共查询到20条相似文献，搜索用时 15 毫秒
1.
Analytical study of ground motion caused by seismic wave propagation across faulted rock masses 
下载免费PDF全文
下载免费PDF全文 Studying seismic wave propagation across rock masses and the induced ground motion is an important topic, which receives considerable attention in design and construction of underground cavern/tunnel constructions and mining activities. The current study investigates wave propagation across a rock mass with one fault and the induced ground motion using a recursive approach. The rocks beside the fault are assumed as viscoelastic media with seismic quality factors, Qp and Qs. Two kinds of interactions between stress waves and a discontinuity and between stress waves and a free surface are analyzed, respectively. As the result of the wave superposition, the mathematical expressions for induced ground vibration are deduced. The proposed approach is then compared with the existing analysis for special cases. Finally, parametric studies are carried out, which includes the influences of fault stiffness, incident angle, and frequency of incident waves on the peak particle velocities of the ground motions. 相似文献
2.
矿山工程地质中往往存在断层和采空区,微震信号传播经过断层和采空区时,其传播规律必然会发生改变,因此研究特殊地质结构微震信号传播规律具有重要意义。基于惠更斯原理,考虑不同层状岩体中微震波传播速度不同,建立了非均匀介质条件下微震波的波面方程,进而获得波面半径与入射角之间的关系。结合室内相似材料模型实验,验证了波面方程的适用性,同时总结了断层、采空区对微震信号传播的影响特征。研究结果表明：微震信号穿过断层的用时更长,断层的存在导致信号的能量（最大振速）发生较大幅度的衰减;微震信号穿过断层后会以原来的速度继续传播,信号能量的衰减并不会使微震信号的传播速度发生衰减;微震波穿过断层时的入射角越大,穿过断层的用时越长,信号的能量衰减越多;采空区的存在导致微震信号的传播速度发生衰减,震源与监测点之间的距离越近,采空区对微震信号相对传播速度的影响越大。 相似文献
3.
Tingting Liu Xinpin Li Jianchun Li Haibo Li Yun Zheng Yi Luo 《Arabian Journal of Geosciences》2017,10(11):249
This paper presents a numerical simulation of S-wave propagation across a rough, filled discontinuity using the universal distinct element code (UDEC). The ability of UDEC to simulate a stress wave across a smooth and planar discontinuity filled with an elastic material is validated through comparisons with analytical solutions. Next, the effect of the plastic deformation of the fill on the wave propagation is investigated. The model is extended to further study S-wave propagation across a filled discontinuity with rough interfaces, which is described using a sawtooth. The transmission coefficient defined by the energy is used to measure the wave attenuation. Finally, a parametric study is conducted to investigate the influences of the filled thickness, asperity angle, and incident amplitude on the transmission waves and transmission coefficients. The asperity angle and filled thickness together determine the transmitted waveform and transmission coefficient. The transmitted wave may be cut off when the incident wave amplitude exceeds a threshold value. The transmission coefficient decreases with a different trend with the incident wave amplitude increasing when the asperity angle varies. Compared with planar discontinuity, a filled discontinuity with rough interfaces is more sensitive to the amplitude of the incident wave. The causes of these phenomena are analyzed in detail. In addition, the deformation of the fill material is strongly related to the wave attenuation. 相似文献
4.
夹层是常见的地质结构,在地震或爆破荷载作用下,夹层对应力波的传播以及对岩体的响应具有重要的影响。以往对应力波在夹层介质中传播的研究多集中于夹层对应力波的隔振或透射性能,而对应力波在夹层中的多次折、反射过程中能量的演化规律缺乏讨论,对夹层介质的应力响应与破坏没有开展较好地分析。通过理论方法对应力波在夹层内部传播过程中的能量系数的变化规律进行了研究,分析了岩体介质波阻抗和应力波入射角对夹层内外介质中累积波动能量系数的影响规律,以及平面型边坡中软弱夹层的应力响应特征和动态稳定性。研究发现,应力波在夹层内部往复反射过程中,夹层内剩余应力波能量随折、反射发生次数呈指数曲线下降,第4次折、反射后产生的应力波能量可以忽略;夹层内外介质中应力波的累积能量系数的差异随着夹层内外介质波阻抗的相对差异的增大而增大。在平面谐波入射下,边坡内部的夹层中的剪应力和抗剪强度呈波动变化;相对P波,SV波入射会产生较高水平的剪应力,对边坡稳定性影响最大。且SV波入射时,边坡的安全系数对夹层的倾角变化更为敏感,随倾角增大而迅速降低。 相似文献
5.
Analysis of Blast Wave Interaction with a Rock Joint 总被引：8，自引：3，他引：5
The interaction between rock joints and blast waves is crucial in rock engineering when rock mass is suffered from artificial or accidental explosions, bursts or weapon attacks. Based on the conservation of momentum at the wave fronts and the displacement discontinuity method, quantitative analysis for the interaction between obliquely incident P- or S-blast wave and a linear elastic rock joint is carried out in the present study, so as to deduce a wave propagation equation. For some special cases, such as normal or tangential incidence, rigid or weak joint, the analytical solution of the stress wave interaction with a rock joint is obtained by simplifying the wave propagation equation. By verification, it is found that the transmission and reflection coefficients from the wave propagation equation agree very well with the existing results. Parametric studies are then conducted to evaluate the effects of the joint stiffness and incident waves on wave transmission and reflection. The wave propagation equation derived in the present study can be straightforwardly extended for different incident waveforms and nonlinear rock joints to calculate the transmitted and reflected waves without mathematical methods such as the Fourier and inverse Fourier transforms. 相似文献
6.
Analysis of Wave Propagation Through a Filled Rock Joint 总被引：1，自引：1，他引：0
An analytical and experimental study on a longitudinal wave (P-wave) transmission normally across a filled rock joint is presented in this paper. The dynamic property of the filling material for the artificial rock joints is derived from a series of modified split Hopkinson pressure bar (SHPB) tests. The incident and transmitted waves in granitic pressure bars are calculated by wave separations of the strain gauge readings. The incident wave is approximated by a series of half-sinusoidal waves, and an analytical model on wave propagation across a filled rock joint is then deduced. The derived wave transmission coefficients across the filled joint agree very well with those from the test results. Both the analytical and test results show that the wave transmission coefficients are influenced by the mechanical properties and the input energy of the incident waves. Analytical parametric studies with respect to pre-compaction of the filling material, the frequency and amplitude of the incident wave have also been conducted. 相似文献
7.
Mohd Mustaqim Mohd-Nordin Ki-Il Song Gye-Chun Cho Zainab Mohamed 《Rock Mechanics and Rock Engineering》2014,47(2):561-573
Geophysical site investigation techniques based on elastic waves have been widely used to characterize rock masses. However, characterizing jointed rock masses by using such techniques remains challenging because of a lack of knowledge about elastic wave propagation in multi-jointed rock masses. In this paper, the roughness of naturally fractured rock joint surfaces is estimated by using a three-dimensional (3D) image-processing technique. The classification of the joint roughness coefficient (JRC) is enhanced by introducing the scan line technique. The peak-to-valley height is selected as a key indicator for JRC classification. Long-wavelength P-wave and torsional S-wave propagation across rock masses containing naturally fractured joints are simulated through the quasi-static resonant column (QSRC) test. In general, as the JRC increases, the S-wave velocity increases within the range of stress levels considered in this paper, whereas the P-wave velocity and the damping ratio of the shear wave decrease. In particular, the two-dimensional joint specimen underestimates the S-wave velocity while overestimating the P-wave velocity. This suggests that 3D joint surfaces should be implicated to obtain the reliable elastic wave velocity in jointed rock masses. The contact characteristic and degree of roughness and waviness of the joint surface are identified as a factor influencing P-wave and S-wave propagation in multi-jointed rock masses. The results indicate a need for a better understanding of the sensitivity of contact area alterations to the elastic wave velocity induced by changes in normal stress. This paper’s framework can be a reference for future research on elastic wave propagation in naturally multi-jointed rock masses. 相似文献
8.
盾构隧道衬砌由于各种类型接头的存在而与整体式衬砌的力学特性存在较大差异。将盾构隧道衬砌结构看作由弹塑性铰链连接的刚性管片组成,考虑围岩介质的黏弹性,提出了爆炸地震波作用下盾构隧道动力分析的简化计算方法。采用该方法对南京地铁盾构段典型横断面进行了动力分析,研究了爆炸地震波入射角度、围岩介质特性及管片厚度对结构受力与变形的影响规律。分析结果表明:波入射角度对盾构隧道有很大影响,斜入射时结构的动力响应要大于垂直入射时结构的动力响应;围岩介质等级越高,围岩对隧道结构的约束越强,隧道的抗爆性能越好;管片厚度的增大会增大结构的内力,合理设置管片厚度有利于提高盾构隧道抗爆性能。 相似文献
9.
笔者给出了一种能够模拟弹性波在任意各向异性介质中传播的二维三分量高阶有限差分算法.相对于常规交错网格有限差分方法,旋转交错网格有限差分方法在介质具有强差异性时能更精确地模拟地震波的传播,避免常规交错网格中因对弹性系数进行插值而带来的误差.采用高阶旋转交错网格有限差分方法模拟并分析了零偏移距横波分裂现象随裂缝介质方位角和倾角变化的响应特征.结果表明:结合完全匹配层(PML)吸收边界条件的高阶旋转交错网格有限差分方法能获得高精度的地震波场模拟数据,并且在边界具有良好的吸收效果;横波分裂现象主要受裂缝走向与波的极化方向之间的夹角影响,受裂缝倾角影响较小,且快慢横波的能量也跟裂缝走向与波极化方向间的夹角有关.具有倾斜对称轴的横向各向同性(TTI)介质倾角的变化可能会导致记录中波到达时的变化,影响快慢横波的时差.利用横波分裂的能量分布和方位各向异性特征,可以帮助检测裂缝的方位角和倾角.横波在多层TTI介质中传播时会发生多次分裂的现象. 相似文献
10.
地震作用下山体边坡的动力响应规律与地震波入射角度显著相关,本文基于间接边界元方法研究SH波倾斜入射下边坡的动力响应特征.基于间接边界元理论研发了用于边坡岩体动力响应分析的边界元程序,通过计算平直裂隙对弹性波的反射及散射波波场对程序进行验证,并详细探讨了不同类型的边坡在各种入射角度的应力波作用下的响应特性.SH波铅直向入射时,半圆形凹陷地形的谷肩位置地震动振幅最小,而半圆形凸起地形的最高点位置振幅最大,单面坡的坡肩位置地震动最大,楔形凸起地形的坡顶地震动最强烈;当SH波入射角增大,各类边坡的最大地震动力响应位置也有所偏移,地震放大系数亦随之变化;以樟木镇边坡为实例揭示了复杂形态边坡岩体中的局部凸起对地震动的放大作用.研究结果表明,边坡微地形特征对地震动力响应影响非常大,凸起山体坡顶的动力放大效应最为显著;同一边坡在不同入射角地震波作用下产生的动力放大系数以及发生的位置不同.本文的研究结果对评价坡体稳定性和边坡工程抗震防设等具有重要的指导意义. 相似文献
11.
基于近场波动有限元方法并结合黏弹性人工边界条件,针对3D断层场地,通过求解等效二维场地地震响应,从而获得3D场地地震动输入的自由场响应,并将自由场响应转化为3D模型边界面上的等效节点力,从而建立含断层3D场地P波入射的倾斜输入方法。自由场算例验证所提方法具有较好精度,进而基于建立的输入方法,开展了跨断层隧道地震响应的数值模拟研究。数值模拟结果表明:在P波作用下,隧道跨断层部位处于拉、压、剪切的复杂受力状态,且断层处的隧道衬砌地震响应明显大于其他部位的地震响应;围岩的力学性质与断层的力学性质相差越大,断层处衬砌的地震响应放大越明显;断层处衬砌地震响应随断层深度的增加而增加。另外,跨断层隧道的地震响应受P波入射角度的影响较大,随P波入射角度的增加,断层处隧道衬砌的轴力、弯矩先增加后减小,而剪力具有逐渐减小的规律。 相似文献
12.
Xuhui Zheng Jinzhong Sun Leihua Yao Lei Liu Anyang Shao 《Environmental Earth Sciences》2018,77(14):528
This paper presents a three-dimensional oblique incidence method based on stress time-history functions of seismic body waves. This method realizes the three-dimensional oblique incidence of a single body wave phase or superposed multiple phases, which considers the earthquake action in the analysis of the slope seismic response. To implement this method, first, the spatial relationship between slope and incident seismic wave rays is described, and the direction of incident seismic waves is defined with two parameters: the azimuth angle \(\alpha\), which reflects the azimuth of epicenter; and the incident angle \(\theta\), which is a concentrated expression of the hypocentral depth and epicentral distance. Second, at the bottom boundary of the slope numerical model, the vibration starting time of each node excited by an oblique incident seismic wave is calculated. By considering vibration time sequence, the successive disturbance of rock and soil medium at the bottom of the slope is achieved. Then the stress time-history functions of six body wave phases are derived. Numerical simulation results of the x demonstrate the effectiveness, applicability and necessity of the proposed method. 相似文献
13.
依据弹性波理论,应力波斜入射线弹性节理时会发生波场分解。根据入射、透射及反射各波形的不同到时,运用离散元软件UDEC模拟应力波在含倾斜节理岩体中的传播并计算其透射、反射系数,并分析其波型转换规律。应力波斜入射单节理时,模拟得到的透射、反射系数随节理刚度、入射角度的变化规律,与已有的理论解是吻合的。应力波斜入射一组平行节理时,随着节理间距的增大,其同类波的透射系数Tpp、Tss先增大后减小,最后趋于稳定值;节理条数越多,Tpp、Tss越小。此外,不同条数的节理,透射系数达到最大值的临界节理间距值基本一致,但趋于稳定时的节理间距值随节理条数的增加而逐渐增大。 相似文献
14.
The estimation of wave transmission across the fractured rock masses is of great importance for rock engineers to assess the stability of rock slopes in open pit mines. Presence of fault, as a major discontinuity, in the jointed rock mass can significantly impact on the peak particle velocity and transmission of blast waves, particularly where a fault contains a thick infilling with weak mechanical properties. This paper aims to study the effect of fault properties on transmission of blasting waves using the distinct element method. First, a validation study was carried out on the wave transmission across a single joint and different rock mediums through undertaking a comparative study against analytical models. Then, the transmission of blast wave across a fault with thick infilling in the Golgohar iron mine, Iran, was numerically studied, and the results were compared with the field measurements. The blast wave was numerically simulated using a hybrid finite element and finite difference code which then the outcome was used as the input for the distinct element method analysis. The measured uplift of hanging wall, as a result of wave transmission across the fault, in the numerical model agrees well with the recorded field measurement. Finally, the validated numerical model was used to study the effect of fault properties on wave transmission. It was found that the fault inclination angle is the most effective parameter on the peak particle velocity and uplift. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
15.
为分析采动地震波煤岩响应及其波场特性,构建顶板岩层和煤层2种传播介质接收采动地震波的多通道微震监测系统,研究2种介质采动地震波的传播和衰减特征。研究结果表明：顶板岩层接收到采动地震波的平均波速、加速度均高于煤层,2种介质中的地震波加速度均与爆破装药量成正相关,与传播距离、介质密度负相关。采动微地震波能量、信号时长随传播距离分别呈指数、线性衰减,近爆心处煤层传播微地震波能量、信号时长均高于顶板,超过一定距离后顶板高于煤层;采动微地震波传播距离有限,顶板的有效传播距离高于煤层,地震波有效传播距离与爆破装药量线性正相关。采动地震波低频部分的品质因子高于高频部分,顶板岩层的品质因子高于煤层。研究成果有助于地震波传播介质选取、检波器布设优化。 相似文献
16.
In rock engineering, the damage criteria of the rock mass under dynamic loads are generally governed by the threshold values of wave amplitudes, such as the peak particle velocity and the peak particle acceleration. Therefore, the prediction of wave attenuation across fractured rock mass is important on assessing the stability and damage of rock mass under dynamic loads. This paper aims to investigate the applications of the discontinuous deformation analysis (DDA) for modeling wave propagation problems in rock mass. Parametric studies are carried out to obtain an insight into the influencing factors on the accuracy of wave propagations, in terms of the block size, the boundary condition and the incident wave frequency. The reflected and transmitted waves from the interface between two materials are also numerically simulated. To study the tensile failure induced by the reflected wave, the spalling phenomena are modeled under various loading frequencies. The numerical results show that the DDA is capable of modeling the wave propagation in jointed rock mass with a good accuracy. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
17.
浅层地震勘探在工程领域广泛应用,但在岩溶地域,由于覆盖层与中—弱风化岩石层之间存在明显的波阻抗分解面,入射波的大部分能量被约束在覆盖层中,从而难以在基岩中形成有效激励的弹性波,以至难以准确探测基岩体内的溶洞、断层等异常的响应。以两层简化模型模拟该类地层结构,通过波动方程的解析计算,发现基岩表面的能量透射规律,从理论上说明在浅层乃至超浅层地震勘探中,选择小偏移距和临界角附近横波SV测量的可能性,通过各种因素的综合考虑,力争获得目的体的最大响应信号。 相似文献
18.
Jun Wang Jie Liu Qiao Liang Xiangsen Ouyang 《Geotechnical and Geological Engineering》2018,36(4):1991-2001
In the soil slope supported by bolts, longitude waves instead of transverse waves, generated by earthquakes, first reach the slope surface. With the dynamic response of the P (pressure) wave along the anchorage structure, first, a theoretical study was conducted to investigate the propagation characteristics of the interference superposition, generated by the SV (shear-vertical) and the P waves. The SV wave was formed by the wave, originating from the bottom and reflected from the free surface of the slope, whereas the latter was the incident P wave, propagating in the slope. In addition, the structural measures, restraining the seismic wave, and the characteristics of the restraint effect at the free segment of the bolt were investigated. According to the wave-way difference between the incident P wave and the reflected SV wave, the minimum critical slope angle, influenced by the interference at the shallow slope, and the maximum influencing depth of the dynamic response, acting vertically to the slope surface, were obtained. The results indicate that the maximum influencing depth linearly correlated with the slope angle. Furthermore, based on the propagation characteristics of the P wave along the bolt, and the coupled relation between the wave length and the anchorage design parameters, the axial acceleration of the wave propagating along the bolt axis was obtained. Then, the theoretical length of the anti-seismic bolt, subjected to seismic waves, and the compensation force of the anchorage structure were obtained. Finally, a numerical study, based on FlAC3D, properly verified the theoretical conclusions. 相似文献
19.
众多城市坐落于沉积河谷之中,沉积河谷-密集建筑群间的地震动力相互作用规律尚不明确。采用间接边界元方法（IBEM）,对在平面SV波入射下,沉积河谷-建筑群之间的地震相互作用进行二维模拟计算和参数分析。研究结果表明：沉积河谷-建筑群间存在着显著而复杂的地震动力相互作用;较浅沉积河谷中建筑群地震响应呈现强弱交替变换特征;入射波角度、沉积河谷的材料、几何特征是影响沉积河谷-建筑群整体地震响应规律的关键因素。总体上看,建筑群对浅沉积河谷地震动响应有较大的降幅效应,特别是高频波入射下最大降幅近50%。实际河谷地震放大效应评估需考虑密集建筑群的影响,而位于地震波聚焦位置的建筑物需适当提高设防标准。 相似文献
20.
海原断裂带断层通道波观测与破碎带宽度 总被引：5，自引：0，他引：5
断层通道波是低速断层破碎带与高速围岩之间的边界相干多重反射形成的,其振幅和频率强烈依赖于断层的几何形态和物理性质,故能用于探测断裂带的内部结构.在宁夏海原西安州附近海原断裂带上,横跨1920年海原8.6级地震地表破裂带布设2条测线,接收测线之间人工爆破激发的断层通道波.每条测线由1台3分量数字地震仪组成,靠近破裂带台间距30～40 m,远离破裂带台间距增大至230～250 m.对测线1的台站接收到的一炮垂直道地震波数据进行了0.1～4.0 Hz频段的滤波,结果表明在S波到时之后存在多组强振幅、低频率、长波链的断层通道波.由断层通道波揭示的海原断裂带在西安州附近的断裂破碎带宽度约为250 m. 相似文献