考虑循环软化的非线性动力本构模型在FLAC3D中的实现     

徐令宇  蔡飞  陈国兴  王国新 《岩土力学》2016,37(11):3329-3335

已有震害研究表明,震后边坡会因持续变形而破坏,且伴随着土体强度逐渐降低的现象,即土的循环软化行为。因此,有必要研究考虑循环软化的非线性动力本构模型以用于复杂条件下地震边坡稳定性分析。在已有的非线性动力本构模型基础上,提出了考虑循环软化的处理方法。同时,在FLAC3D平台上实现了本构模型二次开发,并通过了理论公式与已有文献中试验数据的验证。结果表明：计算出的骨干曲线与理论公式一致,且计算出的动剪切模量比及阻尼比与试验数据吻合较好,能够克服Hardin-Drnevich模型和Davidenkov模型在较大应变处（>0.01%）过高地估算阻尼比的缺陷;考虑了循环软化后,计算出的剪切强度有明显降低,且当遇到骨干曲线剪应力可以连续地过渡到软化后的主干曲线上,模型的收敛性较好。所开发的本构模型可为大应变条件下软土场地及边坡地震灾害评估提供支持。  相似文献   

斜坡降雨入渗在Flac中模拟   总被引：1，自引：0，他引：1  

刘俊新  刘育田  甘建军 《四川地质学报》2009,29(3):316-319

为了简化分析,在模拟斜坡降雨入渗暂态渗流时,通常没有考虑入渗和产流的耦合过程,通过施加流量边界或零水头边界进行地下水渗流计算,通过在FALC中利用内嵌的fish语言,考虑地表径流和地下渗流的耦合以及雨向影响下斜坡降雨入渗过程,并通过算例分析了考虑和不考虑耦合、对斜坡孔隙水压力分布以及考虑各种雨向作用下对坡面积水深度的影响。  相似文献   

稠油成因研究综述   总被引：5，自引：0，他引：5  

胡守志  张冬梅  唐静  顾军 《地质科技情报》2009,28(2)

在阐述稠油地球化学特征基础上,对稠油的成因及其判识的最新研究进展进行了综述,稠油成因类型分原生型和次生型,其中,次生型稠油主要由生物降解、水洗和氧化作用分解、消耗或氧化原油中的烃类组分,使非烃和沥青质含量相对增加,致使原油密度和黏度增大,油质变稠.最后指出了目前稠油成因机制研究中存在的问题以及今后发展的方向.  相似文献   

Norwegian school geography and geographical education: A new research field?     

Elisabeth Eikli 《Norsk geografisk tidsskrift. Norwegian journal of geography》2013,67(3):128-134

Despite having a long-standing relationship, teacher education and geography in primary and secondary education in Norway has received little attention as a research field within academic geography until recently. The author asks: How has Norwegian school geography related to geography taught at universities? Where does research on school geography and geographical education stand today and where should it go from here? She examines the development of the role played by academic geographers in the field from the 1970s until the present. Some potential future venues for this emerging research field are suggested on the basis of an examination of what themes are current focal points for research and comparing them to what other countries consider essential in their teacher education.  相似文献   

Modeling the Permeability Loss of Metallic Iron Water Filtration Systems     

Sabine Caré  Richard Crane  Paolo S. Calabrò  Antoine Ghauch  Emile Temgoua  Chicgoua Noubactep 《洁净——土壤、空气、水》2013,41(3):275-282

Over the past 30 years the literature has burgeoned with in situ approaches for groundwater remediation. Of the methods currently available, the use of metallic iron (Fe⁰) in permeable reactive barrier (PRB) systems is one of the most commonly applied. Despite such interest, an increasing amount of experimental and field observations have reported inconsistent Fe⁰ barrier operation compared to contemporary theory. In the current work, a critical review of the physical chemistry of aqueous Fe⁰ corrosion in porous media is presented. Subsequent implications for the design of Fe⁰ filtration systems are modeled. The results suggest that: (i) for the pH range of natural waters (>4.5), the high volumetric expansion of Fe⁰ during oxidation and precipitation dictates that Fe⁰ should be mixed with a non‐expansive material; (ii) naturally occurring solute precipitates have a negligible impact on permeability loss compared to Fe⁰ expansive corrosion; and (iii) the proliferation of H₂ metabolizing bacteria may contribute to alleviate permeability loss. As a consequence, it is suggested that more emphasis must be placed on future work with regard to considering the Fe⁰ PRB system as a physical (size‐exclusion) water filter device.  相似文献   

Metallic Iron for Water Treatment: A Critical Review     

Chicgoua Noubactep 《洁净——土壤、空气、水》2013,41(7):702-710

Water treatment with metallic iron (Fe⁰) is still based on the premise that Fe⁰ is a reducing agent. An alternative concept stipulates that contaminants are removed by adsorption, co‐precipitation, and size‐exclusion in a reactive filtration process. This article underlines the universal validity of the alternative concept. It is shown that admixing non‐expansive material to Fe⁰ as a pre‐requisite for sustainable Fe⁰‐based filtration systems. Fe⁰‐based filters are demonstrated an affordable, appropriate, and efficient decentralized water treatment technology.  相似文献   

基于ArcEngine的次生火灾蔓延模拟及评估系统     

苏顺谦  吴良才 《测绘与空间地理信息》2013,36(6):135-137,141

次生火灾对人类的危害极大。分析次生火灾的产生原因,研究次生火灾的起火点预测模型、火灾蔓延影响因素和蔓延模型、影响评估模型。基于ArcEngine组件开发了次生火灾蔓延模拟及评估系统分析评估系统。该系统可以模拟单个或多个起火点的动态蔓延和分析评估次生火灾对人类生命财产造成的损失。  相似文献   

基于AutoCAD平台的数字化清绘系统开发     

陈广扬 《测绘与空间地理信息》2013,(10):238-240,244

针对目前航测外业数字化清绘的需求提出了一个基于AutoCAD平台的航测外业数字化清绘系统,并通过对该系统的需求分析、系统设计、系统功能等方面进行了较为详细的论述,并实现了系统的主要功能。  相似文献   

An Algorithm for Localised Contour Removal over Steep Terrain     

《The Cartographic journal》2013,50(2):144-156

Abstract

Isolines have proved to be a highly effective way of conveying the shape of a surface (most commonly in the form of height contours to convey geographical landscape). Selecting the right contour interval is a compromise between showing sufficient detail in flat regions, whilst avoiding excessive crowding of lines in steep and morphologically complex areas. The traditional way of avoiding coalescence and confusion across steep regions has been to manually remove short sections of intermediate contours, while retaining index contours. Incorporating humans in automated environments is not viable. This research reports on the design, implementation and evaluation of an automated solution to this problem involving the automatic identification of coalescing lines, and removal of line segments to ensure clarity in the interpretation of contour information. Evaluation was made by subjective comparison with Ordnance Survey products. The results were found to be very close to the quality associated with manual techniques.  相似文献   

临清坳陷东部石炭-二叠系二次生烃差异性研究   总被引：2，自引：0，他引：2  

陈武珍  陈红汉  李文涛  丰勇  宫雪  熊万林 《沉积学报》2012,30(1):179-188

受盆地多旋回叠加和反转演化控制,临清坳陷东部石炭-二叠系含煤系地层烃源岩经历了二次生烃过程,并在空间上表现出强烈的差异性。通过对这套烃源岩生烃史模拟结果表明,石炭-二叠系烃源岩于早中三叠世进入生烃门限,随后印支运动造成全区生烃中止,中新生代烃源岩再次深埋,发生二次生烃作用。不同井区二次生烃在时间和空间上存在差异性,洼陷带发育三个“二次生烃”阶段,生烃高峰期发生在新生代,凸起带发育两个“二次生烃”阶段,生烃高峰期发生在中生代,隆起区尚未发生二次生烃。二次生烃早期生成的烃类基本遭受破坏,晚期生成的烃类具备成藏条件,是勘探的主要目标。现今洼陷带烃源岩已进入成熟-高成熟阶段,成为晚期煤成气藏的气灶。  相似文献