阳泉市城市配水管材的比选

阐述了配水管材费用在管道工程总投资中所占的比例较大，以阳泉市城市配水管材的比选为例，经技术经济比较，确定了适合做城市配水管网的管材。     

Shear stress distribution prediction in symmetric compound channels using data mining and machine learning models

Shear stress distribution prediction in open channels is of utmost importance in hydraulic structural engineering as it directly affects the design of stable channels. In this study, at first, a series of experimental tests were conducted to assess the shear stress distribution in prismatic compound channels. The shear stress values around the whole wetted perimeter were measured in the compound channel with different floodplain widths also in different flow depths in subcritical and supercritical conditions. A set of, data mining and machine learning algorithms including Random Forest (RF), M5P, Random Committee, KStar and Additive Regression implemented on attained data to predict the shear stress distribution in the compound channel. Results indicated among these five models; RF method indicated the most precise results with the highest R² value of 0.9. Finally, the most powerful data mining method which studied in this research compared with two well-known analytical models of Shiono and Knight method (SKM) and Shannon method to acquire the proposed model functioning in predicting the shear stress distribution. The results showed that the RF model has the best prediction performance compared to SKM and Shannon models.     

Water distribution systems flow monitoring and anomalous event detection: A practical approach

Methods to detect outliers in network flow measurements that may be due to pipe bursts or unusual consumptions are fundamental to improve water distribution system on-line operation and management, and to ensure reliable historical data for sustainable planning and design of these systems. To detect and classify anomalous events in flow data from district metering areas a four-step methodology was adopted, implemented and tested: i) data acquisition, ii) data validation and normalization, iii) anomalous observation detection, iv) anomalous event detection and characterization. This approach is based on the renewed concept of outlier regions and depends on a reduced number of configuration parameters: the number of past observations, the true positive rate and the false positive rate. Results indicate that this approach is flexible and applicable to the detection of different types of events (e.g., pipe burst, unusual consumption) and to different flow time series (e.g., instantaneous, minimum night flow).     

A review of data-driven approaches for burst detection in water distribution systems

This study focuses on data-driven approaches for burst detection and classifies them into three categories: classification method, prediction-classification method and statistical method. The performance of these methods is discussed. By analysing uncertainty in burst detection, this paper revealed that non-stationary monitoring data and limitations present in these methods challenge the reliability of detection results. Data pre-processing and probabilistic solutions to deal with the uncertainty are summarised. From these findings and discussions, this paper concludes and recommends that: a) data-driven approaches are promising in real-life burst detection and reducing false alarms is an important issue; b) more comprehensive performance evaluation might be necessary, in particular regarding detectable burst size; c) further research on new methods employing multivariate analysis and a new category based on clustering analysis would be beneficial to tackle uncertainty; d) more focus on the use of pressure data might facilitate burst location and reduce investment in burst detection.     

Evaluation of suitable chlorine bulk-decay models for water distribution systems

Maintaining the chlorine residual is a major disinfection goal for many water distribution systems. A suitable general chlorine bulk-decay model is required for simulation of chlorine profiles in networks to assist disinfection planning/management efficiently. The first-order model is unsuitable due to inaccuracy and inability to represent rechlorination. Three potentially suitable, simple, reactant models were compared. The single-reactant model was found to be unsuitable, as it was inaccurate when restricted to using a single set of invariant parameters. The two-reactant model was more suitable than the variable-rate-coefficient model, although both models were accurate under the same restriction. The two-reactant model was then calibrated against datasets consisting of multiple decay tests for five distinctly different waters. It accurately predicted data reserved for validation over the chlorine concentration range of 0-6 mg/L, using a single set of invariant parameters, and is therefore the simplest, generally suitable model for simulating chlorine profiles in distribution system networks.     

Identifying determinants of urban water use using data mining approach

This study develops a new approach to quantitatively identify the most important determinants of urban water use. The approach is based on a data mining model called genetic programming (GP), which automatically optimizes the structure of the function and parameters simultaneously. With historical urban water use as the target, the GP model identifies the most relevant factors for 47 cities in northern China. Compared with conventional regressive models, the GP model performs better than the double-log model. The Nash–Sutcliffe model efficiency coefficient (NSE) of the GP model is 0.87, while the NSE of the double-log model is 0.79. According to the results of the case study, urban water use is determined by both socio-economic and natural variables. Total population, service industry indicators, green land area, housing area, water price, and rainfall are the most significant determinants of urban water use. Among them, total population, service industry indicators, and green land area clearly have positive contributions to urban water use, whereas rainfall has a negative impact on urban water use. The impacts of housing area and water price are complex, which implies that these determinants may have different impacts on urban water use in different conditions. The new model and new insights developed in this study could be helpful for urban water management, especially for cities that experience water scarcity.     

PE给水管道在城市管网中的应用

从PE管的管材价格和特性，介绍了PE管的优越性及PE管的连接方法，并阐述了PE管在城市道路下的综合地沟内、导向钻技术中的应用，提出PE管施工中应注意的问题。     

谱聚类在给水管网分区优化中的应用

利用图划分技术和图论算法实现给水管网分区。根据给水管网分析,确定分区数量,建立权重邻接矩阵并计算图拉普拉斯矩阵及其特征向量,通过多路图划分对隐藏在特征向量中的聚类信息进行数据挖掘,采用遗传算法和K均值方法实现最佳节点聚类。利用PageRank和最短路径算法确定水表和阀门位置,最终实现给水管网优化分区。实际给水管网模型分区实例表明所提方法在给水管网分区的有效性。     

Multiobjective optimization of water quality and rechlorination cost in water distribution systems

To comprehensively describe the effect of residual chlorine and disinfection by-products (DBPs) on water quality in water distribution systems (WDS) and optimize rechlorination cost, this study developed a multi-objective optimization model of water quality and rechlorination cost. Firstly, chlorine decay and DBPs formation were simulated using EPANET_MSX. An improved non-dominated sorting genetic algorithm II (NSGA-II) with real code was used to optimize the multiobjective model and Pareto fronts could be obtained under different conditions. The results showed that Pareto fronts obtained by average value were better than those obtained by standard deviation and multiplication. Moreover, with the number of boosters increased, maximum value of water quality increased and rechlorination cost decreased. Wall chlorine decay constants were the most important on Pareto fronts, followed by the number of chlorination nodes, proportional coefficients of trihalomethanes (THMs) generation based on residual chlorine consumption, and THMs concentration.     

管棚与注浆技术在隧道突泥中的应用

针对某隧道在施工中发生的突泥灾害,借助TSP-203超前地质探测仪对掌子面前方的地质条件进行了探测,采用长管棚预支护结合小导管注浆对突泥体及周边围岩进行加固处理,经实际证明此方案对于治理隧道突泥是可行的,为今后在流塑状黏土地质中修建隧道积累了一定的经验。     

Real-time performance models for photovoltaic water pumping systems

This purpose of this paper is to develop and validate a model to accurately predict the cell temperature of a photovoltaic (PV) module that adapts to various mounting configurations, mounting locations, and climates while only requiring readily available data from the module manufacturer. Results from this model are also compared with results from published cell temperature models. The models were used to predict real-time performance from a PV water pumping systems in the desert of Medenine, south of Tunisia using 60-min intervals of measured performance data during one complete year. Statistical analysis of the predicted results and measured data highlights possible sources of errors and the limitations and/or adequacy of existing models, to describe the temperature and efficiency of PV-cells and consequently, the accuracy of performance of PV water pumping systems’ prediction models.     

城市供水量预测的数学模型

考虑到时间、温度、水价对供水量的影响,建立了城市供水量预测的差分阻滞模型和神经网络模型,并对其预测结果进行了比较.结果表明:各模型都是可行的,且预测精度很高.考虑到用水负荷的从众心理和水价对个体用水量的影响,利用元胞自动机模型对水价与城市供水量之间的关系进行了模拟,模拟结果表明当社会从众心理一定时,水价的调整对供水量的影响有一个最有效的范围.     

企业供水管网震害预测

根据历史震害资料，分析了供水管道震害特点，给出了供水管网的震害划分标准和震害预测模型，并应用于实际企业供水网络的震害分析。     

Pipe failure rate prediction in water distribution networks using multivariate adaptive regression splines and random forest techniques

ABSTRACT

This paper presents the results of a comparison between multivariate adaptive regression splines (MARS) and random forest (RF) techniques in pipe failure prediction in two water distribution networks. In this regard, pipe diameter, pipe length, pipe installation depth, pipe age and average hydraulic pressure are considered as input variables. Results show that the RF outperforms the MARS which is found as an accurate pipe failure rate predictor. The proposed models are further evaluated through dividing the data into three parts of lower, medium and higher pipe failure rate values. According to the equations produced by MARS technique, three variables of pipe diameter, pipe age and average hydraulic pressure are distinguished as the most effective variables in predicting pipe failure rate in the first case study. Four variables of pipe diameter, pipe length, pipe age and average hydraulic pressure are determined as the most effective variables in the second case study.     

Biostability analysis for drinking water distribution systems

The ability to limit regrowth in drinking water is referred to as biological stability and depends on the concentration of disinfectant residual and on the concentration of substrate required for the growth of microorganisms. The biostability curve, based on this fundamental concept of biological stability, is a graphical approach to study the two competing effects that determine bacterial regrowth in a distribution system: inactivation due to the presence of a disinfectant, and growth due to the presence of a substrate. Biostability curves are a practical, system specific approach for addressing the problem of bacterial regrowth in distribution systems. This paper presents a standardized algorithm for generating biostability curves and this will enable water utilities to incorporate this approach for their site-specific needs. Using data from pilot scale studies, it was found that this algorithm was applicable to control regrowth of HPC in chlorinated systems where AOC is the growth limiting substrate, and growth of AOB in chloraminated systems, where ammonia is the growth limiting substrate.     

Optimal design of urban water supply pipe networks

This paper approaches the optimisation of looped water distribution networks supplied from one or more sources, according to demand variation. The pipe networks have concentrated outflows or uniform outflow along the length of each pipe. An optimisation model coupled with a computational iterative procedure of optimal discharges through pipes is developed on the basis of linear programming for the design of new or partially extended water distribution networks. The optimum solution obtained by this model consists of one or two pipe segments of different discrete sizes between each pair of nodes. The improved linear optimisation model guarantees a high reliability. Also, it is possible to take into account the network pipes with variable discharge on route. Additionally, the paper compares the linear optimisation model to some others, such as the classic model of economical velocities, the Moshnin model and a nonlinear model. This shows a good performance of the proposed model.     

A resilience assessment method for urban water systems

Infrastructure planning for Urban Water Systems (UWSs) is challenged by, inter alia, increasing uncertainty in both demand and availability of water and aging infrastructure, and this is already impacting the climate-proofing of cities. In this context, the idea of resilience has been gradually embraced by the water sector, but the term itself is not yet universally defined, nor operationalised. Here, we propose a methodology to assess the resilience of a UWS, defining it as the degree to which the UWS continues to perform under increasing stress. A resilience assessment method is then proposed as a ‘stress-test’ of UWS configurations, under increasingly more stressful scenarios. We then demonstrate a toolbox assembled for the proposed analysis using, as a proof of concept, a semi-synthetic case study. Results are promising, suggesting that the approach could assist in the uptake and evolution of resilience thinking in strategic water infrastructure decision making, leading to water-wiser cities.     

浅谈聚乙烯（PE）管在城市给水管网中的应用

简要介绍了聚乙烯（PE）管的发展历史与应用特点,较为具体的归纳了PE管在市政给水工程领域的应用（敷设）形式,并结合实例总结了PE管应用中的几点体会,为给水管网的正常运行提供了保障。     

在给水工程中管材的选用问题

本文就塑料给水管与传统给水管材在特性方面的比较,给出了UPVC给水管在施工中的技术要求。     

给水工程中供水管材的选用

介绍了供水管材的种类,对管材的综合性能进行了比较,探讨了管材的选择原则,提出了选择管材的建议,指出只有对运行工况环境条件、施工条件、经济条件等多种因素进行综合比较和分析,才能最终合理确定选用何种管材。