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1.
作为地下空间信息测绘工作的一个重要部分，基于排水管道内部测绘信息的管道缺陷检测越来越受到人们的重视。CCTV技术是一种广泛使用的排水管道内部测绘与缺陷检测技术。近些年基于卷积神经网的人工智能技术在图像识别中取得了巨大成功，受此启发，提出了一种基于卷积神经网络的排水管道缺陷的检测方法，以提高CCTV视频中的管道缺陷检测的自动化和智能化。试验证明了该方法的有效性，其在缺陷识别的准确率和召回率及识别速度上均满足了排水管道缺陷智能检测的需要；同时该方法也已经在深圳市的排水管道检测中得到广泛的应用。 相似文献
2.
为确定适合广州市地下排水管道的修复方法,对广州老城区近100kin2地区进行调查。调查采用管道潜望镜（Quick View,QV）、管道闭路电视（closed—Circuit Television,CCTV）、管道声纳（Sonar）进行综合探测,结果表明,调查区域内的地下排水管道存在的主要问题是破损断裂、错位、路基下沉、管道淤塞现象,其中小直径管道的损坏情况较为严重,尤其是300mm的管道将近报废。针对地下排水管道的调查情况,结合现有修复技术的特点,经过对修复成本及施工的难易性的研究讨论,得出适合多种管道和缺陷类型的翻转内衬法（Cured In Place Pipe,CIPP）和施工要求相对简单的U型折叠法（U-fold）满足要求,并能够产生较高经济社会效益。 相似文献
3.
《国际泥沙研究》2020,35(2):157-170
Mitigation of sediment deposition in lined open channels is an essential issue in hydraulic engineering practice.Hence,the limiting velocity should be determined to keep the channel bottom clean from sediment deposits.Recently,sediment transport modeling using various artificial intelligence(AI) techniques has attracted the interest of many researchers.The current integrated study highlights unique insight for modeling of sediment transport in sewer and urban drainage systems.A novel methodology based on the combination of sensitivity and uncertainty analyses with a machine learning technique is proposed as a tool for selection of the best input combination for modeling process at non-deposition conditions of sediment transport.Utilizing one to seven dimensionless parameters,127 models are developed in the current study.In order to evaluate the different parameter co mbinations and select the training and te sting data,four strategies are considered.Considering the densimetric Froude number(Fr) as the dependent parameter,a model with independent parameters of volumetric sediment concentration(C_V) and relative particle size(d/R) gave the best results with a mean absolute relative error(MARE) of 0.1 and a root means square error(RMSE) of 0.67.Uncertainty analysis is applied with a machine learning technique to investigate the credibility of the proposed methods.The percentage of the observed sample data bracketed by95% predicted uncertainty bound(95 PPU) is computed to assess the uncertainty of the best models. 相似文献
4.
《国际泥沙研究》2020,35(2):171-179
One of the important issues in water transport and sewer systems is determining the flow resistance and roughness coefficient.An accurate estimation of the roughness coefficient is a substantial issue in the design and operation of hydraulic structures such as sewer pipes,the calculation of water depth and flow velocity,and the accurate characterization of energy losses.The current study,applies two kernel based approaches [Support Vector Machine(SVM) and Gaussian Process Regression(GPR)] to develop roughness coefficient models for sewer pipes.In the modeling process,two types of sewer bed conditions were considered:loose bed and rigid bed.In order to develop the models,different input combinations were considered under three scenarios(Scenario 1:based on hydraulic characteristics,Scenarios2 and 3:based on hydraulic and sediment characteristics with and without considering sediment concentration as input).The results proved the capability of the kernel based approaches in prediction of the roughness coefficient and it was found that for prediction of this parameter in sewer pipes Scenario 3 performed better than Scenarios 1 and 2.Also,the sensitivity analysis results showed that Dgr(Dimensionless particle number) for a rigid bed and w_b/y(ratio of deposited bed width,w_b,to flow depth,y) for a loose bed had the most significant impact on the modeling process. 相似文献
5.
It is known that construction of large sewers based on consideration of flow with non-deposition without a bed deposit is not economical. Sewer design based on consideration of flow with non-deposition with a bed deposit reduces channel bed slope and construction cost in which the presence of a small depth of sediment deposition on the bed increases the sediment transport capacity of the flow. This paper suggests a new Pareto-optimal model developed by the multigene genetic programming (MGGP) technique to estimate particle Froude number (Frp) in large sewers with conditions of sediment deposition on the bed. To this end, four data sets including wide ranges of sediment size and concentration, deposit thickness, and pipe size are used. On the basis of different statistical performance indices, the efficiency of the proposed Pareto-optimal MGGP model is compared to those of the best MGGP model developed in the current study as well as the conventional regression models available in the literature. The results indicate the higher efficiency of the MGGP-based models for Frp estimation in the case of no additional deposition onto a bed with a sediment deposit. Inasmuch as the Pareto-optimal MGGP model utilizes a lower number of input parameters to yield comparatively higher performance than the conventional regression models, it can be used as a parsimonious model for self-cleansing design of large sewers in practice. 相似文献
6.
Quantification of groundwater recharge in the city of Nottingham, UK 总被引：13，自引：3，他引：10
Groundwater is an important and valuable resource for water supply to cities. In order to make full and wise use of the asset
value, a clear understanding of the quantities and sources of urban groundwater recharge is needed. The water supply and disposal
network is often an important source of recharge to urban groundwater through leakage from water mains and sewers. An approach
to establishing the spatial and temporal amounts of the three urban recharge sources (precipitation, mains and sewers) is
developed and illustrated using the Nottingham (UK) urban aquifer. A calibrated groundwater flow model is supplemented by
calibrated solute balances for three conservative species (Cl, SO4 and total N), thus providing four lines of evidence to use in the recharge estimation. Nottingham is located on a Triassic
sandstone aquifer with average precipitation of 700 mm/year. Using the models, current urban recharge is estimated to be 211
mm/year, of which 138 mm/year (±40%) is from mains leakage and 10 mm/year (±100%) is from sewer leakage. The wide confidence
intervals result from the scarcity of historical field data and the long turnover time in this high volume aquifer, and should
be significantly lower for many other aquifer systems.
Received: 1 December 1997 · Accepted: 14 September 1998 相似文献
7.
随着越来越重视环境问题,城市污水管道的建设不断增加,大量的污水管道慢慢老化,它们就需要修护和更新。本论文介绍了对污水管道不产生影响的管道检测和评价技术,污水管道防御性维护是非常必要的。 相似文献
8.
Nitrous oxide emissions from urban wastewater were measured in a combined sewer in Bayreuth, Germany. The closed-chamber method was used to evaluate N2O emissions. Nitrous oxide was analysed by gas chromatography with electron capture detector. Longitudinal and daily variations of N2O fluxes were determined. N2O emissions ranged from 0.11…3.8 mg m?2 h?1 depending on the level of wastewater in the sewer. Data indicate that N2O is mainly formed in the biofilm by nitrification and/or denitrification. In laboratory experiments, samples with wastewater and wastewater/biofilm mixture were incubated with and without NaCl. After two hours of incubation, N2O release was in a range of 42…429 ng N2O per millilitre wastewater or wastewater/biofilm. Incubated samples without NaCl addition showed no significant difference between wastewater and wastewater/biofilm mixture. If salt (NaCl) was added before incubation, samples with wastewater/biofilm mixture emitted 4.8 times more N2O than wastewater samples. It is assumed that high concentrations of NaCl inhibit further microbial reduction of N2O to N2. Based on the field data, a first estimate for N2O emission from sewers is 3.5 g N2O per year and person. 相似文献
9.
A simple model which describes the soil–pipe interaction and accounts for the longitudinal soil variation has been developed. It is used for the analysis of the static response of a section of a buried sewer. A probabilistic analysis (Monte-Carlo method) enabling to quantify the influence of spatial variability of the geomechanical characteristics of the soil makes possible to study the parameters which can influence and drive the longitudinal response of a section of sewer. The system response is complex, soil–structure interaction depending on three different stiffnesses: soil stiffness, pipe components stiffness and joints stiffness. Various analyses have been performed to identify the parameters whose influence is the larger. A specific attention has been devoted to the fluctuation scale of the soil properties and to the stiffness of joints. 相似文献
10.
Urban areas are faced with mounting demands for managing waste and stormwater for a cleaner environment. Rainfall information is a critical component in efficient management of urban drainage systems. A major water quality impact affecting receiving waterbodies is the discharge of untreated waste and stormwater during precipitation, termed wet weather flow. Elimination or reduction of wet weather flow in metropolitan sewer districts is a major goal of environmental protection agencies and often requires considerable capital improvements. Design of these improvements requires accurate rainfall data in conjunction with monitored wastewater flow data. Characterizing the hydrologic/hydraulic performance of the sewer using distant rain gauges can cause oversizing and wasted expenditures. Advanced technology has improved our ability to measure accurately rainfall over large areas. Weather radar, when combined with rain gauge measurements, provides detailed information concerning rainfall intensities over specific watersheds. Knowing how much rain fell over contributing areas during specific periods aids in characterizing inflow and infiltration to sanitary and combined sewers, calibration of sewer system models, and in operation of predictive real-time control measures. Described herein is the design of a system for managing rainfall information for sewer system management, along with statistical analysis of 60 events from a large metropolitan sewer district. Analysis of the lower quartile rainfall events indicates that the expected average difference is 25.61%. Upper quartile rainfall events have an expected average difference of 17.25%. Rain gauge and radar accumulations are compared and evaluated in relation to specific needs of an urban application. Overall, the events analyzed agree to within ± 8% based on the median average difference between gauge and radar. 相似文献