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1.
水利水电工程深基坑开挖时,必然会遇到地下水渗流问题,基坑排水将直接关系到工程能否顺利进行,基坑浸水后将影响到建筑物以后的安全,因此水利水电工程施工时,应重视基坑排水,应根据工程地质和水文地质情况确定适当的排水方案,并在基坑排水设计时应考虑到不利的情况。  相似文献   

2.
于飞 《给水排水》2005,31(10):112-114
介绍了《建筑排水系统吸气阀》产品标准的内容、意义,并对条款进行了分析和解释,特别指出吸气阀气密性试验前后压降10%,不是其泄漏值,而是确保其试验密封性的最低安全要求,也是进行重复试验时允许的最大偏差值的要求;认为制定了实验室测试方法和要求,可为吸气阀的使用提供可靠的保证,解决应用中的各种猜测和疑虑。介绍了吸气阀的应用。  相似文献   

3.
Brazil is currently facing widespread problems in the urban environment associated with inadequate wastewater and urban drainage systems, particularly for low-income communities. These problems are promoted by the rapid and often unplanned urbanization process in developing cities and are compounded by a lack of funding, absence of planning, ineffective institutional arrangements, and inappropriate policies to provide the framework for integrated wastewater and stormwater management. Because planning for the provision of wastewater and urban drainage systems is a complex task, an integrated-modeling approach is proposed to provide a practical methodology for sanitation and urban drainage planning in Brazilian cities. In the model development, as well as technical aspects, other aspects related to institutional, financial, socio-economic, environmental and public health issues were also taken into account.  相似文献   

4.
Self-cleansing is a substantial aspect of the drainage systems in which it is desired to minimize the sediment deposition that can cause channel blockage and surcharge early overflows. In the conventional self-cleansing design criteria of drainage systems, a single value of velocity or shear stress is used based on experience. In the recent decades rather than using a single value, non-deposition design concept has been further modified to develop self-cleansing models based on higher number of parameters considering flow, fluid, sediment and channel characteristics. However, non-deposition self-cleansing models have been mostly developed for circular channels, and none of the models considers yet the effect of channel cross-section although some models take into account the pipe diameter, hydraulic radius and cross-section area as independent variables. In this study, a self-cleansing model considering the effect of cross-section by a shape factor available in the literature is developed to determine the non-deposition particle Froude number for bed load sediment transport. The model is developed using experimental data of circular, rectangular and U-shape channel cross-sections from the literature; and data of trapezoidal channel cross-section from experiments carried out in this study. For validation of the model, data collected in this study is used together with four different sources of data taken from the literature. Validation of the model for each cross-section data shows its wide range applicability in terms of different channel cross-sections.  相似文献   

5.
One of the main concerns associated with the recycling of biosolids to arable land is their contamination by organic pollutants, like endocrine disruptors. Conditioning and dewatering are usually the last steps of the sewage sludge treatment, before its further utilization. The choice of the specific conditioning/dewatering method may have an effect, not only on the amount of residues in the biosolids, but also on the fate of these compounds in amended soils. Anaerobically digested wastewater sludge was conditioned at lab-scale by means of physical and chemical methods and subsequently dewatered by centrifugation. The produced biosolids plus non-conditioned and non-dewatered sludges were amended separately to soil and spiked with 14C radiolabelled single isomer of nonylphenol. The persistence and leaching potential of nonylphenol after an incubation period of three months were correlated to the sludge treatment method. In comparison to non-conditioned sludge, 54% and 72% higher amount of pollutant residues were extractable when freeze-thawed and limed sludge, respectively, were used. Conditioning of sludge with cationic polymer decreased the leaching potential of nonylphenol in sludge-amended soils, while liming increased it. Fractions of the model compound recovered as extractable and bound residues were analyzed in order to interpret nonylphenol fate.  相似文献   

6.
上海市排水小区地下水渗入量研究   总被引:8,自引:0,他引:8  
介绍了排水小区地下水渗入量测试的基本方法。采用夜间最小流量法和用水量折算法 ,对上海市代表性排水小区地下水渗入量进行了实测和分析 ,确定了不同类型排水小区的渗入量范围。对区域渗入量试验中需要关注的问题进行了研讨。研究成果为推动渗入量研究、改进高地下水位地区排水系统的设计、维护与管理提供了依据  相似文献   

7.
结合不同的大屋面材料、形状 ,介绍了长天沟外排水、重力流悬吊管、敞开系统内埋地管式、封闭系统内埋地管式及压力流 (虹吸式 )屋面雨水系统的特点及适用性。另外对轻钢结构厂房雨水系统设计应注意的一些问题作了说明  相似文献   

8.
Implementing control structures such as gates at suitable locations in the urban drainage network enables its improved utility by actively controlling and optimizing the flow during a flood event. The successful operation of the control structure is fully governed by the suitability and efficiency of the control strategy adopted, which in turn depends on the response characteristics of the urban drainage system under different flow conditions. For an extreme rainfall event, it is necessary to model the transient flow in the urban drainage system. However, such an exercise is mostly restricted by the limited data and lack of in-depth survey of urban drainage systems in most of the developing countries like India. Taking this into consideration, an alternate approach has been presented in this paper for modeling the transient flow in the urban drainage system under limited data availability. The results obtained have also been compared with the finite difference model using four-point implicit scheme in time domain. The developed model can be used for the computation of temporal distribution of water surface profile with special consideration of lateral inflow. The application has been demonstrated by applying it to a representative catchment in Mumbai, India.  相似文献   

9.
针对以黄河水为原水的给水厂污泥进行了混凝及优选比阻调理试验,结果表明:当进行给水厂污泥脱水技术改造方案设计时,可以不经过混凝处理,直接利用电厂粉煤灰作为比阻调理剂。细粉煤灰的最佳投加率为20%,粗粉煤灰的最佳投加率为30%,使污泥比阻由1013数量级降至1010数量级,改善了污泥脱水性能,所得滤饼含水率仅为40%~50%,易于剥离,能耗低,所得滤液的色度、浊度、CODMn均达到可直接回用标准。当进行技改工程设计时,建议选用带式压滤机或板框压滤机,既适应粉煤灰调理剂,又可节约投资。  相似文献   

10.
Performance indicators implemented in a decision support system (DSS) for the technical, managerial and economic evaluation of urban drainage systems (UDS), called MOMA FD, are presented. Several kinds of information are collected and processed by MOMA FD to evaluate both present situation and future scenarios of development and enhancement. Particular interest is focused on the evaluation of the environmental impact, which is considered a very relevant factor in the decision making process to identify the priorities for UDS improvements.  相似文献   

11.
本文在分析现有城市雨洪排放系统的脆弱性的基础上,结合分布式水文模型应用于雨洪排放系统设计的优势,提出了基于分布式水文模型的城市雨洪排放优化设计的思路,并给出了系统优化的若干建议。  相似文献   

12.
为了探究涵闸进口水位—流量关系未知且外江潮水对内江洪水具有顶托作用的调洪演算过程,在传统的列表试算方法基础上提出了单时段内根据涵闸运行原则且基于拉格朗日n次插值多项式的泄流前及泄流后容积水深插值调洪算法,为了计算方便,采用C++编写拉格朗日插值程序。将改进算法的计算结果代入传统的列表试算法中进行验证,计算结果表明只有个别时段水深值具有微小偏差,改进后的算法具有较高的精度。改进后的算法不仅可以避免传统算法的大量试算,为传统算法提供准确的试算初始点,而且对于类似实际工程的调洪演算具有一定的参考价值。  相似文献   

13.
《Journal of Hydro》2014,8(4):330-342
Despite remarkable advances in urban flood management techniques, pluvial flood damages still occur throughout the world. This may be attributed to uncertainties in the rainfall events which may disrupt the normal performance of an urban drainage system and eventually lead to inundations and damages. Therefore, the conventional urban drainage management approach focusing on system security should be modified. As a new approach to urban drainage management, this paper defines the persistence of a system as the ability of a disturbed system to resist, buffer the effects of variable disturbances and return to accepted level of performance after disturbances and introduces a framework to evaluate the concept of risk management persistence for urban drainage systems based on joint consideration of resilience and resistance standpoints. Based on this perspective, some of the required indicators were selected from the literature and adapted to the present study in order to quantify urban drainage risk management (UDRM) systems persistence against disturbances. Evaluation of urban drainage measures would indicate the level of persistence achieved. As a case study, part of the urban drainage system of city of Tehran–Iran was analyzed using the proposed scheme. Four urban drainage measures including three best management practices (BMPs) and a conventional system were added to the current urban drainage system to assess the performance of various measures in improvement of the persistence of UDRM systems. Results indicate that the analysis of the systems persistence can efficiently enable urban planners to select measures with an insight into the behavior of the UDRM systems faced with disturbances.  相似文献   

14.
In drainage of agricultural lands, the upward vertical recharge from a semi-confined aquifer depends on the difference of the piezometric heads on the two sides of the semi-impermeable layer through which this recharge takes place. This means that the recharge through the semi-impermeable base depends on the unknown height of the unsteady water table. In the nonhomogeneous Boussinesq equation, which describes the drainage problems, the downward uniform rate of the recharge from rain or irrigation and the recharge from the semiconfined aquifer are expressed by two terms. By solving the Boussinesq equation expressions for the nondimensional height of the water table and the nondimensional discharge of the drains per unit drained area are obtained for three different initial conditions. Some known solutions are shown as special cases of the present solutions. Variation of nondimensional water table heights at half distance of the drain spacing and the nondimensional discharge of the drains with nondimensional time have been graphically illustrated with the help of synthetic examples.Notation B s thickness of the semi-impervious layer [L] - c hydraulic resistance of the semi-impervious layer [T] - D depth of the drains from the base [L] - d e equivalent depth [L] - h=h(x, t) height of the water table [L] - h 0 initial height of the water table [L] - h t water table height at mid-distance of drains att [L] - h j ,h k water table height at mid-distance of drains at timej andfk, respectively [L] - H 0 piezometric head in the semi-confined aquifer [L] - K hydraulic conductivity of the soil [LT–1] - K s hydraulic conductivity of the semi-impervious layer [LT–1] - k 0,k 1,k 2 nondimensional constants - L distance between the drains [L] - q 0 upward recharge per unit surface area through the semi-impervious layer [LT–1] - q t discharge per unit drainable area of drains at timet [LT–1] - R,R 0 recharge per unit surface area from rain or irrigation during the unsteady and steady-state, respectively, [LT–1] - S specific yield of the soil - t time of observation [T] - x distance measured from the drain [L] - leakage factor [L] - nondimensional distance - nondimensional time  相似文献   

15.
16.
介绍了欧洲水环境系统计算机模型软件公共接口--OpenMI 技术的工作原理,就其对水环境系统模型的作用与意义进行了阐述.列举了OpenMI技术在国外实际建模工程中的应用.构建了基于OpenMI 技术的我国城市排水模型架构体系.最后简述了该技术对我国水环境系统计算机建模工作者的启发.  相似文献   

17.
污泥浓缩脱水投药量优化控制的研究   总被引:7,自引:0,他引:7  
城市污水处理厂污泥浓缩脱水的药剂消耗是主要的运行费用。通过北京市高碑店污水 处理厂连续两个月的试验,考察了污泥浓缩脱水最佳投配比与污泥浓度之间的关系并建立了优化控 制模型。用该模型进行了一个月的试生产,结果表明,对加药量进行优化控制相对于人工控制不仅 保证了处理效果,同时也有效地降低了运行费用。  相似文献   

18.
海平面上升将影响浙江海岸带的水环境,抬高沿海潮水位和滨海平原水位,不利于沿海城镇和农田排涝,通过对沿海排涝的影响分析,提出了相应对策.  相似文献   

19.
深基坑降水与地面沉降变形三维全耦合模型及其数值模拟   总被引:2,自引:2,他引:2  
针对第四纪松散沉积层地区深基坑降水引起的地面沉降问题,以比奥固结理论为基础,并将其推广应用于非线性问题。考虑到土的渗透性随应力状态的动态变化,将地下水渗流场和土体应力场相耦合,建立水土全耦合模型,并以上海市环球金融中心深基坑降水为例,采用三维有限元数值分析方法,详细模拟分析了降水引起的基坑内外地下水位和地面沉降变形的变化特征,据此获得的基坑中心水位降至-22m时基坑周围的地下水位与地面沉降变形量,经后续工程验证正确、可靠,该模型具有重要的工程实用价值。  相似文献   

20.
苏州河沿岸排水系统雨水调蓄池设计方案探讨   总被引:1,自引:0,他引:1  
探讨了通过式雨水调蓄池长期平均运行效率的评价方法,对影响调蓄池类型选择与运行效率的主要因素--雨天出流的初期效应及悬浮物沉降性能进行了分析.针对上海市苏州河沿岸排水系统雨天出流的特性,提出了调蓄池形式优化选择的策略:对于存在一定初期效应且沉降性能差的合流制系统采用存储池;而对于基本无初期效应、出流中污染物沉降性能好的分流制系统采用存储-沉淀池.  相似文献   

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