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1.
设想了一种两个自由度的滑块——弹簧模型，其中的2个滑块(滑块1和滑块2)由一根弹簧连接，并由一个慢慢移动的传动装置驱动。假设采用与速率和状态相关的摩擦定律，设定摩擦参数，使滑块1发生动态失稳。当摩擦参数接近稳定性转换点时，滑块2就会发生幕式无震滑动。在地震间隔期，当应力累积到大约稳态水平时，滑块2就开始缓慢滑动。随着振幅波动的衰减而成为稳态值，应力和滑动速度会发生准静态振荡。振荡衰减可能是自2001年以来日本东海地区观测到的幕式无震滑动的合理的产生机制。我们还在不同摩擦性质相互作用的双滑块模型的基础上，设想了板块边界上的各种滑动模式。 相似文献
2.
大陆地震的动力学模型研究 总被引：7，自引：2，他引：7
应用非线性动力学模型，以大陆构造构体为参照对象，对大陆地震的成组孕育和发生过程进行模拟研究，通过对６×８弹簧－滑块－阻尼器组合单元非线性动力学模型的理论计算及其结果的分析，得到了一系列与实际地震较类似的人工地震图像，如模型中的地震活动在时间上有轮回怀，在地点上有条带性，并在不同轮回中有条过移的现象。模型中应力变化十分复杂，但仍能为预测地震提供概略性的信息。 相似文献
3.
构造块体在球面上的运动及参数的确定 总被引：7，自引：2，他引：5
讨论了构造块体在球面上运动的两种运动学模型。其一称之为“完全模型”，把构造块体视为刚体，把地球近似为圆球，则块体在地表的运动可用该模型完全描述。其二称之为“平移模型”，当构造块体上的观测点不足时，通过增加约束条件，可用该模型描述块体间的相对运动。阐述了两种模型的适用范围以及确定运动参数的方法，导出了计算公式，并给出了两个算例。 相似文献
4.
变形分解作用是描述总的构造应变变形如何分解到一定意义分量的一个运动学概念。变形分解作用形成的构造应变变形分量之间的分解可以是表现在应变场的不均一性，也可以是同一应变场的，还可以是表现在构造力学性质、变形机制等的差异。因此，作为一种运动学概念，它涉及多个构造应用领域，研究者建立了多种不同的变形分解作用运动学模型并讨论其控制因素。为构造变形分解作用的研究提供了一种系统思维的研究思路，有利于更系统的认识相关地质构造之间存在的联系。综述了国内外学者对变形分解作用的研究。 相似文献
5.
李新 《中国科学:地球科学》2013,(11):1735-1742
不确定性是定量认识陆地表层系统的最大挑战之一．本文讨论了陆地表层系统中不确定性的来源及减小和控制不确定性的可能途径．从模型模拟的角度,不确定性的首要来源是影响陆地表层的参数、状态变量和近地表大气状态等边界条件的高度异质性．从观测的角度,我们首先用代表性误差的概念统一了由尺度代表性所引起的误差．代表性误差也主要来源于空间异质性,对于定点观测,它指将模型单元的模型状态映射到某一观测在其所代表性空间上的观测值时的误差,对于遥感观测,它是将地表变量映射到遥感原始观测的误差．从控制和减小系统不确定性的角度论证了模型和观测互补的重要性,提出应以随机的观点对待复杂的陆地表层系统;并通过对两种现代数据同化方法的介绍,说明数据同化是如何通过最大限度地融合模型和观测信息,来处理和控制不确定性,从而增强系统的可预报性和可观测性的．我们认为,新一代模型应描述动力学系统的统计分布,而观测应捕捉空间异质性,度量观测的代表性误差． 相似文献
6.
本文基于Ｂｕｒｒｉｄｇｅ，Ｋｎｏｐｏｆｆ（１９６７）的弹簧滑块模型和Ｂａｋ（１９８８）提出的细胞自动化模型，结合一些基本的物理概念和一些已知的观测结果，构造了用于观察一定区域内带断层的细胞自动化模型，得到了与实际地震活动类似的时空分布规律，验证并肯定了一些地震预报手段。 相似文献
7.
为研究地震子波相位对反射系数序列反演的影响,在自回归滑动平均(ARMA)模型描述子波的基础上,提出采用z域对称映射ARMA模型零极点的方法构造了一系列相同振幅谱、不同相位谱的地震子波,并结合谱除法对人工合成地震记录进行反射系数序列反演.理论分析表明,子波相位估计不准时反射系数序列反演结果中残留一个纯相位滤波器,该纯相位滤波器的相位谱为真实子波和构造子波的相位谱之差.采用丰度和变分作为评价方法,在反演结果中确定出真实的或准确的反射系数序列.仿真实验和实际数据处理结果也验证了子波相位对反射系数序列反演的影响规律和评价方法的有效性,为进一步提高反射系数序列反演结果精度指明了研究方向. 相似文献
8.
本文提出了地壳的构造运动，本质上是地壳与岩层的均衡差运动。它主要由重力作用产生的三种形式的差应力所推动：一是地球整体意义上的真正的重力均衡差应力；二是水平向的均衡差应力；三是垂直向的均衡差应力。本文讨论了这三种差应力产生的机制与规律，三种均衡差运动的规律与地壳实际构造运动普遍存在的对应关系，此外还讨论了地壳构造运动不息的主要原因。 相似文献
9.
吴忠良 《地震地磁观测与研究》1993,14(3):14-18
近年来地震统计力学研究的进展已经使我们有可能以一种简洁的方式将一些非线性地震模型物理地联系起来,并从地震学角度阐明这些模型的意义和限度。本文结合逾渗模型、热力学弹性回跳模型及弹簧滑块模型,系统地评述了这方面研究的进展。 相似文献
10.
《地震工程与工程振动》2020,(4)
针对目前预防预制空心板梁铰缝开裂的加固方法常存在施工复杂,造价较高的现象,提出了一种构造较为简单同时可为铰缝施工提供便捷的带锚固板连接钢筋的空心板铰缝构造。分别设计并制作了传统连接钢筋铰缝构造形式的空心板梁以及新型的带锚固板连接钢筋的铰缝构造形式的空心板梁模型。通过两者的静力试验,对比分析了两种模型的裂缝发展情况、钢筋应变、破坏形态和承载力等。试验结果表明:新型的带锚固板连接钢筋的铰缝构造形式可以延缓铰缝裂缝的出现,并且使空心板梁的极限承载力有所提高,从而改善铰缝的受力性能。 相似文献
11.
We present a systematic analysis of the dynamical behavior introduced by fault zone heterogeneities, using a simple mass-spring model with velocity-weakening friction. The model consists of two sliding blocks coupled to each other and to a constant velocity driver by clastic springs. The state of this system can be characterized by the positions of the two blocks relative to the driver. Symmetry stabilizes the system and generates only cyclic behavior. For an asymmetric system where the frictional forces for the two blocks are not equal, the solutions exhibit chaotic behavior. The transition from stable cyclic behavior to chaos is characterized by the period-doubling route to chaos. Lyapunov exponents are computed to quantify the deterministic chaos and to locate the onset of the chaotic evolution in parameter space. In many examples of deterministic chaos, chaotic behavior of a low-order system implies chaos in similar higher order systems. Thus, our results provide substantial evidence that crustal deformation is an example of deterministic chaos. 相似文献
12.
Irving J. Oppenheim 《地震工程与结构动力学》1992,21(11):1005-1017
The dynamic response of an unreinforced masonry arch is examined, modelling the rigid body motions of arch segments under the influence of gravitational and inertial forces. This extends earlier studies of single rocking blocks, stacked blocks, and portal mechanisms of blocks; the masonry arch is analysed as another kinematic form of such a system. In this first effort a part-circular planar arch ring is studied and excitation is restricted to horizontal ground acceleration of the base. The mechanism kinematics are presented and the governing equation of motion is derived in non-linear form. The instantaneous form is determined for small rotations about the initial geometry and is used to study the conditions for the onset of mechanism motion. Possible failure conditions are posed and bounding principles are stated. One possible failure condition, direct overturning as a four-link mechanism, is studied for one simplified base motion. The results show that an arch geometry establishes good resistance to earthquake excitation in that ground acceleration must exceed a rather high threshold before any mechanism motion would develop; however, once that threshold has been passed the arch has relatively modest resistance before failure. Other possible failure conditions are discussed; one emerges from pounding effects between segments at impact, and another develops from sliding of blocks over one another as the internal forces (normal and tangential to the masonry joint) vary with the inertial forces. 相似文献
13.
基于连续GPS数据,利用滑动块体模型研究了日本MW9.0地震前后沂沭断裂带两侧块体连续的相对运动状态,并研究其对区域地震活动的影响,结果表明日本地震以来：1）两侧块体呈右旋走滑兼挤压状态,平均走滑、挤压速率分别为0.9±0.1 mm·a-1和-0.7±0.1 mm·a-1,相比日本地震之前,运动过程更具起伏特征,可能与日本地震前后俯冲带两侧板块间相互运动状态的改变有关;2）沂沭断裂带两侧地区地震活动频次N、总释放能量折算震级M、地震活动度S值、地震b值与两侧块体相对运动的相关系数分别为0.66、0.69、0.74、-0.6,T检验显示相关性显著.在研究区地震能量集中释放阶段两侧块体相对运动方向和研究区主压应力方向一致,相对运动速率和地震活动强度变化具有同步特征,两侧块体相对运动对区域地震活动具有控制作用;3）莱州序列和乳山震群的发生可能与两侧块体相对运动促进的局部区域应力调整有关. 相似文献
14.
本文利用板块几何学的方法研究中国及邻区地块间的相对运动,用数值方法计算了地块运动的角速度及边界断层的滑动速率。计算结果与活断层数据相当吻合,本文还利用地块运动速度讨论了我国现代构造活动 相似文献
15.
16.
Ioannis N. Psycharis 《地震工程与结构动力学》1990,19(4):555-575
The dynamic behaviour of systems consisting of two blocks, one placed on the top of the other, and free to rock without sliding, is examined in this analysis. The equations of motion for each ‘mode’ of vibration are derived and criteria for the initiation of rocking and the transition between modes are given. During vibration, the system continuously changes from one mode to another and this makes the response non-linear. This transition may be accompanied by impact, in which case dissipation of energy occurs, the amount of which depends on the relative velocities and the dimensions of the blocks. Also, redistribution of the kinetic energy of the system in the blocks happens. In most cases, the fractional contribution from the upper block to the system energy increases, which results in a larger and longer response of the top block, compared to the vibration of the lower one. 相似文献
17.
青藏高原东北隅似三联点构造特征 总被引：27，自引：0，他引：27
在大陆内部,对于一定尺度的构造块体,似三联点构造是一种普通的构造形式。由于大陆内部块体旋转的普遍性,似三联点构造可形成顺旋型和逆旋型两种构造型式。 相似文献
18.
A numerical method of viscoelastic finite element coupled with spring-block model is developed to study temporal processes from the slow tectonic motion of large-scale crust to the rapid failure of small-scale faults. Our modeling demonstrates that the motion of crustal blocks is driven by forces from tectonic plate boundaries, and the deformation is distributed on faults for the stress accumulating. The coupling model generates earthquake sequences that display a magnitude-frequency scaling consistent with Gutenberg-Richter law. The frictional heterogeneities affect earthquakes occurrence and stresses distribution of crustal blocks. Rupture of earthquakes starts at the nucleation node, and propagates bilaterally along faults with the stress triggering, release and redistribution. The failure of faults releases part of crustal stresses, the stress state of crustal blocks near fault is affected by the rupture of local segments on the fault, and the stress state of crustal blocks far away from the fault is controlled by the seismic activity of the whole fault. 相似文献
19.
A numerical method of viscoelastic finite element coupled with spring-block model is developed to study temporal processes from the slow tectonic motion of large-scale crust to the rapid failure of small-scale faults. Our modeling demonstrates that the motion of crustal blocks is driven by forces from tectonic plate boundaries, and the deformation is distributed on faults for the stress accumulating. The coupling model generates earthquake sequences that display a magnitude-frequency scaling consistent with Gutenberg-Richter law. The frictional heterogeneities affeci earthquakes occurrence and stresses distribution of crustal blocks. Rupture of earthquakes starts at the nucleation node, and propagates bilaterally along faults with the stress triggering, release and redistribution. The failure of faults releases part of crustal stresses, the stress state of crustal blocks near fault is affected by the rupture of local segments on the fault, and the stress state of crustal blocks far away from the fault is controlled by the seismic activity of the whole fault. 相似文献
20.
R. S. JANGID 《地震工程与结构动力学》1996,25(11):1301-1306
Seismic response of a one-storey structure with sliding support to bidirectional (i.e. two horizontal components) earthquake ground motion is investigated. Frictional forces, which are mobilized at the sliding support, are assumed to have ideal Coulomb-friction characteristics. Coupling effects due to circular interaction between the frictional forces are incorporated in the governing equations of motion. Effects of bidirectional interaction of frictional forces on the response are investigated by comparing the response to two-component excitation with the corresponding response produced by the application of single-component excitations in each direction independently. It is observed that the response of the sliding structure is influenced significantly by the bidirectional interaction of frictional forces. Further, it is shown that the design sliding displacement may be underestimated if the bidirectional interaction of frictional forces is neglected and the sliding structures are designed merely on the basis of single-component excitation. 相似文献