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1.
Peculiarities of the tungsten deposits drainage flow chemical composition formation, the development of which was ceased almost 40 years ago, have been considered. Migration peculiarities of ore components have been covered, and forms of their migration have been calculated. Inertial characteristics of the surface flow contamination are shown.  相似文献   

2.
概略地叙述了西宁地区的泥石流形成条件和形成机理,并将西宁地区泥石流划分为稀性泥石流类及泥石质泥石流种类。在此基础上提出防治泥石流灾害的意见。  相似文献   

3.
栖霞市生木树泥石流隐患点为烟台市471处地质灾害隐患点其中1处,曾于1979年7月因暴雨引发泥石流灾害,给当地村民造成严重经济损失。以该泥石流沟流域作为研究区,并以区内泥石流发育的自然环境、基本特征及形成泥石流的地质条件、物源条件和水源条件等勘察成果为基础,综合分析区内泥石流发育特征、类型、形成机理、引发因素,并选取相关参数对泥石流基本特征值进行计算,为同类型泥石流的防治提供科学依据。综合研究确定区内泥石流易发程度为轻度易发,现阶段泥石流沟发展阶段为发展期,泥石流灾害趋于相对稳定,但一旦遭遇暴雨至特大暴雨,可能会再次引发泥石流地质灾害。  相似文献   

4.
应用给定换热器结构材料而使换热量最大的两侧换热表面的最佳匹配准则和使可用能损失率最小的最佳运行参数准则。利用两个准则间的关系 ,采用迭代的方式完成换热器的优化设计 ,使换热器的设计达到材料省、换热效果好及运行费用低的目的 ,且能在设计阶段实现。  相似文献   

5.
山东省威海市滨海新城作为威海市的新行政中心,是威海市着力打造的宜居、宜业、宜游、宜学的现代化卓越新城。本文采用MIKE21FM平面二维数值模型研究威海市滨海新城北部海域的潮流场运动,并以分层流速流向实测资料对模型进行验证。结果表明,研究区潮流场流速和流向数值模拟结果与实测资料变化基本一致。  相似文献   

6.
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7.
针对现有公共地理框架数据更新作业过程中存在的流程不畅、进度难以把控等问题,简要介绍了工作流即工作流管理系统的参考模型,并将工作流技术引入公共地理框架数据的更新作业流程中,实现更新作业过程中流程的自动扭转,减少流程的闲置时间,增强项目管理控制的能力。  相似文献   

8.
程裕淇确定了泰山岩群雁翎关组、山草峪组、柳杭组地层划分,在斜长角闪岩中发现残存的变余杏仁状构造和岩流特征,正确区分了变基性熔岩流、变火山凝灰质岩和变基性脉体。原化马湾组黑云斜长片麻岩为新太古代早期条带状英云闪长质片麻岩。富山背斜的片麻状奥长花岗岩锆石SHRIMP U-Pb年龄(2 612±20)Ma,其侵入的具变余气孔状充填构造的斜长角闪岩属于雁翎关组;而李家庄倒转向斜核部的柳杭组含砾黑云变粒岩中最年轻的碎屑锆石SHRIMP U-Pb年龄(2524±7)Ma。  相似文献   

9.
Taiwan has disadvantageous conditions for sediment-related disasters such as debris flows. The construction of engineering structures is an effective strategy for reducing debris flow disasters. However, it is impossible to construct engineering structures in all debris flow areas in a short period. Therefore, the government aims to gradually develop non-structural preventive strategies, including evacuation planning, debris flow disaster emergency action system, disaster resistant community program, recruitment of debris flow professional volunteers, debris flow warning systems, and land management strategies, to mitigate disasters and secure the safety of residents. This review describes the processes and effects of recent debris flow non-structural preventive strategies in Taiwan. The average number of casualties prior to the year 2000 was far higher than the corresponding number after 2000 because debris flow evacuation drills have been promoted since 2000 and the debris flow disaster emergency action system has been progressively improved since 2002. Furthermore, the changes in risks caused by debris flow disasters before and after the implementation of non-structural preventive strategies were used to explain the effectiveness of these strategies at the community level. The results showed that software-based non-structural preventive strategies can effectively reduce the casualties caused by debris flows at both the national and community levels.  相似文献   

10.
全面分析研究区玄武岩潜水含水层水文地质条件的基础上,对稳定流和非稳定理论确定潜水含水层渗透系数的优缺点进行了对比,认为非稳定井流公式确定玄武岩潜水含水层渗透系数是合理的。Aquifer Test软件基于Neuman井流理论配线法求参原理,运用计算机完成了自动求参,避免了人工配线的不足。该文根据吉林靖宇煤矿研究区玄武岩潜水含水层非稳定流抽水试验,分别用Aquifer Test软件和稳定井流公式进行了求参,并对比分析得出:玄武岩含水层弹性释水作用影响时间较长,利用Neuman潜水井流公式求参可靠,且更逼近现实;用Aquifer Test软件实现了自动求参,具有操作简单规范、可比性好的优点。  相似文献   

11.
地下水年龄和滞留时间包含了地下水循环和演化的重要信息,被广泛用于盆地地下水循环模式的研究。使用多级次地下水流系统演示仪,实验模拟了三级水流系统模式中地下水年龄及滞留时间分布。研究发现,盆地底部、区域流线的下游、盆地滞留区最晚响应;浅部的局部水流系统稳定后的浓度值相对较低;中间水流系统相对深部的区域水流系统也较低,滞留区盐分积累,浓度值相对较大。盆地内部所有监测点的地下水年龄分布曲线都为单峰,区域水流系统的循环时间大于中间水流系统以及局部水流系统。在排泄区监测的滞留时间分布显示不同级次补给会产生早、中、晚峰,并且峰值与地下水流系统的级次性完全对应,可以通过排泄区的峰值判断地下水是从局部、中间或区域水流系统补给而来,以此判断污染物的来源。本研究成果对于地下水的循环演化和地下水流系统理论的完善具有一定的意义。   相似文献   

12.
Debris flows are among the most common geological disasters in China,and have been particularly frequent in Sichuan Province since the Wenchuan earthquake on 12 May 2008.The construction of debris flow drainage channels is a countermeasure used to distribute debris flow fans,and these channels play a critical role in the mitigation and prevention of damage resulting from debris flows.Under field conditions,the useful life of drainage channels can be greatly shortened as a result of strong abrasions to the drainage structure caused by the debris flow.Field investigations have shown that the types of damage to drainage channels include(a) erosion caused by hyper-concentrated silt flow,(b) impact fractures and foundation scour at the groundsills of the drainage channel,(c) destruction of the drainage channel outlet,and(d) destruction of the drainage channel caused by debris flow abrasion.In addition,based on the destruction of the drainage channel during the debris flow drainage process,a new type of drainage channel with energy dissipation components was proposed and applied in a steep,narrow gully for debris flow mitigation.Moreover,design and engineering repair recommendations for drainage channels are provided as a reference for repairing the damage to the channel.The results can provide an important reference for the effective repair and optimal design of drainage channels.  相似文献   

13.
近20多年,济南泉水流量逐渐衰竭,泉水断流时有发生,为保护泉水,恢复泉水喷涌,塑造济南城市形象,该次研究基于50多年的济南地下水勘查、试验和研究成果,实现对城市多源、海量、多期次、多比例尺、异构地质数据的有效管理,然后建立不同地质数据的专业模型,实现对模型时空展布特征的三维可视化再现,并提供对模型的专业处理与分析。最后,从二维三维等水文地质概念模型出发,加入时间维度,由历史积累的时空关系,反映济南城市地下水的时空变化规律,在三维地质模型的基础上实现地下水动态监测数据的嵌入,构成地下水四维地质信息系统,在其空间表征的基础上,介绍了城市地下水的形成,泉水的分布、成因、演化以及泉水断流的原因、保泉供水的对策措施等,引导城市地下水的保护和发展,为政府决策提供参考。  相似文献   

14.
Debris flow is one of the most destructive phenomena of natural hazards. Recently, major natural haz-ard, claiming human lives and assets, is due to debris flow in the world. Several practical methods for forecasting de-bris flow have been proposed, however, the accuracy of these methods is not high enough for practical use because of the stochastic and non-linear characteristics of debris flow. Artificial neural network has proven to be feasible and use-fill in developing models for nonlinear systems. On the other hand, predicting the future behavior based on a time se-ries of collected historical data is also an important tool in many scientific applications. In this study we present a three-layer feed-forward neural network model to forecast surge of debris flow according to the time series data collect-ed in the Jiangjia Ravine, situated in north part of Yunnan Province of China. The simulation and prediction of debris flow using the proposed approach shows this model is feasible, however, further studies are needed.  相似文献   

15.
1Introduction GamakBay,anegg shapedseasurfaceareaofap proximately112km2,isasemi enclosedshallowwaterareawithameandepthof9mandhasbotheastandsouthchannelstoreceiveseawaterfromoutside(seeFig.1).Similarscalesoftidalwavesalmostsimultane ouslyenterorexitthrough…  相似文献   

16.
Techniques of gully-specific debris flow hazard assessment developed in four periods since the end of the1980s have been discussed in the present paper. The improvement for the empirical assessment method is the sectional-ized function transformation for the factor value, rather than the classified logical transformation. The theoretical equationof the gully-specific debris flow hazard is expressed as the definite integral of an exponential function and its numericalsolution is expressed by the Poisson Limit Equation. Current methods for assessment of debris flow hazard in China arestill valid and practical. The further work should be put on the study of the reliability (or uncertainty) of the techniques.For the future, we should give a high priority to the relationship between debris flow magnitude and its frequency of occur-rence, make more developments of prediction model on debris flow magnitude, so as to finally reach the goal of assessingthe hazard of debris flow by theoretical model, and realize both actuality assessment and prediction appraisal of debris flow.  相似文献   

17.
《山地科学学报》2020,17(1):156-172
Loose deposits, rainfall and topography are three key factors that triggering debris flows.However, few studies have investigated the effects of loose deposits on the whole debris flow process.On June 28, 2012, a catastrophic debris flow occurred in the Aizi Valley, resulting in 40 deaths.The Aizi Valley is located in the Lower Jinsha River,southwestern Sichuan Province, China. The Aizi Valley debris flow has been selected as a case for addressing loose deposits effects on the whole debris flow process through remote sensing, field investigation and field experiments. Remote sensing interpretation and laboratory experiments were used to obtain the distribution and characteristics of the loose deposits, respectively. A field experiment was conducted to explore the mechanics of slope debris flows, and another field investigation was conducted to obtain the processes of debris flow formation, movement and amplification. The results showed that loose deposits preparation, slope debris flow initiation,gully debris flow confluence and valley debris flow amplification were dominated by the loose deposits.Antecedent droughts and earthquake activities may have increased the potential for loose soil sources in the Aizi Valley, which laid the foundation for debris flow formation. Slope debris flow initiated under rainfall, and the increase in the water content as well as the pore water pressure of the loose deposits were the key factors affecting slope failure. The nine gully debris flows converged in the valley, and the peak discharge was amplified 3.3 times due to a blockage and outburst caused by a large boulder. The results may help in predicting and assessing regional debris flows in dry-hot and seismic-prone areas based on loose deposits, especially considering large boulders.  相似文献   

18.
成武县位于鲁西南黄河冲积平原区,水系发达,地表水资源丰富。为了分析地表水系对成武县土地利用时空变化和空间格局的影响,该文基于不同时期的遥感影像,结合实地调查和专家意见,提取区域土地利用现状图;运用DEM地表水文分析提取河流汇流累积量、水流长度、河流网络等,根据流量选取了河网。以河流为中心向两侧作缓冲区,与土地利用现状图进行空间分析,得到不同距离缓冲区内的土地利用结构。与全区域土地利用结构对比,分析不同时期在相同的缓冲区域内土地利用特征和变化,总结土地结构变化规律,结合100m,200m,300m,400m,500m,750m,1000m不同的缓冲区;通过对比各种土地利用类型在不同距离缓冲区的时空变化,从而分析水系因子对不同土地类型时空变化的影响。结果表明,不同距离缓冲区内土地利用结构不同,随着缓冲区范围的增加,耕地、建设用地、林地、园地呈现不同的变化趋势与特点,水系因子对成武县不同土地利用方式影响程度不同,水系因素对成武县土地利用空间分异有明显影响。  相似文献   

19.
分析陆相断陷湖盆异重流沉积的识别特征、异重流水下扇沉积体系的横向、垂向沉积序列、以及不同物源碎屑成因的异重流的沉积差异性, 从而探讨陆相断陷湖盆中异重流沉积的控制因素。以歧口凹陷沙一下异重流沉积为研究对象, 对研究区钻井岩心、测录井、地震属性以及粒度分析资料进行综合分析。结果表明, 研究区异重流具有3种典型沉积识别特征: ①两类沉积序列, 分别为下部逆粒序、上部正粒序的纺锤状二元结构沉积序列以及厚度较大且粒度特征变化不明显的均一结构沉积序列; ②粒度分析特征以递变悬浮载荷为主, 累计概率曲线类型以复杂多段式、上拱曲线式、低斜率两段式为特征; ③岩相特征为侵蚀充填沉积、广泛发育且类型多样的层理构造, 其次为陆源褐红色泥质层、褐红色泥砾以及大量的植物茎干碎片和炭质碎屑。研究区异重流沉积接受多支物源供给表现出水道化特征, 葛沽物源为最主要物源, 总体具有长距离搬运、多个朵体发育、大范围沿路沉积等特征。建立了研究区扇三角洲和辫状河三角洲物源重力流沉积模式。断陷湖盆背景下异重流沉积的控制因素为古物源、古地貌、古气候3个方面, 异重流沉积是断陷湖盆中广泛发育的沉积类型, 其中异重流水道砂岩具有良好的储集物性, 是陆相断陷湖盆油气勘探的重要方向与突破点。   相似文献   

20.
In this study, the effects of length-width ratio and diversion trench of the spacer on the fluid flow behavior in an electrodialyzer have been investigated through CFD simulation method. The relevant information, including the pressure drop, velocity vector distribution and shear stress distribution, demonstrates the importance of optimized design of the spacer in an electrodialysis process. The results show width of the diversion trench has a great effect on the fluid flow compared with length. Increase of the diversion trench width could strength the fluid flow, but also increase the pressure drop. Secondly, the dead zone of the fluid flow decreases with increase of length-width ratio of the spacer, but the pressure drop increases with the increase of length-width ratio of the spacer. So the appropriate length-width ratio of the space should be moderate.  相似文献   

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