运用静力触探技术探求水坠坝流态区位置的研究——以陕西省志丹县前拐沟淤地坝为例

水坠法修筑淤地坝技术近年来得到了广泛的应用和推广,但流态区的存在使得该技术具有一定的安全隐患,对于流态区位置的探求,常规的土钻法费时费力。以陕西省志丹县前拐沟淤地坝为研究对象,运用静力触探技术,结合SURFER软件作图探求流态区位置,并验证坝体稳定性。采用该方法探求水坠坝流态区位置,具有操作简单、快速精确的特点。

外加应力场刺激下固体“类流态”胞区的响应特征

介绍了在外加应力场刺激下固体“类流态”的响应特征。通过对几组CuZnAl合金试样进行压力实验和显微硬度测定 ,发现固体“类流态”胞区在应力场刺激下可以被诱发 ,而且试样上所施加的诱发应力在不同的尺度有明显的自相似性 ,这一点从其显微硬度的测定中能很好的反映。说明“类流态”胞区受应力场刺激时可以被诱发 ,而且诱发条件在宏观尺度上具有分形特征。

给水厂高密度沉淀池沉淀区流态模拟及优化设计

以重庆市某拟建大型给水厂的高密度沉淀池设计为原型,利用FLUENT软件中的固液两相流模型和标准k-ε两方程湍流模型,对其沉淀区内的流态进行数值模拟。模拟结果表明,其沉淀区内存在较为严重的短流、异重流及漩涡现象。为此进一步探讨了沉淀区内流态的改进方法,提出了通过提高进水流速来消除异重流以及优化配水区结构和集水方式来改善斜板区流态等措施。

水泵水轮机水泵工况顶盖下腔特殊压力脉动模型试验研究

随着抽水蓄能电站建设的加速推进,高水头、大容量的抽水蓄能机组逐渐成为发展主流。部分高水头大容量抽水蓄能机组在水泵工况运行时,监测到顶盖下腔出现特殊频率的压力脉动现象,引起了业内的广泛关注。为了深入揭示该现象的产生机理,通过设置干扰物的方法,改变流道中的流态,开展顶盖下腔特殊频率模型试验研究。试验结果表明:通过对无叶区流态的干扰,顶盖下腔与无叶区压力脉动发生变化,特殊频率幅值与区域被减弱,水泵工况顶盖下腔出现的特殊频率压力脉动现象主要受无叶区流态影响,而受顶盖下腔体流场影响较小。

振冲密实处理细砂、粉砂的发展

基于细砂、粉砂振冲密实的性能,通常在振冲的同时都要向振冲孔内,外加粗粒填料。近几年发展了不外加填料振冲,亦可取得良好的密实效果,并首次成功地应用于洋山深水港港区大面积粉砂、细砂冲填场地的处理。本文通过粉、细砂的性态分析了阻碍其采用无填料振冲密实的原因和相应的改进措施。

广洋湖、兰亭荡退圩还湖实施方案效果浅析

广洋湖、兰亭荡位于里下河宝应县境内,现状主要以圩区的形式存在,并不具备湖泊功能,随着经济发展,宝应县提出了退圩还湖的需求。介绍了广洋湖、兰亭荡退圩还湖实施方案,并对退圩还湖实施后湖荡的防洪除涝效果、供水效果以及湖区流态变化情况进行了分析。

Turbulence regime near the forest floor of a mixed broad leaved/Korean pine forest in Changbai Mountains

The measurement and observation for this study were carried out by using a three-dimensional (u, v, w) Sonic anemometer (IAP-SA 485), at Forest Ecosystem Opened Research Station of Changbai Mountains (12828扙 and 4224?N, Jilin Province, P. R. China) in August 2001. The basic characteristics of turbulence, such as turbulence intensity, atmospheric stability, time scales, and convection state, near the forest floor were analyzed. It is concluded that the airflow near forest floor is characterized by high intermittence and asymmetry, and the active and upward movement takes the leading position. Near forest floor, the vertical turbulence is retained and its time scale and length scale are much less than that of u, v components. The eddy near forest floor shows a flat structure and look like a ’Disk’. Buoyancy plays a leading role in the generation and maintenance of local turbulence

Nitrate Nitrogen Content Characteristics in Groundwater of Typical Planting Areas in Liao River Basin

The contents of nitrate nitrogen（NO-3-N） in underground water from typical planting areas in Liao river basin were analyzed, so as to provide theoretical basis for rational fertilization and effectively prevent the NO-3-N content from exceeding standard. The results showed that difference of the contents of NO-3-N in groundwater from different typical planting areas was significant. The highest content of NO-3-N in underground water was 37.4 mg/L from flower-growing region, then 22. 3 mg/L from maize-growing region, 21.9 mg/L from vegetable-growing region, and the lowest content of NO-3-N in underground water was 19.2 mg/L from rice-growing region. Except rice-growing region, the contents of NO-3-N in underground water of the samples in all planting areas were exceeding standard limit; potential health risk still existed in rice-growing region. Accordingly 12.5%-87.5%, 9.4%-75.5%, 17.9%-58.9% and 21.4%-96.0% of the samples were exceeding standard limit in maize growing region, rice-growing region, vegetable-growing region and flower-growing region. The contents of NO-3-N in under-groundwater before the rainy season was higher than that of NO-3-N in under-groundwater after the rainy season at the same depth of the well.

Research of Ecological Restoration of Jari Agricultural Demonstration Site in Ethiopia

In order to resolve the issue of soil erosion in East African plateau, a micro-landscape irrigation region was established in Ethiopia plateau to research status quo of agricultural demonstration site in Jari in Ethiopia and to analyze the relation between structure and function of inner elements in different landscapes of demonstration site. Furthermore, in accordance with ecology, silviculture, agriculture and economics, the ecological landscapes were classified as per landscape functions; lands returning from farming were classified and re-used; ecosystems of grassland, river, agriculture and courtyard were researched; the feasibility of ecological restoration and sustainable development in demonstration site was demonstrated; the model for rational irrigation and water conservation was proposed. The research guarantees sustainable development of agriculture and animal husbandry and provides references for undeveloped countries with similar problems.

Effects of a flexible net barrier on the dynamic behaviours and interception of debris flows in mountainous areas

Flexible net barriers are a new type of effective mitigation measure against debris flows in valleys and can affect the kinematic energy and mass of debris flows. Here, ten flume tests were performed to study the dynamic behaviours of debris flows with differences in volumes, concentrations(solid volume fraction), and travel distances after interception by a uniform flexible net barrier. A high-speed camera was used to monitor the whole test process, and their dynamic behaviours were recorded. A preliminary computational framework on energy conversion is proposed according to the deposition mechanisms and outflow of debris flow under the effects of the flexible net barrier. The experimental results show that the dynamic interaction process between a debris flow and the flexible net barrier can be divided into two stages:(a) the two-phase impact of the leading edge of the debris flow with the net and(b) collision and friction between the body of the debris flow and intercepted debris material. The approach velocity of a debris flow decreases sharply(a maximum of 63%) after the interception by the net barrier, and the mass ratio of the debris material being intercepted and the kinetic energy ratio of the debris material being absorbed by the net barrier are close due to the limited interception efficiency of the flexible net barrier, which is believed to be related to the flexibility. The energy ratio of outflow is relative small despite the large permeability of the flexible net barrier.

Gaseous Loss of Nitrogen from Fertilizers Applied to Wheat on a Calcareous Soil in North China Plain

Nitrogen (N) losses from ammonium bicarbonate or urea applied to wheat and then followed immediately by irrigation were investigated. Ammonia volatilization was determined by a micrometeorological method (ammonia sampler), total N loss was estimated by the 15N mass balance method, and denitrification loss was measured by the difference method (calculated from the difference between the total N loss and ammonia loss)and a direct method (measuring the emission of (N2+N2O)-15N ). Total ammonia losses from ammonium bicarbonate and urea in 33 days were 8.7% and 0.9% of the applied nitrogen, respectively. The corresponding total N losses were 21.6% and 29.5%. Apparent denitrification losses (by the difference method) were rather high, being 12.9% from ammonium bicarbonate and 28.6% from urea. However, no emission of (N2+N2O)-15N was detected using the direct method.

Characteristics and Effects of Inorganic Nitrogen in East Water-source and Inflow Rivers of Chaohu Lake

[Objective] To study the characteristics and effects of inorganic nitrogen in east water-source and inflow rivers of Chaohu Lake. [Method] The speciation and distribution characteristics of dissolvable inorganic nitrogen （DIN） in east water-source and inflow rivers of Chaohu Lake were investigated, and their effects on water qual- ity were examined. [Result] The concentrations of NH3-N and NO2--N were the high in flood season, and low in non-flood season, while the concentration of NO3--N pre- sented the opposite trend; the concentration of NO3--N was the highest in Shuangqiao estuary, where the pollution was the worst. DIN in Zhegao estuary and Xiaozhegao estuary was mainly caused by domestic sewage and industrial wastewaters; surface runoff and pollution from ships contribute the most to the DIN content in Shuangqiao estuary. [Conclusion] This study provided basic data and theoretical basis for the control and management of eutrophication in Chaohu Lake.

Two-Bubble Class Model for Churn-Turbulent Regime in a Bubble Column Slurry Reactor of Fischer-Tropsch Synthesis

A model for a bubble column slurry reactor is developed based on the experiment of Rhenpreussen Koppers demonstration plant for slurry phase Fischer-Tropsch synthesis reported by Koelble et al. This model is applicable to the operation in the churn-turbulent regime and incorporates the information on the bubble size. The axial dispersion model is adopted to describe the flow characteristics of the Fischer-Tropsch slurry reactor. With the model developed, simulations are performed to identify the steady state behavior of a Fischer-Tropsch slurry reactor of commercial size. Predictions of the two-bubble class model is compared with that of the conventional single- bubble class model. The results show that under a variety of conditions, the two-bubble class model gives results different from those for the single-bubble class model.

Research on Water Resources Conservation of Mountain River Based on the Concept of Region Partition

Presently concepts and methods related to water resources conservation of mountain rivers are seriously insufficient,and its level is far from being adaptable to the development of a harmonious society.As mountain ecosystems play a key role in water resources conservation of mountain rivers,and the characteristics of mountain ecosystems and hydrologic features of mountain river follow strong temporal and spatial distribution,partition theory can be applied to the water resources conservation of mountain river.This theory observes the following partition principles:regional relativity,spatial continuity,integralcounty,meeting management needs,hierarchical principle,and comparability principle.And it lays equal emphasis on both water resources conservation and environmental protection,on both water quality conservation and water quantity protection,on the combination of water features,water cycle and water pollution.In the partition methods,index method and map superposition method will be applied in region partition.The example of region partition of water resources conservation in the upper reaches of the Yangtze River shows that the partition theory is practicable in water resources conservation of mountain rivers,and it provides a platform for future study in water resources conservation.

Methodological Framework for a Multi-Scale Study on Hydrological Processes and Soil Erosion in Subtropical Southeast China

This paper introduces and illustrates the concepts of geoecological process combinations and geographical or landscape dimensions by outlining the methodology of a Sino-German cooperative project in Southeast China and presents the first results of the modelling process for the catchment scale. The project equipped a catchment in subtropical Southeast China from plot scale to catchment scale in order to study the hydrological and soll erosion processes. Distinct spatial differences in principal water and soil material fluxes were quantified. Deep drainage peaks occurred in May, June and July and even in August and November. Measurements in erosion plots as well as sedimentary deposits revealed that there was soil erosion connected with overland flow. Consistent with the results from the regular catenary variations of soil colors, textural stratification and hydrograph analysis, there was also a clear indication of interflow from measured soil moisture data. The experimental set up has the potential to further deepen the understanding of small-scale processes involved in lateral water fluxes and soil erosion. The expected results and interpretations will lead to a further integration of the collected data. In the future, to understand matter transfer in and between landscape ecological units, agricultural influence on nutrient status and flux data will be incorporated.

GIS-based Effect Assessment of Soil Erosion Before and After Gully Land Consolidation: A Case Study of Wangjiagou Project Region, Loess Plateau

The Loess Plateau is one typical area of serious soil erosion in the world. China has implemented ′Grain for Green′(GFG) project to restore the eco-environment of the Loess Plateau since 1999. With the GFG project subsidy approaching the end, it is concerned that farmers of fewer subsidies may reclaim land again. Thus, ′Gully Land Consolidation Project′(GLCP) was initiated in 2010. The core of the GLCP was to create more land suitable for farming in gullies so as to reduce land reclamation on the slopes which are ecological vulnerable areas. This paper aims to assess the effect of the GLCP on soil erosion problems by studying Wangjiagou project region located in the central part of Anzi valley in the middle of the Loess Plateau, mainly using the revised universal soil loss equation(RUSLE) based on GIS. The findings show that the GLCP can help to reduce soil shipment by 9.87% and it creates more terraces and river-nearby land suitable for farming which account for 27.41% of the whole study area. Thus, it is feasible to implement the GLCP in places below gradient 15°, though the GLCP also intensifies soil erosion in certain places such as field ridge, village land, floodplain, natural grassland, and shrub land. In short, the GLCP develops new generation dam land and balances the short-term and long-term interests to ease the conflicts between economic development and environmental protection. Furthermore, the GLCP and the GFG could also be combined preferably. On the one hand, the GFG improves the ecological environment, which could offer certain safety to the GLCP, on the other hand, the GLCP creates more farmland favorable for farming in gullies instead of land reclamation on the slopes, which could indirectly protect the GFG project.

Ecosystem health evaluation system of the water-fluctuating zone in the Three Gorges Area

This paper discribes the definition of ecosystem health for the water-level flutuation zone of the Three Gorges Region and puts forward an evaluation system involving indicators in three groups: 1) structural indicators comprise slope, biodiversity, environmental capacity, stability, restoration ability and damage situation; 2) functional indicators including probability of geological hazard, erosion rate, habitat rate, land use intension and days of tourist season; 3) environmental indicatiors made up of population quality, potential intension of human, ground water quality, ambient air quality, wastewater treatment rate, pesticide use rate, fertilizer use rate, environmental management and public participation. In the design of the system, the subject zone is regarded as the type similar to wetland and the impacts of human activities on the zone are attached great importance to.

Assessment of Soil Erosion in Mountain Watershed Ecosystems in Tirana-Region

Land erosion is an increasing problem that is seriously affecting our country in recent years. In many areas of our country, mountainous and hilly territories suffer major erosion in both surface and depth, where the solids are deposited in the flat parts of the country, thus leading to a higher content of gravel in agricultural land and filling of the sewage networks. The phenomenon of erosion is greater in the vicinity of residential areas where damages are larger and more sensitive. One of the most vulnerable in our country in terms of soil erosion is the district of Tirana. This study had the main goal to define and categorise of erosion rates in natural environments of the forest economies of the Tirana, the rate of recovery of vegetation, slope and rainfall index, which will serve as information and guidance on the land use by farmers, communes and the state regulatory officials, depending on the ownership of these woodland surfaces.

Soil Erosion Changes over the Past Five Decades in the Red Soil Region of Southern China

This paper reports the dynamic changes of soil and water loss in the red soil region of Southern China since the 1950s. The red soil region covers eight provinces: Jiangxi, Zhejiang, Fujian, Anhui, Hubei, Hunan, Guangdong and Hainan. From the 1950s to 1986, the annual rate of soil erosion increased by 3.4%. From 1986 to 1996 and from 1996 to 2000, the annual rates of soil erosion decreased by 2.0% and 0.32%, respectively. Field surveys showed that from 2000 to 2005, the area of soil and water loss decreased annually by 1.2%. This decrease was a result of large-scale erosion control activities across China. Although the eroded soil has been restored, the restoration process is very slow and full restoration will take a long time. Our report suggests that controlling soil and water loss is a challenging task, and additional measures must be taken to effectively control the soil erosion in the red soil region.

Influence analysis of flow rule in mine fire during injecting inert gases

According to the action law of gas flow during injecting inert gases as the research main line, and hydromechanics and thermodynamics theories, the characteristic of gas delamination that was caused by injecting inert gases to closed fire zone was analyzed. The criterion was brought forward, which could scale disappearing probability of turbulent state. Formation mechanism of gas layer in turbulent state was discussed primarily. Simultaneously, the condition was pointed out, which could makc the gas in turbulent state by injecting different gases. The mathematical model about dynamic changes of oxygen and methane concentration in the process of injecting gases was erected. The mixture mechanism about injecting different flow inert gases and flammable gas layer in closed fire zone was revealed.