基于核密度分析与关联规则的天水盆地黄土滑坡规律研究     

胡良柏 《测绘与空间地理信息》2022,45(1):30-32,39

滑坡灾害是天水盆地最严重的地质灾害.本文基于已有的灾害数据,利用GIS叠加分析的结果作为滑坡灾害点的属性特征,与灾害点的核密度分析结果建立关联规则,找出高风险滑坡区域与相关属性特征的关联关系.结果表明:天水盆地的滑坡灾害与降水条件、地层岩性以及地形坡度有较强的关联关系.  相似文献   

An extended cellular automaton using case‐based reasoning for simulating urban development in a large complex region     

Xia Li  Xiaoping Liu 《International journal of geographical information science》2013,27(10):1109-1136

Rule‐based cellular automata (CA) have been increasingly applied to the simulation of geographical phenomena, such as urban evolution and land‐use changes. However, these models have difficulties and uncertainties in soliciting transition rules for a large complex region. This paper presents an extended cellular automaton in which transition rules are represented by using case‐based reasoning (CBR) techniques. The common k‐NN algorithm of CBR has been modified to incorporate the location factor to reflect the spatial variation of transition rules. Multi‐temporal remote‐sensing images are used to obtain the adaptation knowledge in the temporal dimension. This model has been applied to the simulation of urban development in the Pearl River Delta which has a hierarchy of cities. Comparison indicates that this model can produce more plausible results than rule‐based CA in simulating this large complex region in 1988–2002.  相似文献   

翡翠中共生矿物含量对翡翠定名的影响     

韩辰婧  王雅玫  刘洋 《地质科学译丛》2013,(1):28-36

目前翡翠市场上出现了越来越多含共生矿物的翡翠品种,给翡翠定名带来了一定的困难。针对这一问题,选取了具有代表性的原石样品进行了研究。研究方法包括实测样品的相对密度,X嘣线粉末衍射（XRD）物相量化分析,以及利用红外光谱观察共生矿物出现的机率。根据所含的共生矿物种类,翡翠可分为两类,一类为含钠长石的样品,另一类为含霞石和角闪石的样品。在反射光下,钠长石为透明玻璃状,而霞石呈磨砂玻璃状。基于上述鉴别特征,即可区分出钠长石和霞石。两类样品的相对密度都随共生矿物含量的增加逐渐降低,而理论密度值与实际测试密度值略有不同。结合上述研究结果以及岩石学命名规则,笔者探讨并提出了一套关于含共生矿物翡翠的命名规则。  相似文献   

小兴安岭翠宏山地区矽卡岩型铁多金属矿成矿特征及区域预测          下载免费PDF全文

张东才  董秋花  刁萍 《江苏地质》2013,37(3):444-450

小兴安岭是黑龙江中部重要的多金属成矿区带,成矿潜力巨大。通过对翠宏山铁多金属典型矿床的研究,建立了区域预测概念模型,总结了该区铁多金属矿的控矿规律,确定了预测要素。在此基础上运用MRAS软件,圈定了3个最小预测区,并对预测区进行了地质评述,认为翠宏山铁多金属矿外围仍是寻找矽卡岩型铁多金属矿较为有利的地区。  相似文献   

土钉加固黏性土坡加载的离心模型试验研究   总被引：1，自引：0，他引：1  

曹洁  张嘎  王丽萍 《岩土力学》2012,33(6):1696-1702

进行了不同坡度土钉加固边坡坡顶加载的离心模型试验,观测了土坡的破坏过程并测量土坡的位移场,研究了土钉加固黏性土坡的承载力、变形和破坏规律以及坡角对其破坏规律的影响。试验结果表明,坡顶荷载的增加引起土坡变形的增加,变形的集中产生和发展导致滑裂面的形成并使土坡发生破坏。土钉变形规律受加载阶段和加载底板的综合影响,坡顶荷载越大,接近坡顶的土钉弯曲挠度越大,钉土间的相互作用越强。土坡的坡角越大,承载力越低,土体呈现出更显著的向坡面位移的趋势。  相似文献   

Advances in terrestrial system research in China   总被引：1，自引：1，他引：0  

Shaohong Wu  Yunhe Yin  Du Zheng  Qinye Yang  Haoyu Deng 《地理学报(英文版)》2016,26(7):791-802

Land surface is of spatial-temporal heterogeneity. Terrestrial system (TS) comprehensively studies on land surface and physical regionalization objectively describes geographical zonation of the system. China has a vast area with apparent spatial variations in resources and environmental conditions, which highly influence on socio-economic development. In this paper, progress of the TS studies in China is overviewed and research priorities in the near future are prospected. Since the 1950s, China has paid great attention to the TS study as its socio-economic development, and conducted research on physical geographical regionalization, eco-geographical regionalization and comprehensive regionalization. Along with the deepening of global change research, dynamics of TS have been highly concerned. During the studies, methodology has been developed from qualitative research of integration of experts’ brainpower gradually to quantitative research based on field observation and experiments of the natural processes, including physical, chemical and biological processes, as well as application of information technology and mathematical simulation. In the near future, TS would combine with the ideology, objectives and key researches of Future Earth program, to focus on the mechanism and regional effects of interaction among land surface elements, the response of TS to global change, the quantitative recognition on regional unit boundary, and the application to TS in sustainable socio-economic development.  相似文献   

西昆仑落石沟一带铅锌矿成矿特征及区域预测     

徐仕琪  冯京  田江涛  赵同阳 《吉林大学学报(地球科学版)》2013,43(4):1190-1199

西昆仑是新疆西南部重要的成矿区带,落石沟矿带已发现铁多金属、铜、铅锌矿（床）点16处,成矿潜力巨大。从区域地质成矿背景、控矿构造、沉积建造分析入手,以宝塔山、落石沟铅锌矿作为典型矿床,结合重力、磁法、化探、遥感等信息建立了区域预测概念模型,初步总结了该区铅锌矿的控矿规律,确定了区域宏观与微观预测要素。在此基础上运用证据权法采用地质、地球化学、地球物理、遥感等12个变量进行了成矿后验概率计算,后验概率最大值为0.854 022,最小值为0.000 015。按3级分类,成矿最为有利地区后验概率为0.643 428,较为有利地区后验概率为0.432 833,一般有利地区后验概率为0.222 238。按一定颜色进行分区,根据后验概率图圈定了5个最小预测区。对预测区进行了地质评述,结果表明,西昆仑落石沟一带是寻找层控-热液型铅锌矿较为有利的地区。  相似文献   

Damping formulation for nonlinear 1D site response analyses   总被引：2，自引：0，他引：2  

Camilo Phillips  Youssef M.A. Hashash 《Soil Dynamics and Earthquake Engineering》2009

Measurements and observations of ground shaking during large earthquakes have demonstrated the predominant role of site effects in the response of infrastructure during a seismic event. Despite significant efforts to model the hysteretic response and nonlinearity of soils due to medium and large ground motions, the most widely accepted nonlinear site response methods are not able to represent simultaneously the changes of stiffness and energy dissipation (damping) observed in both laboratory tests and during earthquake events. This paper presents two new soil damping formulations implemented in nonlinear one-dimensional site response analysis for small and large strains. The first formulation introduces an approach to construct a frequency-independent viscous damping matrix which reduces the over-damping at high frequencies, and therefore, the filtering at those frequencies. The second formulation introduces a reduction factor that modifies the extended Masing loading/unloading strain–stress relationship to match measured modulus reduction and damping curves simultaneously over a wide range of shear strains. A set of examples are introduced to illustrate the effect of using the two proposed formulations, separately and simultaneously, in nonlinear site response analyses.  相似文献   

西藏伦坡拉盆地油页岩特征及分布规律     

谢尚克  杜佰伟  王剑  彭清华  郑博 《吉林大学学报(地球科学版)》2014,44(6):1760-1767

伦坡拉盆地有较大规模的油页岩出露,根据油页岩工业划分标准,伦坡拉油页岩属于含油率较高的高灰分、特低硫型油页岩。伦坡拉油页岩主要发育于丁青湖组之中,形成于半深湖-深湖相沉积环境。通过岩相古地理研究,发现伦坡拉油页岩厚度受沉积相带控制,呈规律性展布,从深湖-半深湖-浅湖-滨湖呈环带状由中心向四周逐渐减小的变化趋势,位于盆地中央半深湖-深湖相区的伦坡日、蒋日阿错地区油页岩厚度相对较大,具有广阔的开发利用前景。  相似文献   

燃气GIS地理网络模型构建技术研究   总被引：5，自引：2，他引：3  

杨亮洁  牟乃夏 《测绘科学》2006,31(2):72-73,80

在分析城市燃气地理网络的特点、构成要素、各要素之间关系的基础上,将燃气地理网络抽象为物理网络、几何网络和逻辑网络三个层次。介绍了三个层次网络模型的特点与本质联系,提出了燃气网络构造的拓扑规则(边-边规则、边-结点规则等),给出了燃气网络构建的流程和实现框架。并以十堰市燃气GIS的网络模型为例,说明了燃气地理网络模型的构建技术与应用。  相似文献