植被淹没程度对坡面流水动力学特性影响          下载免费PDF全文

杨帆  张宽地  杨明义  杨婕 《水科学进展》2016,27(6):832-840

为深入揭示植被覆盖条件下坡面水流结构的内在规律,采用水槽模拟试验,系统研究了植被处于淹没及非淹没工况下淹没度对坡面流水动力学特性的影响。研究结果表明:坡度一定条件下,平均流速和雷诺数与淹没度均成正相关关系;柔性植被覆盖下,水流流型由缓流区过渡到急流区,综合阻力系数随淹没度的增加而减小,刚性植被覆盖条件下水流流型均处于缓流区;综合阻力系数呈单驼峰形式变化;峰值处淹没度为0.9,淹没度对相对摩阻流速的影响与其对阻力系数呈相反变化趋势,基于淹没度的阻力计算经验公式决定系数均达到0.97以上;由于淹没度对各水动力学参数的影响受制于坡度,在坡面水土保持中应根据山区坡度和水深选择适当的植被高度。  相似文献   

Effect of dry density,soil texture and time-spatial variable water content on the soil thermal conductivity     

Saeid Nikoosokhan  Hossein Nowamooz  Cyrille Chazallon 《Geomechanics and Geoengineering》2016,11(2):149-158

Study of the heat transfer process in saturated and unsaturated soils requires, basically, a relationship between thermal conductivity and the characteristics of the soil, such as water content, dry density and texture of the soil. This study intends to produce a generic model that can predict soil thermal conductivity with the help of easily measurable parameters. The proposed model is first calibrated using measured thermal conductivities from literature data. In order to validate the proposed model the predicted thermal conductivity of this proposed model as well as existing ones are compared with the measured thermal conductivity in literature for different soils. Validation of the proposed model was also performed on our experimental results obtained for a compacted Misillac sand and in-situ clay loam soils. The results show an average of 15% improvement in prediction accuracy for the proposed model compared to the existing models, considering all soil textures. Moreover, we perform a model to estimate thermal conductivity over time throughout the profile of soil in the context of seasonal variation of temperature. The proposed model shows an important effect of heterogeneity on the thermal conductivity variations of a double layered soil.  相似文献   

地理国情与复杂系统   总被引：1，自引：0，他引：1  

王家耀  谢明霞 《测绘学报》2016,45(1):1-8

研究地理国情复杂系统的意义在于合理表达"资源—环境—生态—经济—社会"系统的综合复杂关系。针对我国地理国情统计分析工作所面临的研究内容不统一、范围不一致、目标不明确等问题,本文基于复杂系统理论和协调度分析方法,分别从概念、理论与方法的角度探讨并设计了相应的解决途径。通过对地理国情、地理国情普查、地理国情统计分析的概念以及三者间的关系分析,明确和界定了地理国情的统计内容和分析范围,具体化了地理国情统计分析目标;对比分析了地理国情与复杂系统的基本特征,以及协调度分析与地理国情统计分析的目标一致性,提出了地理国情复杂系统的概念,并对其进行了定量描述;复杂系统理论为地理国情统计分析提供了新的理论指导,协调度为地理国情统计分析提供了新思路。在此基础上设计了地理国情复杂系统的测度方法和决策分析方案。通过地理国情复杂系统协调度从宏观上分析总体趋势,结合各子系统间协调度和单系统协调度从微观上确定修复方向,并制定具体改进策略,从而实现地理国情统计分析的宏观目标。  相似文献   

Delineation of Haigou gold metallogenic province and its metallogenic prospection     

《世界地质(英文版)》2016,(1):41-47

Based on the accumulated data for the gold deposits in the central Jilin Province in recent years and our understanding of the gold metallogenic province,the Haigou gold metallogenic province is delineated and the denudation degree of gold deposits in this province is discussed. The potential and the ore-searching direction of the province are also considered. The Haigou gold metallogenic province occurs as an independent province with low denudation degree and high ore-producing potential. Regional fault belts and small basic intrusions are two ore-constrains and could serve as the ore-searching indictors in the province.  相似文献   

Hydrocarbon accumulation model for Neogene traps in the Chengdao area,Bohai Bay Basin,China     

《Marine and Petroleum Geology》2016

Chengdao is an offshore area in the Bohai Bay Basin that contains approximately 25.7 × 10⁸ bbl of oil and gas reserves within the sandstone reservoirs in Neogene strata. However, previous predictions of hydrocarbon accumulation in Neogene traps are inaccurate, resulting in a current failure rate of 50% when drilling for hydrocarbons in this area. To build an improved exploration model for Neogene traps, we select 92 traps from Neogene strata in the Chengdao area to quantify the filling degree, which is an indicator of hydrocarbon accumulation efficiency. The quantified filling degree is based on actual geological and exploration data and differs significantly among various trap types. The filling degree of traps also varies significantly with their structural locations and decreases generally from the northwest to the southeast along the Chengbei Fault zone. Vertically, the filling degree is highly heterogeneous, initially increasing from the bottom to the middle of Neogene strata and then decreasing towards the top of the strata. These Neogene hydrocarbon reservoirs are sourced from the Paleogene, and as they lay vertically away from the source rocks, their hydrocarbon enrichment is constrained largely by hydrocarbon migration distance and vertical migration pathways. The sealing capacity of faults and cap rocks, sandbody orientation and reservoir sedimentary facies determine the maximum column height, which in turn affects the amount of hydrocarbon accumulation within these traps. A scatter plot analysis of individual controls and volumetric filling for each trap type is compiled using multivariate linear regression analysis to quantify controls and the dominant control of hydrocarbon accumulation is determined.  相似文献   

南极普通球粒陨石风化等级的重新厘定     

尚颖丽  李世杰  王世杰  李雄耀  李阳 《岩石学报》2016,32(1):71-76

在南极格罗夫山普通球粒陨石的风化等级划分中出现了和Wlotzka(1993)标准矛盾的现象。部分普通球粒陨石的金属和陨硫铁氧化不足20%,然而硅酸盐却发生了蚀变。如果考虑金属的氧化量,这种风化程度应为W1,如果考虑硅酸盐的蚀变,这种风化程度应为W5。对于存在如此大的差异本文给出了折衷的解决办法——对金属和硅酸盐同时进行风化等级划分。金属的风化等级划分为W_m0-W_m4五个,硅酸盐风化等级划分为W_s0-W_s3四个。依据新方案,GRV 021588、021636、021772和021957等4块无法用Wlotzka(1993)标准来确定风化等级的陨石的风化等级均为W_m1-W_s1。而陨石GRV 023312的风化等级为W_m3-W_s0,其相当于Wlotzka(1993)标准中的W3。  相似文献   

成矿预测的模糊综合评判法     

姜效典 《中国海洋大学学报(自然科学版)》1992,(4)

用模糊聚类方法,得出每种矿产的聚类中心,由此定义一个新的从属度,对预测单元进行模糊综合评判。该方法基本解决了预测单元多,已知条件少的成矿预测问题。  相似文献   

深Ⅱ°烧伤创面应用CHIMEHERB人工皮与酒精冷藏猪皮的比较     

刘久春  祁锋 《中国海洋大学学报(自然科学版)》1989,(Z3)

通过CHIMEHERB人工皮与酒精冷藏猪皮在深Ⅱ°及混合度烧伤创面上的应用比较,表明两者的粘附,透水等性能以及止痛效果一致.且前者比后者的优点是:不占位、平均提早创面愈合时间2～3.5d(天),并减少换药次数.  相似文献   

昆明市泥石流风险性评价研究   总被引：1，自引：1，他引：0  

张绪教  刘光旭  吴文祥 《地质灾害与环境保护》2008,19(2):79-85

采用比较成熟的泥石流危险性评价模型,结合ESRI（Environment System Research Institute）公司开发的新一代GIS软件——ARCGIS9．2,对昆明市泥石流进行危险度评价,得出了昆明市各县区的危险度。易损性评价是泥石流灾害风险性评价的一部分,根据国内有关易损性的理论成果,我们建立了昆明市泥石流易损性评价模型,对昆明市以各县区为单位进行了易损性评价,得出了昆明市各县区的易损度。利用联合国给出的自然灾害风险性评价模型：R—H×V,易损度和危险度相乘,得出了昆明市的风险度。使用ARCGIS9．2的自然分级和制图输出功能,对昆明市泥石流风险性进行了分区和制图,给出了昆明市泥石流风险性评价图。结合实际情况综合评判之后发现昆明市各县区呈现出泥石流灾害易损度和危险度不均衡的现象,因此,泥石流灾害发生时,外部社会救援工作就显得特别重要。  相似文献   

后压浆旋挖钻孔灌注桩单桩竖向承载力分析   总被引：1，自引：0，他引：1  

梁金国 《岩土工程技术》2008,22(3):139-144

通过后压浆旋挖钻孔灌注桩现场测试结果,分析了后压浆旋挖钻孔灌注桩的承载力、桩身荷载传递规律、桩的极限侧阻力分布规律。桩在竖向荷载作用下,桩的极限侧阻力发挥度,随桩的入土深度而衰减。提出了侧摩阻发挥度分布表达式及后压浆旋挖钻孔灌注桩单桩承载力计算方法,计算结果与试验结果较为符合。为后压浆旋挖钻孔灌注桩的设计提供了理论依据。  相似文献