Water Leakage Research Articles

Experimental assessment of crack prediction methods in international design codes for edge restrained walls

Through cracking resulting from external restraint of early-age thermal and long-term shrinkage strain is a significant issue in the construction industry as it causes leakage in water retaining and resisting structures. Concerningly, a recent field study found restraint induced crack widths to frequently exceed crack widths calculated in accordance with UK design practice (BS EN 1992-3 and CIRIA C766). Due to a lack of pertinent data, the reasons for this are uncertain. This paper compares measured and predicted crack widths in a series of 12 full-scale edge restrained walls constructed in the laboratory. The tests examine the influence on cracking of key parameters including concrete mix design, wall reinforcement ratio, wall aspect ratio and relative wall to base cross-sectional area. The measured and calculated crack widths are compared at first cracking and at the end of monitoring. Two types of behaviour were noted in the tests, dependent on when the first cracks formed. Cracking either occurred at early age, within 24 h of stripping the formwork, or later due to restraint of combined early age thermal contraction and shrinkage. The final crack widths were greatest, by a considerable margin, in walls where cracks formed at early age, despite the initial cracks being very narrow. BS EN 1992-3 gives the best estimates of crack width in the two walls that cracked at early age. Crack widths in these walls were significantly underestimated by C766. In the other 10 walls, which cracked later, C766 tends to give the best estimate of crack width.

Water Harvesting in the Jimin Basin by Using Remote Sensing Techniques and Geographical Information Systems

What is meant by water harvesting is the process of collecting and storing surface runoff water resulting from precipitation to benefit from it for agricultural purposes, feeding underground storage, and providing drinking water for humans and animals. For the basin, especially evaporation, where the number of hours of the solar surface was recorded in two Kirkuk stations (11) hours/day, respectively, and it was recorded in Chamchamal station at about (12) hours/day, while it decreases during the winter months, as it reaches about (5) in Chamchamal station, respectively, while in Kirkuk station reached (6) hours/day, respectively. The highest monthly rates were recorded during the winter months (December) by (66.4, and 66.7%) for both stations (Chemchamal-Kirkuk), respectively. While its lowest monthly rates were recorded during the summer months (July and August), when it reached (24.2%), which can predict the presence of saturated soil, which reduces filtration and leakage after rain falls and generates surface runoff, which can be harvested and utilized from the water. For both stations, they are spatially and temporally dissimilar, as the highest average of their monthly totals was recorded during the winter seasons in Chamchamal station in January and February to (92.9 mm) respectively, then it decreased relatively during December as recorded (90.1 mm). The annual rainfall was recorded in both stations (Chemchamal-Kirkuk) (502.3, 337.7 mm). It is clear from the foregoing that the plant has an important role in the presence of organic matter in the soil, which increases the seepage of falling rainwater and does not generate surface runoff. Therefore, the areas that are characterized by the presence of vegetation can be exploited by applying the harvesting methods designated for such areas that are characterized by water leakage into the ground, and therefore the soil is radiant with moisture, which can be cultivated directly, especially by applying the technology of mountain terraces that works to impede water and increase its seepage into the soil layer, especially These areas are characterized by their height and exposure to soil erosion after heavy rains.

Novel numerical model to simulate water seepage through segmental gasketed joints of underwater shield tunnels considering the superimposed seepage squeezing effect

The water leakage through segmental joint gaskets has become a major concern that adversely affects the normal serviceability of underwater shield tunnels throughout the construction and operational periods. Therefore, it is of great significance to investigate the sealing performances of the joint gaskets, which directly helps evaluate the waterproof capacity of underwater shield tunnels. To date, the numerical modeling plays an irreplaceable role in the analysis on the waterproof capacity of the joint gaskets. Nevertheless, conventional methods tend to ignore the self-sealing effect induced by the water seepage pressurization, thus failing to reveal the progressive evolution of the water infiltration process through the joint gasket. To remedy this defect, this paper proposed a novel numerical model to simulate the penetration process of the sealing gasket based on the Python language-enabled secondary programming in the ABAQUS software, which could fully consider the superimposed seepage squeezing effect. Based on the proposed model, the waterproof failure process and the dynamic contact stress of the gasket’s water seepage path subject to excessive hydraulic pressure were thoroughly investigated. Moreover, indoor tests on the waterproof capacity of the gasket were also performed to validate the proposed model. It is found that the numerical results from the developed model are consistent with the experimental results. This research will contribute to better understanding of the gaskets’ hydraulic penetration process and more accurate prediction of the maximum waterproof capacity in underwater shield tunnels.

Planning methodology for effective implementation of the rehabilitation policy for drinking water networks

Abstract Algeria is currently experiencing a real water shortage and leaks in the distribution networks, which affect the water supply. To reduce losses, the authorities have adopted a rehabilitation policy that requires resources that are not necessarily available. In this context, the aim of this study is to develop a decision support methodology for managers to enable them to plan urgent rehabilitation and to evaluate the benefits generated. The methodology consists of two phases: the diagnostic phase to identify a set of criteria, taking into account national specificities, and the planning phase, including the choice of Fuzzy-AHP for weighting and PROMETHEE II for ranking. An application is carried out on the Fouka network in Bejaia city (Algeria), consisting of 204 pipes. The application enabled the 204 pipes to be ranked in order of urgency and the benefits generated to be assessed in terms of environmental, economic, social, and technical parameters. The recovered water is significant in the first 60% of rehabilitated pipes. Investment costs are recovered within 3 years of the network being fully rehabilitated. The average reduction in network age is 5 years for every 10% of pipes rehabilitated. Complaints will be 0 after 70% of the pipes are rehabilitated.

Prediction of Water Leakage in Pipeline Networks Using Graph Convolutional Network Method

This study aims to predict leaks in water-carrying pipelines by monitoring pressure drops. Timely detection of leaks is crucial for prompt intervention and repair efforts. In this research, we represent the network structure of pipelines using graph representations. Consequently, we propose a machine learning model called Graph Convolutional Neural Network (GCN) that leverages graph-type data structures for leak prediction. Conventional machine learning models often overlook the dependencies between nodes and edges in graph structures, which are critical in complex systems like pipelines. GCN offers an advantage in capturing the intricate relationships among connections in pipelines. To assess the predictive performance of our proposed GCN model, we compare it against the Support Vector Machine (SVM) model, a widely used traditional machine learning approach. In this study, we conducted experimental studies to collect the required pressure and flow data to train the GCN and SVM models. The obtained results were visualized and analyzed to evaluate their respective performances. The GCN model achieved a performance rate of 94%, while the SVM model achieved 87%. These results demonstrated the potential of the GCN model in accurately detecting water leaks in pipeline systems. The findings hold significant implications for water resource management and environmental protection. The knowledge acquired from this study can serve as a foundation for predicting leaks in pipelines that transport gas and oil.

Hygrothermal Performance of Thick PCM Mortar behind PV Panels in Energy-Activated ETICS Facades

The concept of integrating PV panels into traditional ETICS facades has been developing for several years. Problems concerning the options for passively controlling the temperatures of PV panels with PCM and directing excess moisture out of the wall via diffusion channels have been previously studied theoretically. During this study, real wall-scale experiments were conducted to test the thermal and hygrothermal performance of the wall system in an extreme climatic environment, as well as in a real outdoor environment in Tallinn, Estonia. Finally, a simulation model was calibrated according to the measured data. It was found that in case of test walls with diffusion channels, it was possible to keep the moisture content of PCM mortar under 0.11 m3/m3. Excess water drained out via channels leading to the external environment. Without diffusion channels, the moisture content rose as high as 0.18 m3/m3. Both the experiments and hygrothermal modelling showed that the high moisture content of PCM mortar, caused by water leakage, dropped to 0.08 m3/m3 over 10 solar cycles as moisture escaped via the diffusion channels. PCM mortar with a moisture content of 0.08 m3/m3 endured extreme rain and freeze-thaw cycles without visual damage, and PV panels retained their electrical production capabilities.

Analysis of Common Quality Defects and Prevention Measures of Indoor Waterproof Engineering

During the completion and acceptance of indoor waterproof engineering, there are common quality problems such as ground water seepage, water leakage, water retention and damp walls in toilets, balconies and kitchens. According to all kinds of current waterproof construction acceptance specifications, combined with the site construction experience, this paper analyzes the manifestations and causes of common waterproof project quality problems, and puts forward prevention and control measures and countermeasures, to improve the comfort of the living environment, to eliminate the hidden dangers of waterproof to provide useful reference.

Automated Water Billing and Leakage Detection System

This project deals with automatically collecting a customer’s water consumption and detecting leakages in the water distribution system. For effective water monitoring, metering, data analysis and communication technology are combined in an integrated water bill and leak detection system. Real-time supply and demand data is collected using water meters and smart sensors. The data is analyzed using sophisticated algorithms and machine learning, which can detect patterns and anomalies that could indicate violations. When potential issues are detected, automated notifications are sent for immediate action. By consolidating consumption information with billing software, this solution automates payments while maintaining accuracy and accessibility. Operators can make smart decisions and optimize maintenance with real-time data visualization and reporting. The system encourages water savings, reduces water loss, and increases operational efficiency.

Probability of simultaneous multiple leakages at sections of water networks in the process of localization of hidden water leaks

Hidden leaks from water supply networks account for 50% to 90% of total leakage losses. The presence of two or more simultaneous leaks in a section of the water supply network significantly reduces the accuracy of locating hidden leaks. The method of independent Poisson events and the hypothesis of stationarity, absence of consequences, and ordinariness of leaks are used for the probabilistic description of the problem of multi-leakage in water supply networks. The analytical dependence of the probability of multiple leakages on the specific annual emergency rate of the site, its length and the duration of the localization and repair period is obtained. A generalized semi-empirical equation was obtained for estimating the maximum permissible duration of the localization and repair period depending on the annual emergency rate of the site for a given multi-leakage probability.

Time-series-based habitat model development for surface water management on endangered aquatic plant Isoetes taiwanensis conservation in mountain wetlands

Wetland scientists and ecological engineers are encouraged to comprehend hydrological driving forces for enhancing environmental conservation, ecological restoration, and integrated management. The spatiotemporal distribution and dynamics of aquatic plants are critical for improving their functional niche in mountain wetlands. This study evaluates the hydrological variation of a mountain wetland to determine the adverse and advantageous situations of an endemic and endangered aquatic plant by establishing a time-variant habitat index model considering the inundation frequency and duration of a specific water level. The model was developed and verified by integrating with a field survey of biotic and abiotic data to build the corresponding habitat suitability indices through conducting polynomial regression analysis. The results indicate its capability to effectively quantify the intricate relationship between water level and plant coverage in different places and seasons. The habitat quality can be derived as the combined functions of total scattered and maximum continuous periods of dominant and nondominant water depths. Although the coverage area fluctuated in different seasons, the model reveals significant capabilities to bridge the gaps for reaching the extreme hydrological conditions which might cause the extinction of the endangered aquatic plant Isoetes taiwanensis. The plant is found to be more competitive in the region, implemented by excavation and consolidation, with deeper water depth and higher water conservation. We suggest adaptative water level management at the planning and design phases and rehabilitating these essential habitat patterns to enrich the survival of I. taiwanensis in the dry season. Strengthening the water retention capacity of the bottom soil to reduce water leakage and groundwater seepage velocity may also help achieve integrated management for surface water conservation in the wetland.

Effect of flue gas constituents on boiler tube failure of a captive power plant

Water leakage was reported from one of the superheater tubes of boiler during operation. The power plant is a part of copper ore smelting and refining industry. It was observed, that the leakage took place through cracked region of the tube, which was severely damaged due to chemical attack. Damage occurred due to reaction between flue gas and outer wall of super heater tube. Inefficient treatment of flue gas resulted in retention of metal particles, SO2 gas and particulate within the same in substantial concentration. When the same flue gas was used in boiler, SO2 reacted with tube surface at elevated temperature. The incident lead to wall thinning and deep pit formation over tube surface. Metal particles was fused, adhered to tube surface and triggered secondary cracking during operation. Gradual wall thinning, increment in pit size and crack propagation through thickness resulted in ultimate failure of tube material.

Assessment of Innovative Repair Methods for Corroded Steel Girder Bridges Using the House of Quality Matrix

Across the U.S.A., steel girder bridges experience significant deterioration caused by corrosion, and the current repair methods for corroded steel girders require considerable time and cost. Corrosion is typically found at end-span locations above girder supports at abutments and piers caused by deicers and water leaking from the deck joints. Therefore, there is a need for effective, rapid, and robust repair strategies that can be implemented by bridge maintenance personnel. This paper presents five innovative repair methods for rehabilitating corroded steel girder bridges. The five innovative repair methods were evaluated to select two repair procedures that can be implemented by the local Department of Transportation (DOT) in Indiana. During the evaluation process, typical and critical requirements associated with repair methods for corrosion-damaged steel girders were considered, including robustness, reduction of implementation cost, and time. Furthermore, feedback from the local DOT in Indiana was collected to identify any additional requirements. The evaluation was completed by choosing two innovative repair methods through a selection process called the house of quality matrix, which is a commonly used tool in the consumer product industry. After completing the evaluation, two repair methods, “sandwich panel” and “web strengthening with diagonally oriented angles,” were selected.

Reducing the urban environment impact of joint leakage of underground prefabricated structures: Waterproof performance improvement of WSR-EPDM gasket

Composite cross-section gaskets with ethylene propylene diene monomer (EPDM) and water swelling rubber (WSR) have been adopted for specific underground prefabricated structures to prevent water leakage. Research on the sealant behavior and waterproof failure mechanism of WSR-EPDM gaskets needs to be strengthened, and this paper presents a combined experimental and computational study to investigate the leakage behavior of WSR-EPDM gaskets. The mechanical performance of the WSR-EPDM gasket based on the 3-stages load-deformation relationship was detected using the electronic universal testing machine. And the waterproof performance of the WSR-EPDM gasket was tested based on the developed waterproof capacity test setup to monitor the water leakage pressure of joints under various combinations of joint openings and offsets. Three groups of mechanical tests and 12 groups of waterproof tests were carried out. Then, a series of finite element models were developed using the coupled Eulerian-Lagrangian method to reveal the failure mechanism of the WSR-EPDM gasket. The hyperelastic behavior of the WSR-EPDM gaskets was described using the two-coefficient Mooney-Rivlin hyperelastic model and verified against the gasket-in-groove mechanical test results. A supplementary parametric study investigated the effect of joint opening and offset. The correlation between gasket contact stress and supplied water pressure was analyzed. Finally, an improved gasket was developed, and the mechanical and waterproofing behavior was evaluated. The results indicated that the joint opening and offset negatively influenced the gasket waterproof behavior. The water-leakage path of the WSR-EPDM gasket was more likely to happen via the gasket-groove interface when the joint offset was larger. Furthermore, the mean contact pressure ratio to the water leakage pressure of 1:1 can be used as the criteria for a preliminary estimate of the potential water leakage path. The improved WSR-EPDM gasket showed excellent waterproof performance, with a maximum increasing ratio of 127.6%. The developed test setup and numerical methodology provide novel insights into the waterproof performance improvement of composite cross-section gaskets in complex situations.

Development and Preliminary Application of Temperature Stress Test Machine for Cast-in-Place Inner Shaft Lining.

Over the past 20 years, as the depth and diameter of shaft lines increased in China, the cracking and water leakage of the inner walls of frozen shafts have become increasingly severe, resulting in significant safety threats and economic losses. Understanding the stress variation patterns of cast-in-place inner walls under the combined effects of temperature and constraint during construction is a prerequisite for evaluating the crack resistance performance of inner walls and preventing water leakage in frozen shafts. The temperature stress testing machine is an important instrument for studying the early-age crack resistance performance of concrete materials under the combined effects of temperature and constraint. However, existing testing machines have shortcomings in terms of applicable specimen cross-sectional shapes, temperature control methods for concrete structures, and axial loading capacity. In this paper, a novel temperature stress testing machine suitable for the inner wall structure shape, capable of simulating the hydration heat of the inner walls, was developed. Then, a reduced-scale model of the inner wall according to similarity criteria was manufactured indoors. Finally, preliminary investigations of the temperature, strain, and stress variations of the inner wall under 100% end constraint conditions were conducted by simulating the actual hydration heating and cooling process of the inner walls. Results show that the hydration heating and cooling process of the inner wall can be accurately simulated. After approximately 69 h of concrete casting, the accumulated relative displacement and strain of the end-constrained inner wall model were -244.2 mm and 187.8 με, respectively. The end constraint force of the model increased to a maximum value of 1.7 MPa and then rapidly unloaded, causing the model concrete to crack in tension. The temperature stress testing method presented in this paper provides a reference for scientifically formulating technical approaches to prevent cracking in cast-in-place concrete inner walls.

Time delay estimation using cascaded LMS filters fused by correlation coefficient for pipeline leak localization

Water leaks are commonly detected using acoustic/vibration sensors, which are sensitive to sounds and vibrations caused by leakage. In practical surveys, the degree of success for leak detection and localization depends on the operating conditions and construction materials of the pipeline in question. In particular, under the condition of low signal-to-noise ratios (SNRs) and small leaks, the traditional localization method based on time delay estimation (TDE) tends to give pseudo peaks, which may lead to appreciable errors in the estimate of the leak position. In this paper, TDE is carried out based on cascaded least mean square (LMS) filters fused by correlation coefficient. Combined with the propagation theory of leak signals in the pipeline, the TDE algorithms using the LMS adaptive filters are introduced for leak localization. It is found that the single LMS filter is replaced by cascaded architectures, further improving its performance for TDE in a low SNR environment. Numerical simulations are presented to demonstrate the best performance for TDE by using the cascaded LMS filters in comparison with the basic cross-correlation, the phase transform generalized cross-correlation and the single LMS filter. This is further verified using some measurements made in the laboratory and field tests.

Morphology and Composition Changes in Fluid Inclusions from Quartz under Progressive Deformation: Case Study of a Vein System in the Western Kelyan-Irokinda Fold Zone (Western Transbaikalia)

Abstract —The behavior of fluids during plastic deformation is studied from the morphology and distribution of fluid inclusions in quartz grains of different microstructure types from a vein system controlled by thrusting and strike-slip faulting in the eastern Sayan–Baikal fold area. The analytical work includes electron backscatter diffraction (EBSD) for quartz microstructure and crystallography, as well as Linkam heating-and-freezing analysis and Raman spectroscopy for the composition of fluid inclusions. The studied fluid inclusions are of seven types that differ in morphology and position in the deformed quartz structure. A model is suggested to describe successive structural changes of quartz aggregates during dislocation sliding and subsequent creep-related recrystallization associated with redistribution of fluid. Fluid inclusions undergo qualitative and quantitative changes due to water leakage at all stages of plastic deformation. The changes occur by two main mechanisms: (i) mass transfer during dislocation sliding at medium temperatures and strain rates and (ii) diffusion creep at low strain rates and high temperatures. The contribution of creep increases gradually with temperature, which maintains the interaction of inclusions with migrating grain boundaries.

Model Test of Surrounding Rock Temperature Field under Different Drainage Structures and Insulation Conditions in High Cold Tunnel

Improper layout of drainage structures and inadequate insulation measures in high-altitude cold areas have resulted in varying degrees of frost damage in numerous tunnels during operation. To address this issue and propose a viable drainage structure layout scheme, this paper analyzes and studies the temperature field distribution characteristics of the lower surrounding rock and drainage structure around high-altitude cold tunnels, as well as the layout of the central drainage ditch and anti-cold water leakage hole. Based on physical model test results of cold area tunnels, the distribution characteristics of the temperature field around the tunnel drainage structure under different insulation conditions are obtained, and a control equation of temperature change along the depth direction is proposed. By comparing and analyzing the differences in temperature field and water flow characteristics of drainage structures under different insulation methods, the setting conditions of different drainage structures are determined. Furthermore, the function relationship between the freezing depth of the lower surrounding rock of the tunnel arch and the air temperature inside the tunnel is established, and the curve of the on-site tunnel freezing depth change is predicted. This study provides valuable insights into the design and construction of drainage structures and insulation measures for high-altitude cold tunnels, ultimately contributing to the prevention of frost damage and ensuring safe and efficient tunnel operation.

Soil Water Movement and Groundwater Recharge Under Different Land Uses in a Flood-Irrigated Area.

The water shortage in agriculture area in China requires to reduce the consumption of excessive water in flood irrigation. Therefore, the dynamics of soil water regime is needed to investigate and water-saving irrigation is necessary to alleviate water shortage. This study investigated the impact of flood irrigation on soil water movement and recharge to groundwater in the Yellow River irrigation area of Yinchuan Plain, China. Combining comprehensive field observation, stable isotopic techniques and water balance simulation, we described the soil water mechanism in vadose zone covered with bare soil in 2019 and planted with maize in 2020. The soil layers affected by precipitation infiltration and evaporation were mainly 0-50 cm, while the soil influenced by irrigation was the entire profile in the mode of piston flow. The maize root took up the soil water up to the depth of 100 cm during the tasseling period. The infiltration and capillary rise in 2020 were similar with those in 2019. However, the total deep percolation was 156.5 mm in 2020 which was about 50% of that in 2019 because of the maize root water uptake. The leakage of ditch water was the major recharge resource of groundwater for the fast water table rise. Precise irrigation is required to minimize deep percolation and leakage of ditch water and reduce excessive unproductive evapotranspiration. Therefore, understanding the soil water movement and groundwater recharge is critical for agricultural water management to improve irrigation efficiency and water use efficiency in arid regions.

An analysis of the effect of syringe barrel volume on performance and user perception.

In the market, there are many types and shapes of syringes. One of the groupings of syringe types is based on barrel volume. The shape of the product design affects performance and user perception. The aim of this study is to investigate the effect of barrel volume on its performance and user perception. We performed analysis following international organization for standardization 7886 procedures on syringe with 1 mL, 3 mL, 5 mL, and 10 mL volume. In addition, a user perception test was conducted on 29 respondents using a questionnaire with the Likert chart method. This study indicates that the bigger the syringe volume, the larger the dead space and the force to operate the piston are. A larger syringe volume also raises the volume that changes due to the plunger position increase. Meanwhile, the barrel volume does not affect water and water leakage, as we did not observe any leak during the syringe tests in our experiment. In addition, the user perception test shows that the barrel's length influences the ease of device control during the injection. The volume of the barrel negatively correlated with its effect to the environment. The safety features of all syringes are similar except for the 3 mL syringe, which has a value of 0.1 points difference to other syringes.

An Embedded Smart System for Water Monitoring and Leakage Detection of Storage Tanks

An Embedded Smart System for Water Monitoring and Leakage Detection of Storage Tanks