Hysteresis‐based flood‐wave analysis using the concept of strain     

Surendra Kumar Mishra  Vijay P. Singh 《水文研究》2001,15(9):1635-1651

Hysteresis represents a loop in a rating curve and is a phenomenon which closely resembles that occurring in stress–strain curves used for studying the elastic properties of solid substances in engineering mechanics. Earlier hysteresis‐based studies used for defining floodwave propagation in open channels have qualitatively shown that hysteresis is an index of energy loss during floodwave propagation. Using the concept of elasticity, this paper introduces a new term called flow strain (defined as the ratio of change in discharge to the initial discharge) for investigating hysteresis. The usefulness of this new term is evaluated with use of four dam‐break studies. The study reveals that:

• 1 flow strain is a function of three wave speeds, Seddon speed, Lagrange speed, and elastic speed;
• 2 a single linear reservoir concept frequently used in flood routing is a specific variant of the Seddon speed formula;
• 3 the non‐linear storage–discharge relationship, widely used in overland flow modelling, is a variant of the kinematic wave representation;
• 4 the discharge ordinates on the recession part of a hydrograph follow a simple first‐order autoregressive form;
• 5 the hysteresis, phase difference and logarithmic decrement all define attenuation and are indices of energy loss during floodwave propagation.

Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

亚洲中东部岩石圈下层网络状塑性流动与应变场   总被引：6，自引：0，他引：6  

王绳祖 《地质论评》2001,47(5):459-466

在板块边缘驱动力的挤压作用下,岩石圈下层（含下地壳和岩石圈地幔）塑性流动网络的共轭角随着变形的增大而由初始的直角变为钝角,因此,可根据共轭角的增量推测应变的大小,并给出该层的应变场,亚洲中东部所含3个塑性流动网络系统的研究表明,岩石圈下层的应变场控制或影响着上部地壳的构造变形和地形起伏,表现在应变“凸锋~”与地形凸峰之间的相互对应以及“稳定”块体的低应变效应和应变的波动传播,网络共轭角推测应变的方法为认识板内应变场和构造变形提供了新的途径。  相似文献   

等幅侧向位移循环下柱混凝土纤维应变规律的试验研究     

傅剑平  李英民  王敏  陈小英  白绍良 《地震工程与工程振动》2005,25(6):88-95

在已完成的包括16个构件的等位移循环加载钢筋混凝土柱的系列试验中，通过在其中3根柱的塑性铰区沿混凝土受力方向安设位移计，较准确测定了混凝土测试标距内的平均应变在一个加载循环内的变化规律及其随周数增长的变化规律；发现了单周最大压应变随周数的增长而持续增大，单周最大名义拉应变随周数增长而持续减小的重要现象；并与柱顶水平力-水平位移滞回规律实测结果相对应，结合截面受力特征对所得单周和多周应变变化规律的成因作了分析。  相似文献   

昆仑山口西8.1级地震地表破裂参数相互关系的新认识          下载免费PDF全文

田勤俭  张立人  郝平  王赞军  王志才 《地震地质》2005,27(1):20-30

地震地表破裂带调查表明,昆仑山口西 8. 1级地震的破裂长度为 426km,最大水平位移6m左右,地震破裂位移的分布明显地受断层活动段控制。该次地震的破裂长度远大于统计值,文中应用地壳极限线应变的概念,通过比较中国大陆内部几次走滑型强震的地震破裂最大位移与破裂长度的关系,论述了昆仑山口西 8. 1级地震中各次级段破裂的相对独立特征,认为该次强震不是一次整体性破裂事件,而是由连续触发的几次地震组成  相似文献   

A structural model for the seismicity of the Arudy (1980) epicentral area (Western Pyrenees, France)     

Noalwenn Dubos-Sallée  Bertrand Nivière  Pierre Lacan  Yves Hervouët 《Geophysical Journal International》2007,171(1):259-270

The Western Pyrenees presents a diffuse and moderate ( M ≤ 5.7) instrumental seismicity. It nevertheless historically suffered from strong earthquakes (I = IX MSK). The seismic sources of these events are not yet clearly identified. We focus on the Arudy (1980) epicentral area ( M = 5.1) and propose here the reactivation of early Cretaceous normal faults of the Iberian margin as a potential source. The late Cretaceous inversion of this basin, first in a left-lateral strike-slip mode and then in a more frontal convergence, resulted in a pop-up geometry. This flower structure attests of the presence of a deep crustal discontinuity.
The present-day geodynamic arrangement suggests that this accident is reactivated in a right lateral mode. This reactivation leads to a strain partitioning between the deep discontinuity that accommodates the lateral component of the motion and shallow thrusts, rooted on this discontinuity. These thrusts accommodate the shortening component of the strain. The distribution of the instrumental seismicity fits well the structural model of the Arudy basin. Whatever the compressive regional context, the structural behaviour of the system explains too the extensive stress tensor determined for the Arudy crisis if we interpret it in terms of strain ellipsoid. Indeed numerical modelling has shown that this concomitant activity of strike-slip and thrust faulting results in an extensive component that can rise 50 per cent of the finite strain.
We identify too a 25–30 km long potential seismic source for the Arudy area. The size of the structure and its potential reactivation in a strike-slip mode suggest that a maximum earthquake magnitude of ∼6.5 could be expected. The extrapolation of this model at the scale of the Western Pyrenees allows to propose other potential sources for major regional historical earthquakes.  相似文献   

Fault induced permanent ground deformations: Experimental verification of wet and dry soil, numerical findings’ relation to field observations of tunnel damage and implications for design     

Jrgen Johansson  Kazuo Konagai 《Soil Dynamics and Earthquake Engineering》2007,27(10):938-956

Few building codes contains provisions fault surface ruptures and accompanying soil deformations which constitutes a great risk to human lives, buildings and infrastructure. A numerical and experimental comparison show a fair agreement of result. Analysis of “real” scale show the how water increases the incompressibility of wet soil causing shear deformations to become larger and conjugate ruptures to appear for reverse faults. Field observations and numerical analysis indicates that horizontal compression of soil surrounding underground structures should be taken into account in design.  相似文献   

Influence of the Kunlun Mountain Ms8.1 Earthquake on Horizontal Crustal Deformation in the Sichuan and Yunnan Area     

Yang Guohua 《中国地震研究》2007,21(3):269-280

In order to track the space-time variation of regional strain field holistically(in a large scale) and to describe the regional movement field more objectively,the paper uses a nonlinear continuous strain model focused on extracting medium-low frequency strain information on the basis of a region with no rotation.According to the repeated measurements(1999～2001～2004) from GPS monitoring stations in the Sichuan and Yunnan area obtained by the Project of "China Crust Movement Measuring Network",and with the movement of 1999～2001(stage deformation background) as the basic reference,we separated the main influencing factors of the Kunlun Mountain M-S8.1 earthquake in 2001 from the data of 2001 and 2004,and the results indicate:(1) the Kunlun Mountain M-S8.1 earthquake has a discriminating effect on the Sichuan and Yunnan area,moreover,the deformation mode and background had not only certain similitude but also some diversity;(2) The movement field before the earthquake was very ordinal,while after the earthquake,order and disorder existed simultaneously in the displacement field;The displacement quantities of GPS monitoring stations were generally several millimeters;(3) The principal strain field before earthquake was basically tensile in an approximate EW direction and compressive in the SN direction,and tension was predominant.After the earthquake,the principal strain field in the Sichuan area was compressive in the EW direction and tensile in the SN direction,and the compression was predominant.In the Yunnan area,it was tensional in the NE direction and compressive in the NW direction,and tension was predominant;(4) The surficial strain before the earthquake was dominated by superficial expansion,the contractive area being located basically in the east boundary of Sichuan and Yunnan block and its neighborhood.After the earthquake,the Sichuan area was surface contractive(the further north,the greater it was),and south of it was an area of superficial expansion.Generally speaking,the Kunlun Mountain M-S8.1 earthquake played an active role in the accumulation of energy in the Sichuan and Yunnan area.Special attention shall be focused on the segment of Xichang-Dongchuan and its neighborhood.  相似文献   

Corresponding Relation Between the Space-time Evolution of Seismic Apparent Strain and the Region of Strong Earthquakes in Yunnan     

Zhang Bin 《中国地震研究》2007,21(3):293-303

On the basis of our predecessors' research,we study the distribution and the space-time evolution characteristics of the seismic apparent strain field in Yunnan since the 1970's using the seismic data of Yunnan and its surrounding areas.The result shows that there is a rather strong corresponding relationship between the anomaly region of seismic apparent strain and strong earthquakes.In the nine earthquakes studied,anomaly areas of seismic apparent strain had appeared before eight earthquakes,including five occurring in the anomaly region and three on the edge.Finally,the investigative result is demonstrated primarily.  相似文献   

松潘-平武地震前地震视应变场的时空演变          下载免费PDF全文

张彬  杨选辉  易志刚 《地震工程学报》2007,29(3):235-239

利用松潘-平武周边地区的地震资料研究了1970-1975年该地区地震视应变场的分布和时空变化特征。结果表明,地震视应变的时空变化与松潘-平武强震具有很好的对应关系,1970年在附近就出现异常区,并且地震视应变总体上逐年增加,地震就发生在地震视应变异常区。  相似文献   

由井-含水层系统的水位动态反演含水层体应变     

晏锐  高福旺  陈颙 《中国地震》2007,23(3):303-309

以孔隙弹性理论和水文地质学原理为基础,给出井水位波动与含水层介质体应变变化关系的数学表达式,结合固体潮理论分析了井—含水层系统水位潮汐波动对体应变固体潮的响应特征,用水位潮汐波来反演含水层体应变的变化,将反演结果与体应变实测资料得到的结果进行对比,发现二者有较好的一致性,说明用水位潮汐波来反演含水层体应变的方法是可行的,它为了解含水层的水文地质特性、体应变的变化及探索地震前兆提供了借鉴。  相似文献