Urbanization and eco-environment coupling circle theory and coupler regulation     

Fang  Chuanglin  Cui  Xuegang  Deng  Xiangzheng  Liang  Longwu 《地理学报(英文版)》2020,30(7):1043-1059

A near-distance, nonlinear coupling relationship objectively exists between urbanization and the eco-environment. The issue of how to coordinate the relationship between them has become a global strategic and scientific issue. This study reveals the nature, relationship and intensity of coupling between urbanization and the eco-environment from a theoretical perspective. Based on the strength of coupling, relationships can be characterized as having very-low, low, medium, high, very-high or full coupling intensity, which correspond to the categories of random coupling, indirect coupling, loose coupling, cooperative coupling, close coupling, and controlled coupling. Together, these make up an urbanization and eco-environment "coupling tower." This study also develops an urbanization and eco-environment coupling circle theory and generates 45 coupling graphs(including linear, exponential-curve, logarithmic-curve, double exponential-curve and S-curve graphs) per 10° of rotation of the coupling circle, with different graphs corresponding to different urban development stages and development models. Of the various coupling graphs, the S-curve graph is considered the optimum, as it reflects the best interactivity scenario between urbanization and the eco-environment. Using an S-curve coupling graph, and with the help of an SD model and based on the complex one-to-one, one-to-many, and many-to-many relationships between the variables, this study develops the Urbanization and Eco-environment Coupler(UEC). The UEC is composed of 11 regulating elements and 201 variables. If one variable changes, it changes the whole, affecting the structure, function and regulation of the entire coupler. The UEC includes three spatio-temporal scales: static regulation between multiple urbanization areas and eco-environment areas at the same time, dynamic regulation between the same urbanization area and eco-environment area at different times, and dynamic regulation between multiple urbanization areas and eco-environment areas at different times. Regulation gradually promotes evolution from low-level coupling to high-level coupling between urbanization and the eco-environment.  相似文献   

Spatio-temporal patterns of the interaction between groundwater and surface water in plains     

Cristian Guevara Ochoa  Agustín Medina Sierra  Luis Vives  Erik Zimmermann  Ryan Bailey 《水文研究》2020,34(6):1371-1392

The study of the dynamics of anthropic disturbances that have an effect on the hydrological systems in plains requires integral simulation tools for their diagnosis. The objective of this article is, first, to analyse and reproduce the spatio-temporal interactions between groundwater (GW) and surface water, net recharge, GW level, surface run-off, and evapotranspiration in the upper creek basin of Del Azul, which is located in the centre of the province of Buenos Aires, Argentina, and second, to obtain insights to apply the methodology to other similar situations. For this purpose, a model coupling the semidistributed hydrological model (Soil and Water Assessment Tool [SWAT]) and the hydrogeological model (MODFLOW) has been used. A simulation was carried out for a period of 13 years (2003–2015) on a daily scale. The application of the SWAT–MODFLOW coupling gave good results based on the adjustment between the calculated flows and levels, reaching a Nash–Sutcliffe of 0.6 and R²0.6 at the Seminario hydrometric station located at the watershed outlet point. According to the annual average balance, out of the total rainfall, evapotranspiration accounts for 85%, recharge accounts for 10.2%, and surface run-off accounts for 4.8%. Annual and monthly trends of the stream–aquifer interaction were determined, obtaining on average an annual GW discharge of 34 mm and an annual average recharge of the stream to the aquifer of 1.4 mm. Monthly GW discharges are higher in winter–spring (July to December with an average of 3.3 mm) and lower in summer–autumn (January to June with an average of 2.8 mm). The monthly average recharge of the stream towards the aquifer varies from 0.02 to 0.36 mm and is higher in March, May, and August, when water excess is produced in the basin. Through the analysis of coupled modelling, it is possible to analyse and reproduce the spatio-temporal transitions of flow existing between the stream, the hyporheic zone, and the aquifer.  相似文献   

Quantification of particle crushing in consideration of grading evolution of granular soils in biaxial shearing: A probability‐based model          下载免费PDF全文

Zhuang Cheng  Jianfeng Wang 《国际地质力学数值与分析法杂志》2018,42(3):488-515

A probability‐based model is presented to estimate particle crushing and the associated grading evolution in granular soils during isotropic compression and prepeak shearing in biaxial tests. The model is based on probability density functions of interparticle and intraparticle stress (ie, particle normalized maximum shear stress and particle average maximum shear stress) derived from discrete element method simulations of biaxial tests. We find that the probability density functions of normalized maximum shear stress are dependent on the current sample grading, implying coupling effects between particle crushing and sample grading such that the particle crushing is affected by the current sample grading, and the grading change is also dependent on the current particle crushing extent. To incorporate these coupling effects into the model, particle crushing and grading change are calculated for each load increment, in which the crushing probability of a particle during any loading increment is denoted as the corresponding increment of probability of the internal maximum shear stress exceeding its maximum shear strength. The model shows qualitative agreement with published experimental data. The effects of the model parameters, including initial porosity, particle strength, initial grading, and crushing mode, on the calculated results are discussed and compared with previous studies. Finally, the strengths and limitations of the model are discussed.  相似文献   

都江堰-汶川公路汶川地震次生地质灾害主要特征和形成机理   总被引：4，自引：3，他引：1  

甘建军  黄润秋  李前银  叶晓华  高文军 《地质力学学报》2010,16(2):146-158

汶川特大地震发生后, 都江堰至汶川公路两旁次生地质灾害尤为严重, 先后多次完全中断震中交通生命线, 严重地影响了公路的安全运行和灾后重建。通过对汶川地震前后都江堰-汶川公路边坡现场调查资料对比分析, 研究了该地段边坡的主要次生地质灾害类型及其破坏模式、形成机制和时空分布特点。破坏类型主要为碎屑流式、碎裂滑移式崩塌和碎裂-俯冲式、振荡-高速滑移式泥石流等, 造成沿线边坡发生大面积浅表生改造破坏。此类灾害具有丛集性、相关性、分段性的明显特点。成因复杂的高陡岩土体是次生地质灾害的主要物质基础;强烈的场地地震效应和内外动力耦合作用是该地区地质灾害成生的主要因素。   相似文献   

降雨入渗对路堤边坡稳定性研究   总被引：4，自引：2，他引：2  

刘俊新  刘育田  胡启军 《岩土力学》2010,31(3):903-910

基于非饱和土单变量的有效应力理论,建立了非饱和水-气两相的流体-固体耦合方程,在考虑地表径流-地下渗流和流体-固体双耦合的情况下,以达成线K240+10~70段因降雨产生的边坡破坏为工程实例,对计算理论模型进行了数值验证,同时对各种影响边坡稳定性因素进行了数值计算,对其破坏范围、降雨引起的破坏深度和入渗深度进行了分析,综合各种影响因素,其中降雨强度和历时及长期强度的影响最为明显。  相似文献   

热-水-应力耦合影响的有限元分析   总被引：4，自引：2，他引：2  

张玉军  张维庆 《岩土力学》2010,31(4):1269-1275

为了考虑应力拉压和压力（化学）溶解对裂隙开度的综合影响,对所建立的双重孔隙-裂隙介质热-水-应力耦合模型中裂隙开度的计算模型作了改进。通过一个假定的高放废物地质处置库算例,就岩体裂隙开度变化的3种工况,分析了岩体中的温度、孔（裂）隙水压力、地下水流速和主应力的变化、分布情况。结果显示：3种工况的计算域中温度场基本相同;孔（裂）隙水渗流场形态相似,但其量值有一定差别;工况1的裂隙开度在应力和压力（化学）溶解的共同作用下闭合量最大,负孔（裂）隙水压力增值最高;核废物的释热效应明显地改变了岩体自重应力场的水平分量,但对其垂直分量影响较小。  相似文献   

Coupling mechanisms in double sandbar systems. Part 1: patterns and physical explanation     

Bruno Castelle  B. G. Ruessink  Philippe Bonneton  Vincent Marieu  Nicolas Bruneau  Timothy D. Price 《地球表面变化过程与地形》2010,35(4):476-486

Crescentic sandbars and rip channels along wave‐dominated sandy beaches are relevant to understand localized beach and dune erosion during storms. In recent years, a paradigm shift from hydrodynamic template models to self‐organization mechanisms occurred to explain the formation of these rhythmic features. In double sandbar systems, both the inner‐ and outer‐bar rip channels and crescentic planshapes are now believed to be free instabilities of the nearshore system arising through self‐organization mechanisms alone. However, the occasional occurrence of one or two inner‐bar rip channels within one outer‐bar crescent suggests a forced, morphologically coupled origin. Here we use a nonlinear morphodynamic model to show that alongshore variability in outer‐bar depth, and the relative importance of wave breaking versus wave focussing by refraction across the outer bar, is crucial to the inner‐bar rip channel development. The coupling patterns simulated by our model are similar to those observed in the field. Morphological coupling requires a template in the morphology (outer‐bar geometry) which, through the positive feedback between flow, sediment transport and the evolving morphology (that is, self‐organization) enforces the development of coupling patterns. We therefore introduce a novel mechanism that blurs the distinction between self‐organization and template mechanisms. This mechanism may also be extended to explain the dynamics of other nearshore patterns, such as beach cusps. The impact of this novel mechanism on the alongshore variability of inner‐bar rip channels is investigated in the companion paper. Copyright © 2010 John Wiley and Sons, Ltd.  相似文献   

库水模型及库水深度对拱坝动力响应的影响     

陈江 《地震工程与工程振动》2010,30(2)

基于接触非线性有限元模型,以锦屏一级拱坝为例,库水分别采用附加质量模型、可压缩流体有限元模型、不可压缩流体有限元模型计算了正常蓄水位及运行低水位时坝体的动力响应,结果表明:库水模型对拱坝动力响应有较大影响,随库水深度的增大,各模型计算结果差异增大;相比于流体可压缩模型,采用不可压缩流体模型所得动力响应普遍偏大;运行低水位工况,由于静水压力减小导致拱效应减弱,从而降低了拱坝的整体性,因此运行低水位工况各缝开度普遍高于正常蓄水位工况,且其拉应力范围较大,因此,运行低水位工况将对抗震设计起控制作用。  相似文献   

区域尺度土壤固碳量估算方法评述   总被引：7，自引：1，他引：6  

常瑞英  刘国华  傅伯杰 《地理研究》2010,29(9):1616-1628

增加陆地生态系统碳汇已成为一项重要的减排手段,被纳入有关国际气候变化协定。区域尺度土壤固碳量估算成为当前研究的热点与难点。本文综述了目前国内外常用的区域土壤固碳量估算方法,并依据估算精度与方法差异将这些方法总结为四类:简易模型、清查法、经验模型和基于GIS的机理模型。同时对这四类方法的特点和适用性进行了评述,建议根据研究地区及目的不同选择合适的方法。此后,通过分析土壤固碳机理、数据收集、尺度推移、情景分析和土壤有机质机理模型发展等与区域土壤固碳量估算密切相关的各方面中存在的不足,提出今后区域尺度土壤固碳量估算方法将向耦合土壤有机质机理模型、土壤可溶性碳模型、土地利用模型和区域水文模型的基于GIS平台的区域综合模型方向发展。  相似文献   

台资跨境生产网络的空间重组——电脑企业从珠三角到长三角的转移   总被引：6，自引：1，他引：5  

杨春 《地理学报》2011,66(10):1343-1354

基于从全球生产网络(GPNs) 层面分析区域发展战略性耦合(strategic coupling)的视角,本文探讨自21 世纪初以来,台资跨境生产网络在中国大陆的空间重组,特别是个人电脑 (计算机) 企业从珠三角向长三角地区再布局的动力机制与格局。通过对相关企业的深度访谈与个案研究,指出台资个人电脑企业在珠三角地区与长三角地区的空间再布局是在各区域地方制度下,GPNs 架构中全球领先企业(global lead firms) 与分布在2 个三角洲区域处于 GPNs 较低层级供应企业(supplier firms) 之间进行不同的战略性耦合之结果。研究阐明在经济全球化背景下‘新区域主义’理论对区域发展仅分析区域内部因素之局限性,因应跨地域 (trans-local) 动力的出现,全球生产网络视角下区域内部与外部因素的战略耦合,已成为理解全球经济化下区域发展的重要理论框架。  相似文献