计算分层介质中位错点源静态位移场的广义反射、透射系数矩阵和离散波数方法          下载免费PDF全文

谢小碧  姚振兴 《地球物理学报》1989,32(3):270-280

本文将计算合成地震图的广义反射、透射系数矩阵和离散波数方法应用于静态问题,给出了分层介质中位错点源产生的静态位移场的计算方法。该方法保留了反射、透射矩阵方法的原有优点,通过将数值结果与解析解的对比表明,该方法具有较高的数值精度,可用于研究地震断层活动造成的地表形变。  相似文献   

Fault dimensions,displacements and growth   总被引：15，自引：0，他引：15  

Juan Watterson 《Pure and Applied Geophysics》1986,124(1-2):365-373

Maximum total displacement (D) is plotted against fault or thrust width(W) for 65 faults, thrusts, and groups of faults from a variety of geological environments. Displacements range from 0.4 m to 40 km and widths from 150 m to 630 km, and there is a near linear relationship betweenD andW ². The required compatibility strains (e _s) in rocks adjacent to these faults increases linearly withW and with and ranges frome _s=2×10^–4 toe _s=3×10^–1. These are permanent ductile strains, which compare with values ofe _s=2×10^–5 for the elastic strains imposed during single slip earthquake events, which are characterised by a linear relationship between slip (u) andW.The data are consisten with a simple growth model for faults and thrusts, in which the slip in successive events increases by increments of constant size, and which predicts a relationship between displacement and width of the formD=cW ². Incorporation of constant ductile strain rate into the model shows that the repreat time for slip events remains constant throughout the life of a fault, while the displacement rate increases with time. An internally consistent model withe _s=2×10^–5, giving repeat times of 160 years and instantaneous displacement rates of 0.02 cm/yr, 0.2 cm/yr, and 2.0 cm/yr when total displacement is 1 m, 100 m, and 10 km, and slip increasing by 0.5 mm with each event, gives a good approximation of the data. The model is also applicable to stable sliding, the slip rate varying with ductile strain rate and withW ².  相似文献   

位移时空综合分析法及其在深基坑中的应用   总被引：2，自引：4，他引：2  

杨志法  张红梅 《工程地质学报》1995,3(4):32-38

对于岩土工程设计和施工来说,如何对监测所获的位移信息进行分析十分重要。以往主要采用位移-时间的分析方法。但为了使信息在修改设计和指导施工方面起更大作用,本文提出位移空间比较分析法,并主张与常用的位移-时间分析方法结合使用,以形成所谓位移时空综合分析法。在济南彩云大厦深基坑等的成功应用,表明该法是可行的。  相似文献   

粘滑失稳及其物理场时空分布的实验研究   总被引：6，自引：3，他引：6  

邓志辉  马胜利 《地震地质》1995,17(4):305-310

摩擦滑动的物理场实验研究表明：（１）能量空间分布的差异是失稳的重要条件，单发型大事件常发生于高能量向低能量的突变带或高能量背景区内的相对低能量区；（２）单发型大事件的孕育过程常常经历若干个能量输入输出循环，产生多个前兆阶段，并在失稳前源区常有一个弱化过程。小震或群发型事件失稳前常常只有一个能量积累与强化的过程，失稳前兆阶段性反映较差；（３）粘滑失稳时断层的位错与声发射的大小未见明显关系  相似文献   

考虑高振型影响的结构层间位移能力谱分析方法   总被引：5，自引：0，他引：5  

王克峰  周云 《地震工程与工程振动》2005,25(3):33-40

工程界普遍采用的能力谱分析方法是建立在结构单自由度简化假设基础上，利用结构基本振型来进行能力分析。虽然此简化假设可以为工程界提供一种简便的分析方法，但从其分析效果来看，简化方法并不能很好地反映结构真实地震反应。高振型对结构局部变形的影响在分析结构动力反应特性中是很重要的因素，不应忽略掉。基于上述对现有能力谱分析方法不足之处的考虑，从提高结构能力谱分析方法的准确性出发，本文在Chopra能力谱分析方法的基础之上，根据我国振型分解反应谱思想，在能力谱分析方法中引入了结构高振型的影响分析，并提出了考虑结构高振型影响的结构层间位移能力谱分析方法的一般步骤。通过平面框架结构体系的算例分析，说明上述推荐方法在改进能力谱分析精度上的有效性。  相似文献   

双节点有限元模拟直立走滑断裂地震位移场   总被引：2，自引：0，他引：2  

朱桂芝  王庆良 《地震研究》2005,28(2):189-192

结合位错理论和有限单元法，对介质横向不均匀性引起的直立走滑断裂地震水平位移场不对称性进行了数值模拟研究。结果表明，断层两侧介质泊松比和弹性模量的横向不均匀性，均可以引起直立走滑断层同震破裂及地震位移场的不对称性，其中，断层两侧介质的剪切模量比(刚度比)对直立走滑断裂地震位移场不对称性起主要作用。  相似文献   

Rainfall intensity characteristics at coastal and high altitude stations in Kerala   总被引：1，自引：0，他引：1  

V. Sasi Kumar  S. Sampath  P. V. S. S. K. Vinayak  R. Harikumar 《Journal of Earth System Science》2007,116(5):451-463

Rainfall intensities measured at a few stations in Kerala during 2001–2005 using a disdrometer were found to be in reasonable agreement with the total rainfall measured using a manual rain gauge. The temporal distributions of rainfall intensity at different places and during different months show that rainfall is of low intensity (< 10 mm/hr), 65% to 90% of the time. This could be an indication of the relative prevalence of stratiform and cumuliform clouds. Rainfall was of intensity < 5 mm/hr for more than 95% of the time in Kochi in July 2002, which was a month seriously deficient in rainfall, indicating that the deficiency was probably due to the relative absence of cumuliform clouds. Cumulative distribution graphs are also plotted and fitted with the Weibull distribution. The fit parameters do not appear to have any consistent pattern. The higher intensities also contributed significantly to total rainfall most of the time, except in Munnar (a hill station). In this analysis also, the rainfall in Kochi in July 2002 was found to have less presence of high intensities. This supports the hypothesis that the rainfall deficiency was probably caused by the absence of conditions that favoured the formation of cumuliform clouds.  相似文献   

Some Insights into Topographic,Elastic and Self-gravitation Interaction in Modelling Ground Deformation and Gravity Changes in Active Volcanic Areas     

María Charco  José Fernández  Francisco Luzón  Kristy F. Tiampo  John B. Rundle 《Pure and Applied Geophysics》2007,164(4):865-878

Surface displacements and gravity changes due to volcanic sources are influenced by medium properties. We investigate topographic, elastic and self-gravitation interaction in order to outline the major factors that are significant in data modelling. While elastic-gravitational models can provide a suitable approximation to problems of volcanic loading in areas where topographic relief is negligible, for prominent volcanoes the rough topography could affect deformation and gravity changes to a greater extent than self-gravitation. This fact requires the selection, depending on local relief, of a suitable model for use in the interpretation of surface precursors of volcanic activity. We use the three-dimensional Indirect Boundary Element Method to examine the effects of topography on deformation and gravity changes in models of magma chamber inflation/deflation. Topography has a significant effect on predicted surface deformation and gravity changes. Both the magnitude and pattern of the geodetic signals are significantly different compared to half-space solutions. Thus, failure to account for topographic effects in areas of prominent relief can bias the estimate of volcanic source parameters, since the magnitude and pattern of deformation and gravity changes depend on such effects.  相似文献   

A comparison of single‐run pushover analysis techniques for seismic assessment of bridges     

R. Pinho  C. Casarotti  S. Antoniou 《地震工程与结构动力学》2007,36(10):1347-1362

Traditional pushover analysis is performed subjecting the structure to monotonically increasing lateral forces with invariant distribution until a target displacement is reached; both the force distribution and target displacement are hence based on the assumption that the response is controlled by a fundamental mode, that remains unchanged throughout. However, such invariant force distributions cannot account for the redistribution of inertia forces caused by structural yielding and the associated changes in the vibration properties, including the increase of higher‐mode participation. In order to overcome such drawbacks, but still keep the simplicity of using single‐run pushover analysis, as opposed to multiple‐analyses schemes, adaptive pushover techniques have recently been proposed. In order to investigate the effectiveness of such new pushover schemes in assessing bridges subjected to seismic action, so far object of only limited scrutiny, an analytical parametric study, conducted on a suite of continuous multi‐span bridges, is carried out. The study seems to show that, with respect to conventional pushover methods, these novel single‐run approaches can lead to the attainment of improved predictions. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Effectiveness of simple approaches in mitigating residual deformations in buildings     

Didier Pettinga  Constantin Christopoulos  Stefano Pampanin  Nigel Priestley 《地震工程与结构动力学》2007,36(12):1763-1783

Developments in performance‐based seismic design and assessment approaches have emphasized the importance of considering residual deformations. Recent investigations have also led to a proposed direct displacement‐based design (DDBD) approach which includes an explicit consideration of the expected residual deformations as an integral part of the design process. Having estimated the expected residual deformations in a structure, engineers are faced with the problem of reducing them to meet the targeted performance levels under pre‐defined seismic hazard levels. Previous studies have identified the post‐yield stiffness as a primary factor influencing the magnitude of residual deformations in single degree of freedom and multiple degree of freedom structures. In this paper, a series of simple approaches to increase the post‐yield stiffness of traditional framed and braced systems for the purpose of reducing residual deformations are investigated. These methods do not utilize recentring post‐tensioned technology. This contribution addresses the feasibility of altering the lateral post‐yield stiffness of structural systems by: (i) using different reinforcement materials with beneficial features in their stress–strain behaviour; (ii) re‐designing the section geometry and properties of primary seismic‐resisting elements; and (iii) introducing a secondary elastic frame to act in parallel with the primary system. The efficiency of each of these techniques is investigated through monotonic and cyclic moment‐curvature and non‐linear time‐history analyses. Of these approaches the design and introduction of an elastic secondary system was found to be most effective and consistent in reducing residual deformations. A simplified design approach for achieving the desired increase of a system's post‐yield stiffness is also presented. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献