frequencies satisfied the quantitative expression (2～(1/2))i V p/2△ .
基金Partially supported by the NSF (10871203, 10601019) of Chinathe NCET (07-0386)of China
文摘The quasi-periodic pendulum type equations are considered. A sufficient and necessary condition of Lagrange stability for this kind of equations is obtained. The result obtained answers a problem proposed by Moser under the quasi-periodic case.
基金supported financially in part by the Russian Science Foundation(RSF)(Grant No.14-17-00041)
文摘Constructive disposition principles of the basic optical units of Michelson interferometers are used in making one-coordinate laser strainmeters of unequal-arm type. The fundamental advantages of pendulurn-type laser strainmeter more than classical-type laser strainmeter are displayed.
文摘深部岩体具有块系等级构造特性,俄罗斯深部矿山原位量测得到的摆型波(μ波)产生于动力冲击作用下(如深部地震、岩爆和封闭核爆等)块系岩体的运动,是一种不同于传统纵波和横波的新型非线性弹性波。为了证明μ波的存在,并对块系块体介质中应力波传播特性及块体材料、尺寸和结构形式的影响进行研究,利用自主研发的深部岩体动态特性试验系统,分别对6种具有不同特征尺寸的花岗岩和水泥砂浆块系块体模型和连续块体模型进行一维低速冲击试验。试验表明:对于两种结构形式的介质,一维冲击作用下,块体(测点)三向加速度幅值均随冲击能量提高近似线性增加。对于块系块体介质,块体三向加速度幅值随块体个数增加呈一阶指数衰减,并且衰减系数与冲击能量无关;冲击能量仅仅改变加速度波谱密度幅值,而对三向振动极值频率没有影响,并且块体越多,能量越大,块体振动波谱趋于低频波的趋势越强;通过对比试验结果和原位量测结论(关于μ波无量纲冲击能量判据,波速和振幅,波谱峰值频率等),证明了块系介质中出现的低频低速波就是μ波;通过对5种块系块体模型三向加速度频谱进行分析,证明其振动极值频率满足定量的规范序列关系(2^(1/2))i f 0,推广了原位测量试验结论。并且上述规律中,块体材料和尺寸效应不明显,而对于连续块体介质上述规律均不成立。最后,分别采用黏弹性夹层和刚性块体、集中质点以及弹性块体三种理论计算模型对冲击作用下块系块体运动参数进行分析,计算结果和试验曲线吻合较好,并讨论了夹层参数的敏感性。
