地震载荷下斜坡稳定性数值模拟分析     

王来贵  王燕德  刘贺  李磊 《中国地质灾害与防治学报》2011,22(4):18-23

地震载荷是影响复杂结构斜坡塌滑的一个重要因素。本文以汶川震区一边坡为实例,利用有限差分法FLAC-3D对地震动力下斜坡进行了数值模拟。并且在用FLAC-3D进行斜坡动力分析时探讨了边界条件设置、动力时程的合成以及输入和转化。从位移场与速度场进行了详细的动力分析,获得该斜坡地震载荷下位移场、速度场的变化规律,指出山体斜坡在非连续介质状态下软弱面区域位移和速度最大,为后续进行复杂的山体破坏力学研究提供理论依据。  相似文献   

一种提高泥石流防撞墩抗冲击性能的方法     

罗祥  石少卿  严庆平 《地质灾害与环境保护》2011,22(3):89-93

为提高桥墩泥石流防撞墩的抗冲击性能,拟将废旧轮胎堆栈于防撞墩前,与之形成一种刚柔复合结构.并使用显式动力有限元软件LS-DYNA,通过对泥石流大石块的冲击过程进行数值计算,发现当冲击能量在轮胎的吸能范围时,其冲击力能降低80％.  相似文献   

晚三叠世龙门山前陆盆地早期(卡尼期)碳酸盐缓坡和海绵礁的淹没过程与动力机制   总被引：2，自引：2，他引：0  

李勇  苏德辰  董顺利  孙玮  杨荣军  刘树根  颜照坤  闫亮 《岩石学报》2011,27(11):3460-3470

晚三叠世龙门山前陆盆地分布于扬子克拉通西缘,属于印支期造山楔构造负载驱动的挠曲型前渊凹陷.其中卡尼期马鞍塘组是分布于底部不整合面之上的第一套地层单元,记录了前缘隆起边缘碳酸盐缓坡和海绵礁的构建和淹没过程.据钻孔揭示马鞍塘组的最大厚度超过250m,显示为西北厚东南薄的楔形结构,从北西向南东依次分布了深水盆地、碳酸盐缓坡和海绵礁和浅水滨岸带等沉积物类型.其中碳酸盐缓坡和海绵礁分布于前陆盆地的远端,呈面向西的条带状展布,其走向线与龙门山冲断带的走向大致平行.碳酸盐缓坡和海绵礁的厚度介于30～100m之间,由北西向南东变薄.在垂向上,马鞍塘组由3部分构成,下部为鲕粒滩和生物碎屑滩,中部为海绵礁,上部为黑色页岩,显示为向上变细、变深的沉积序列.在Li et al.(2003)盆地模拟的基础上,本次对卡尼期前陆盆地的沉降速率、沉积速率、海绵礁生长速率、相对海平面上升速率进行了定量计算,其中沉降速率为0.10mm·a-1、沉积速率为0.04mm·a-1、海绵礁生长速率为0.03mm·a-1、相对海平面上升速率介于0.01mm·a-1～0.05mm · a-1之间.研究结果表明:在卡尼期早期,相对海平面处于初始上升阶段,相对海平面上升速率较小,盆地处于欠补偿状态,沉积了碳酸盐缓坡型鲕粒滩和生物碎屑滩;在卡尼期中期,相对海平面上升速率等于海绵礁生长速率,海绵礁持续保持垂直向上的生长状态,形成了高度达100余米的塔礁;在卡尼期晚期,相对海平面上升速率大于海绵礁生长速率,礁顶的水深逐步变大,导致礁体被淹溺致死,从而在卡尼期形成了鲕粒灰岩滩-生物碎屑滩-海绵礁灰岩-页岩的向上变细、变深的沉积序列,显示了前陆盆地早期碳酸盐缓坡和海绵礁生长并被淹没的特有模式.本次研究成果表明龙门山前陆盆地的底部不整合面和碳酸盐缓坡、海绵礁的淹没过程是扬子板块西缘印支期造山楔逆冲构造负载的挠曲变形的产物,显示了在卡尼期松潘-甘孜残留洋盆的迅速闭合和造山楔构造负载向扬子板块的推进过程.  相似文献   

Analysis of permanent deformations of railway embankments under repeated vehicle loadings in permafrost regions     

Wei M  Tuo Chen 《寒旱区科学》2015,7(6):645-653

By large-scale dynamic tests carried out on a traditional sand-gravel embankment at the Beilu River section along the Qinghai-Tibet Railroad, we collected the acceleration waveforms close to the railway tracks when trains passed. The dynamic train loading was converted into an equivalent creep stress, using an equivalent static force method. Also, the creep equation of frozen soil was introduced according to the results of frozen soil rheological triaxial tests. A coupled creep model based on a time-hardening power function rule and the Druker-Prager yield and failure criterion was established to analyze the creep effects of a plain fill embankment under repeated train loads. The temperature field of the embankment in the permafrost area was set at the current geothermal conditions. As a result, the permanent deformation of the embankment under train loading was obtained, and the permanent deformation under the train loads to the total embankment deformation was also analyzed.  相似文献   

基于并行计算的海量点云狄洛尼构网方法探讨     

李坚 《测绘科学》2015,(11):137-141

针对现有Delaunay三角网购网方法研究的不足,文章提出一种基于并行计算的海量点云Delaunay方法:根据Delaunay分治构网的思想,将Delaunay构网分为数据分割、构建子网和子网合并3个步骤;设计了一种自适应的四叉树结构来分割和映射数据文件,并依据OpenMP并行标准中的Fork/Join并行模式,分层执行构网运算和合并运算;最后,使用一种改进的WFM-JLP调度算法来调度构网和合并运算以取得较好的负载均衡。实验证明:该方法能较好地降低算法的运行内存,减少运算时间。  相似文献   

A crack in the facade? Situating Singapore in global flows of electronic waste          下载免费PDF全文

Josh Lepawsky  Creighton Connolly 《Singapore journal of tropical geography》2016,37(2):158-175

Singapore is alleged to be a key node in global flows of e‐waste prohibited under the Basel Convention. We combine a close reading of the Convention and related documents with findings from nonparticipant observation of and interviews with Singapore‐based traders of discarded electronics. The case offers both important conceptual and empirical findings for future studies of territory in market‐making activity. Conceptually, our research suggests that it may be analytically useful in such studies to conceptualize territory without presupposing that it is generated as a result of separate domains or logics such as ‘the political’ or ‘the economic’. Empirically, we find that the regulatory framework of the Convention, combined with the action of traders based in Singapore, generates a territorialization of the city‐state such that it operates as a crack in the regulatory edifice of the Convention, even as Singapore lawfully fulfils its obligations to it. Moreover, allegations premised on the role of Singapore as a facilitator of global e‐waste dumping misrepresent its crucial role as a conduit of electronic equipment for the significant reuse markets elsewhere in Southeast Asia and beyond. The case indicates that the allegations against Singapore hinge on the city‐state being territorialized as a ‘developing country’.  相似文献   

合肥市生活垃圾处理项目续建工程水文地质工程地质勘察实录     

林宾  王小勇 《安徽地质》2007,17(3):203-207

合肥市生活垃圾处理项目是安徽省内规模最大的垃圾处理填埋场,工程区地质条件复杂,防渗设计要求严苛,经过工程地质水文地质测绘、钻(静)探、取样测试、地球物理勘探、原位测试、水文地质试验等综合手段勘察,取得了科学准确的参数,对建筑物的地基持力层的选择、设计参数、防渗处理等提出了经济合理的结论和建议,为优化设计、节省投资、安全施工奠定了基础,取得了良好的经济效益及社会效益,同时也积累了同类型项目在花岗岩地区复杂地质条件下的水文地质工程地质勘察经验.  相似文献   

浮式风机极限载荷与疲劳载荷对比分析     

张友文  王迎光 《海洋工程》2015,33(3):57-62

根据IEC61400-3设定工况,采用NREL开发的5 MW风机基础模型,应用FAST,以Aero-Hydro-Servo-Elastic耦合仿真技术对风机进行研究。对时域仿真得到的短期载荷,应用分块极大值法联合Gumbel分布外推计算风机极限载荷;以雨流计数法、线性累积损伤理论和S-N曲线为理论基础应用MLife软件,计算风机疲劳载荷。对比分析不同工况下浮式风机、近海单桩风机和陆上风机的极限载荷与疲劳载荷,进而探讨影响浮式风机动态响应的因素。结果表明,对于陆上风机和近海单桩风机,风是其主要载荷来源;而波浪是浮式风机主要载荷来源。对风机进行设计要根据特定海域统计的海洋气候条件,避免风机及其支撑结构的固有频率与波浪频率近似而产生共振;风机制造装配在一定误差范围内,质量不平衡对风机载荷几乎没有影响。  相似文献   

Modelling of rutting of two flexible pavements with the shakedown theory and the finite element method   总被引：1，自引：0，他引：1  

Cyrille Chazallon  Georg Koval  Pierre Hornych  Fatima Allou  Saida Mouhoubi 《Computers and Geotechnics》2009

This paper presents a finite element program, for the modelling of rutting of flexible pavements. In its present version, the program incorporates a permanent deformation model for unbound granular materials based on the concept of the shakedown theory developed by Zarka for metallic structures under cyclic loadings and has been used to estimate the permanent deformations of unbound granular materials (UGM) subjected to traffic loading. The calculation is performed in two steps: the first step consists in modelling the resilient behaviour of the pavement in 3D, using non-linear elastic models, to determine the stress field in the pavement. Then stress paths are derived and used to calculate the permanent deformations and the displacements, using a Drucker–Prager yield surface. An application to the prediction of the permanent deformations of experimental pavements with an unbound granular base, tested on the LCPC pavement testing facility is presented.  相似文献   

Geochemical study of groundwater mineralization in the Grombalia shallow aquifer,north-eastern Tunisia: implication of irrigation and industrial waste water accounting   总被引：2，自引：0，他引：2  

Amor Ben Moussa  Kamel Zouari  Naceur Oueslati 《Environmental Geology》2009,58(3):555-566

Hydrochemistry of groundwater is largely determined by both natural processes, such as dissolution, cation exchange, mixing, evaporation; and anthropogenic activities, which can affect the aquifer systems by contaminating them or by modifying their hydrological cycle. Both natural and anthropogenic processes vary in time and space; which is reflected in groundwater hydrochemistry variation. The objective of this study is the determination of the main hydrogeochemical processes that affect the quality of shallow groundwaters in the Grombalia basin, located in the Cap Bon Peninsula, north-eastern Tunisia. In this area, the chemical composition of groundwater is mostly characterized by Na–Cl–NO₃–Ca water type which reveals the implication of natural and anthropogenic major factors. Natural factors are dissolution of evaporatic minerals, i.e. halite and gypsum and cation exchange with clays, while anthropogenic factors are pollution with industrial Sr-rich waste water and return flow of irrigation water, highly contaminated by MgSO₄ and methyl-bromide fertilizers.  相似文献