An alternative depth-integrated formulation for granular avalanches over temporally varying topography with small curvature     

Yih-Chin Tai  Chih-Yu Kuo  Wai-How Hui 《地球物理与天体物理流体动力学》2013,107(6):596-629

An alternative formulation is proposed for deriving depth-integrated equations for gravity-driven granular avalanches over a non-trivial topography with small curvature. The coordinate system of Bouchut and Westdickenberg (2004 Bouchut, F and Westdickenberg, M. 2004. Gravity driven shallow water models for arbitrary topography. Commun. Math. Sci., 2: 359–389. [Crossref] , [Google Scholar]) is combined with the unified coordinate (UC) method, so that it can evolve in accordance with the entrainment–deposition processes at the basal surface. The resultant mass and momentum equations are formulated as a conservation system of the Cartesian components of the conservative physical variables. The motion of the flows is driven by the basal topography-induced pressure, pressure gradient, and resisted by the basal friction. The best benefit of this formulation is that it greatly simplifies the computation of the varying coordinate orientations. The features and advantages of this formulation are illustrated by the sliding-mass examples where we simulate the motion of a finite mass of granular material sliding down an inclined chute, running through a transition zone, and being deposited onto a horizontal plane.  相似文献   

水泥土搅拌桩在垃圾填埋场地基处理中的应用     

刘刚  台运好  华伟 《岩土工程技术》2012,26(2):106-108,F0003

水泥土搅拌桩作为加固软土地基的一种成熟方法,适用于多种成因的饱和软粘土与粉土等地基。通过工程实例,介绍了水泥土搅拌桩在用于垃圾填埋场复合地基中,提高地基承载力与减少地基沉降量,保证垃圾堆体及地基整体稳定的作用,供类似工程参考。  相似文献   

Correlating mass physical properties with ALOS reflectance spectra for intertidal sediments from the Ba Lat Estuary (northern Vietnam): an exploratory laboratory study     

Nguyen Thi Ngoc  Katsuaki Koike  Nguyen Tai Tue 《Geo-Marine Letters》2013,33(4):273-284

Characterization of the sediment composition of tidal flats and monitoring of their spatiotemporal changes has become an important part of the sustainable management of coastal environments. To accurately classify sediments through remote sensing, a comprehensive understanding of sediment reflectance spectra is indispensable. The present laboratory-based study explores the performance of the high spatial resolution (10?×?10 m) Advanced Land Observing Satellite (ALOS) launched in 2006. Relationships between reflectance spectra (bands 1 to 4) and four typical mass physical properties were investigated under wet and dry experimental conditions for intertidal sediments sampled near the Ba Lat Estuary in northern Vietnam. Reflectance in the near-infrared region corresponding to ALOS band 4 (0.76–0.89 μm) was found (1) to have a strong negative correlation with sand content (dry wt%) under both wet and dry conditions (linear correlation coefficient r?=?–0.7859 and –0.8094, respectively), (2) to increase with decreasing relative water content (%) in a given sediment type (r?=?–0.7748 to –0.9367 for mud, sandy mud, muddy sand, and sand), (3) to have a positive correlation with organic matter content (r?=?0.7610 and 0.6460 under wet and dry conditions for contents >0.20 dry wt%), and (4) to be insignificantly correlated with mineral composition assessed in terms of contents (wt%) of quartz, clay minerals, and mica group minerals. Positive relationships between reflectance and water content for the pooled data of all sediment types (r?=?0.6395) or organic matter content contrast with previous findings, and can be attributed to close interrelationships between these properties and the predominance of sand content as controlling factor of reflectance. This study clarifies that ALOS band 4 provides the most useful imagery for intertidal monitoring because its reflectance, as simulated using the laboratory data, shows the strongest correlation with sand content. In a next step, these experimental findings should be verified by identifying the reflectance relationships at satellite image scales, and also considering the effects of other tidal flat features on reflectance, such as microtopography and biological surface characteristics.  相似文献   

喀斯特生态环境敏感性评价指标分级方法研究——以都匀市土地利用类型为例   总被引：4，自引：2，他引：2  

李荣彪  洪汉烈  强泰  杨广斌  安裕伦  李阳兵 《中国岩溶》2009,28(1):87-93

应用数学、统计学等方法建立"比较矩阵"分析模型,对喀斯特地区生态环境敏感性评价指标的分级方法进行研究.与此同时,以都匀市土地利用类型为例,从生物多样性、系统承载力、环境容量、气候调节、物质循环与能量流动、水土保持与流失、环境污染、土地退化等11个指标来对13种土地利用类型分别做比较分析与敏感性量化,然后进行敏感性排序和有序聚类分级,并借助GIS软件绘成都匀市土地利用类型生态敏感等级分布图.研究结果认为,Ⅰ级敏感的土地利用类型包括灌木林地、有林地,Ⅰ级敏感包括天然草地、稻田、园地、水域,Ⅲ级敏感包括旱地、陵墓地,Ⅳ级敏感包括城镇、公路、农村居民点,Ⅴ级敏感包括独立工矿用地、未利用地.   相似文献   

三峡库区第三期地质灾害治理项目即将启动     

董泰 《国际地震动态》2005,(4):47-47

经我国13位地质专家分析确定的长江三峡库区195m处前缘高程、156m水位线以下的地质灾害治理项目即将启动。这批地质灾害治理项目是三峡库区地质灾害治理的第3期,总投资达65亿元人民币,主要是为了确保库区地质灾害不影响三峡工程如期蓄水至156m,保护移民安全,避免蓄水后水下工程难以施工或增大投资。  相似文献   

上海抗震能力Ⅶ度,重要建筑都装有强震记录仪器     

董泰 《国际地震动态》2005,(4):47-47

经我国13位地质专家分析确定的长江三峡库区195m处前缘高程、156m水位线以下的地质灾害治理项目即将启动。这批地质灾害治理项目是三峡库区地质灾害治理的第3期,总投资达65亿元人民币,主要是为了确保库区地质灾害不影响三峡工程如期蓄水至156m,保护移民安全,避免蓄水后水下工程难以施工或增大投资。  相似文献   

石英脉型钨矿成矿研究进展   总被引：1，自引：0，他引：1       下载免费PDF全文

许泰  刘雪芬  张巨峰  杨峰峰 《地质找矿论丛》2019,34(2):196-200

我国钨矿的储量、产量、消费量和出口量均处于全球领先地位,尤其是石英脉型钨矿床研究成果最为丰富。本文通过大量查阅国内外有关石英脉型钨矿的文献资料,对石英脉型钨矿的成矿研究成果和观点进行综合评述。石英脉型钨矿在我国各个成矿带均有分布,其空间分布和区域构造单元息息相关,所处的区域构造活动一般都很强烈,经历多次叠加构造运动。钨矿床产在震旦寒武系地层中,特别是在寒武系地层最多。成矿物质主要来源是岩浆热液,岩浆活动频繁为成矿热液的形成创造了必要的前提条件,但也有部分成矿物质源于围岩。石英脉型钨矿成矿模式以"五层楼+地下室"成矿模式最具影响力和实际意义,开创了模式找矿的先河。  相似文献   

青海循化盆地新近纪磁性地层学   总被引：4，自引：4，他引：0  

季军良  张克信  强泰  寇晓虎  陈奋宁  徐亚东  路晶芳  林启祥 《地球科学》2010,35(5):803-810

青藏高原东北部是研究高原隆升和东亚季风演化的重要地区.通过对青藏高原东北部循化盆地西沟剖面新近纪河湖相沉积的磁性地层学研究, 建立了西沟剖面约14.6~5.0 Ma沉积物的磁极性年代框架.沉积相的分析表明, 循化盆地在约14.6~5.0 Ma期间总体上处于充填萎缩阶段.西沟剖面巨厚层砾岩首次出现的时间约为7.3 Ma前, 应是青藏高原东北部快速隆升的沉积响应.这与青藏高原在约8.0 Ma前快速隆升的时间相近, 进一步说明约8.0 Ma前青藏高原的构造隆升具有准同时性.   相似文献   

异常压力对有机质的抑制作用及其石油地质意义   总被引：2，自引：1，他引：1  

李会军  吴泰然  郝银全  张秀珠  马宗晋 《沉积学报》2004,22(4):737-742

板桥凹陷异常压力发育,在板深35井中发现有机质的演化明显的受到了超压的抑制作用,具有和活化能、热导率、水动力等因素造成的热演化异常明显不同的特征。综合地质、地球化学分析表明,异常孔隙流体压力对有机质热演化的抑制作用是有条件的,在超压早期发育、高原始有机质丰度和高有机质热演化产物滞留的情况下超压对有机质的演化具有明显的抑制作用,超压对有机质演化的抑制作用在深层勘探方面具有重要的意义。  相似文献   

煤田陷落柱氡气场的数值计算及空间形态分布特征   总被引：8，自引：0，他引：8       下载免费PDF全文

刘泰峰  安海忠  亢俊健  周瑞 《地球物理学报》2004,47(1):171-177

根据流体场的扩散理论和对流理论,建立了扩散系数与对 流速度为常量或变量情况下的氡气场三维状态方程;对于陷落柱柱体侧面有源氡气场和柱体 体内有源氡气场两种理论模型,给出了不同系数和边界条件下的数值解的形式. 针对模型的 特点及其边界条件用差分法分别进行了数值计算,结果表明陷落柱氡气场的空间形态 分布特征. 野外实测和模型试验的结果相互吻合.  相似文献