The complex nature of creep movements on steeply sloping ground in Southern Rwanda     

Jan Moeyersons 《地球表面变化过程与地形》1988,13(6):511-524

Long term soil creep motion is often represented as a type of laminar flow, with velocity vectors parallel to the slope and constant in time. Records on a hillslope in Southern Rwanda reveal that creep movements there compare more with turbulent flow, characterized by a A1 humic horizon superlayer, creeping over a subsoil affected by more irregular creep deformation.  相似文献   

建筑用铅芯橡胶隔震支座温度性能研究   总被引：5，自引：0，他引：5  

刘文光  杨巧荣  周福霖 《世界地震工程》2003,19(2):39-44

详细研究了建筑隔震结构中铅芯橡胶隔震支座的温度特性。内容包括三个方面：首先是一定温度条件下进行的温度相关性试验，温度范围由—20℃至40℃；其次进行了高温燃烧并经冷却后的基本性能及界限性能试验；最后研究完成了恒温100℃状态下老化185小时和240小时的长期性能试验。在试验结果的基础上，提出了支座屈服后刚度及屈服荷载的温度修正方程。  相似文献   

The shapes of cold, high mountains in sedimentary rocks     

D. M. Cruden   《Geomorphology》2003,55(1-4):249

Terzaghi (Geotechnique 12 (1962) 251) and Young (Young, A., 1972. Slopes. Oliver and Boyd, Edinburgh, 288 pp.) described the stable forms of slopes in sedimentary rock masses, assuming penetrative discontinuities, which are parallel to bedding and joints which are perpendicular to bedding. The only movements considered were slides along bedding. Experience in the Canadian Rockies indicates that the cohesionless rock masses that exist at or above tree line may also move by toppling, buckling and sliding along joints. These processes also act to limit the inclinations of stable slopes. Rock strength is a factor in the critical height of a slope that buckles. The processes can be represented as fields on a process diagram, a plot of slope inclination against bedding dip, using the basic friction angles of the rocks present.The process diagram also separates five common mountain peak shapes, which form on homoclinal sequences of beds. Castellate and Matterhorn mountains occur in sub-horizontal beds, cuestas develop in gently to moderately dipping beds. Hogbacks formed in moderately to steeply dipping beds have similar slope angles on both cataclinal and anaclinal slopes. Dogtooth mountains occur in steeply dipping sub-vertical beds.  相似文献   

辽宁省老年宜居社区人居环境评价   总被引：2，自引：2，他引：0  

张春梅  李雪铭 《地理科学》2021,41(1):92-99

在国内外学者研究基础上,立足中国国情,基于老年宜居社区内涵,探索性地构建了老年宜居社区人居环境评价指标体系。基于多源数据,选择辽宁省149个城市社区进行实证研究,结果表明：① 从整体上看,参评社区老年宜居环境质量较差,绝大多数的社区尚未对已经到来的老龄化社会做好充分的准备;② 从空间分布特征来看,整体呈现“中部?南部凸起,西北?北部凹陷”的分布格局,大连市和沈阳市形成“双核”引领辽宁省老年宜居环境质量的发展。③ 分系统研究表明,设施系统的质量最差。各城市在分系统上的优劣势有所差异。④ 从公共指标与专项指标的对比来看,公共指标评价值明显高于专项指标,社区人居环境建设存在代际不公平现象。  相似文献   

老龄化背景下候鸟旅游移民迁移驱动力 ——以三亚为例     

段圣奎  苏勤 《热带地理》2021,41(2):441-448

以三亚为例,基于对256位候鸟旅游移民的实地调研,采用因子分析及方差分析等方法,探讨了候鸟旅游移民迁移驱动力的结构、强度及群体差异。结果表明：1）三亚候鸟旅游移民经济收入和文化水平相对较高,但也存在显著的内部差异;2）三亚候鸟旅游移民迁移驱动力由风景环境、社会资本、社会象征、城市服务、生活方式、家庭氛围及健康养生等7个因子组成,其中,健康养生居得分最高,城市服务得分最低;3）与国外主要对“美好生活”的积极追求不同,三亚候鸟旅游移民多受年龄增长带来的健康问题所驱使;4）文章揭示了“旅游休闲—日常生活”这一动力连续体,反映了三亚候鸟旅游移民迁移驱动力的复杂性;5）不同性别、文化程度、年龄、旅居时间的三亚候鸟旅游移民迁移驱动力具有一定差异,尤其是不同文化程度及年龄,意味着收入水平、消费观念及健康状况的不同,对其驱动力影响较大,在社会资本方面区别显著。  相似文献   

中国人口老龄化区域差异及驱动机制研究   总被引：2，自引：1，他引：1  

吴连霞  赵媛  吴开亚  郝丽莎  王玉娟 《地理科学》2018,38(6):877-884

基于中国第五、六次人口普查数据,分析中国省域人口老龄化的程度、速度、社会经济影响、空间差异及其驱动机制。结果表明：① 2000~2010年中国人口老龄化处于初级老龄化阶段且不断加深,区域差异缩小,东部地区低速增长,中西部地区老龄化与养老负担快速增加。老年人口密度属较低密度区,从东向西呈梯度降低。② 中国省域人口老龄化程度及空间布局是人口自然增长、人口机械增长、经济水平等因素相互调节与空间分异的综合结果。③ 各机制系数空间异质性的综合作用促使老龄化大致由南北向分异转变为东西向分异的空间格局。省际人口迁移从根本上制约如今的中国人口老龄化空间格局。  相似文献   

Linked turbidite–debrite resulting from recent Sahara Slide headwall reactivation     

Aggeliki Georgiopoulou  Russell B. Wynn  Douglas G. Masson  Michael Frenz 《Marine and Petroleum Geology》2009,26(10):2021-2031

The northwest African margin has been affected by numerous large-scale landslides during the late Quaternary. This study focuses on a recent collapse of the Sahara Slide headwall and characterises the resulting flow deposit. Core and seismic data from the base of the upper headwall reveal the presence of blocky slide debris, comprising heavily deformed hemipelagic slope sediments. The blocky slide debris spilled over a lower headwall 60 km downslope and formed a thick transparent debris flow unit. Cores recovered 200–250 km farther downslope contain a surficial turbidite that is interpreted to be linked to the headwall collapse event based on timing and composition. One core located approximately 200 km from the headwall scar (C13) contains debrite encased in turbidite. The debrite comprises sheared and contorted hemipelagic mudstone clasts similar as those seen in the vicinity of the Sahara Slide headwall, and lacks matrix. This debrite pinches out laterally within 25 km of C13, whereas the accompanying turbidite can be correlated across 700 km of the northwest African margin. The linked turbidite–debrite bed is interpreted to have formed through recent failure of the steep Sahara Slide headwall that either 1) generated both a debris flow and a turbidity current almost simultaneously, or 2) generated a debris flow which with entrainment of water and progressive dilution led to formation of an accompanying turbidity current.  相似文献   

临汾盆地末次间冰期以来地貌演化的构造和气候响应   总被引：1，自引：1，他引：0  

胡小猛  杨景春 《地质力学学报》2001,7(2):176-180

野外调查发现,末次间冰期(MIS₅)以来临汾盆地普遍发育了一级冲湖积台地(T₃)、一级湖蚀台地、两级堆积阶地(T₂、T₁).利用黄土磁化率地层定年法、TL测年法,确定这些台地或阶地的年龄分别为130kaBP、130kaBP~52kaBP、52kaBP和9kaBP.分析构造和气候因素对河湖地貌发育的影响规律,得出T₃台地的形成是130kaBP的区域构造抬升的结果;T₂、T₁阶地的出现是河流响应晚更新世以来气候变化的产物;湖蚀台地的存在反映了汾河下游黄河三门峡河段可能曾因古崩塌滑坡而被堵塞过。   相似文献   

富宁那坪金矿成因及找矿标志   总被引：1，自引：0，他引：1  

陈新敏  施建萍  邹蓉蓉  杨苏焕 《云南地质》2011,30(1):15-17

那坪金矿位于区域磁性较弱或强、弱磁性过渡地带及重力高异常边部。矿体产于中泥盆统坡折落组(D2p)与印支期辉绿岩体内、外接触带及其附近的构造破碎带中,脉状,构造角砾岩型氧化金矿石。主要控矿因素为北西向组断裂,以及印支期钛辉辉长辉绿岩体。  相似文献   

青岛文昌鱼（Branchiostomabelcheri tsingtauense）染色体G类带型研究   总被引：1，自引：0，他引：1  

牟洪善  王昌留  李金萍 《海洋与湖沼》2011,42(4):597-602

以青岛文昌鱼的晚期囊胚和早期原肠胚的胚胎细胞为实验材料,利用低渗处理、空气干燥法制备染色体玻片标本。在此基础上,为进一步探索显示青岛文昌鱼染色体G带的新方法,采用片龄、蛋白酶K和胰蛋白酶显带技术对青岛文昌鱼的染色体进行了初步研究,显示了青岛文昌鱼染色体的G类带型,绘制了青岛文昌鱼染色体的G类带型模式图,并对三种G类带型...  相似文献