Water Pressure Monitoring Research Articles

Hydraulic impact of pressure transients from water conveyance tunnel on the complex hydrogeological system: A case study HPP Pirot, Serbia

Hydraulic tunnels, integral components of hydropower plant (HPP) systems, traversing diverse rock masses, pose challenges for long-term operation. The study’s main goal was to investigate how hydraulic transients originating from the headrace tunnel transfer through the concrete lining and manifest in surrounding aquifer systems. In this experimental study at the water pressure tunnel of HPP Pirot (Serbia), a novel monitoring approach was employed. The internal piezometers with highly sensitive probes are distributed strategically along the tunnel in different geological environments. This approach involved monitoring of water pressure in the surrounding rock masses and observing the impact of hydraulic transients generated by HPP operation. A comprehensive analysis of monitoring data, incorporating ordinal and partial correlations and considering geological features, provides a profound understanding of groundwater dynamics, pressure transient phenomena, and hydrogeological characterization during HPP operation. The study highlights the complex and spatially diverse hydrogeological environment, emphasizing the varying reactivity of pore pressure during HPP operation, particularly concerning Water Mass Oscillations (WMO). Reactive piezometers near the surge tank demonstrate significant pressure variations, while those located further away display synchronous pressure changes with reduced amplitudes. Schematic hydrogeological models have been created based on the hydraulic impacts of HPPs in different geological environments along the tunnel route. The water pressure response enabled aquifer characterization of (1) a thin-layered, low-fissured aquifer closely related to the reservoir, with low influence on WMO transients; (2) a low-fissured, compartment aquifer or non-aquifer with minimal to no influence on WMO transients; (3) a well-structured karst aquifer system influenced by WMO transients; (4) a fault-controlled zone of deep hypogene karst aquifer discharge highly influenced by WMO transients; and (5) an aquifer with a dominant development of the karst conduit system highly influenced by WMO transients. The study highlights the significance of monitoring water pressure within the rock mass as a fundamental element in analyzing the interaction between water pressure tunnels and the hydrogeological environment. Applying the presented instrumentation and methodology facilitates effective monitoring in research areas where pressure tunnels are constructed.

A new distributed water pressure monitoring method for ground subsidence caused by groundwater overexploitation

Groundwater pressure is a key parameter in the analysis of ground subsidence laws and disaster-causing factors. However, existing sensors make it difficult to achieve distributed and accurate measurements of groundwater pressure. This paper presents a new distributed pressure sensor (DPS) based on optical frequency domain reflectometer (OFDR) for groundwater pressure accurate measurement. The comprehensive temperature influence coefficient was proposed to eliminate the influence of temperature. Tests were conducted to verify the performance of the DPS and analyze the influencing factors. Finally, the proposed method was applied to on-site monitoring of groundwater pressure in Ningbo, China. The test results show that a smaller helically wound pitch length of the fiber optic and a larger diameter piezoresistive element are conducive to improving the sensitivity of the sensor. The on-site monitoring results indicate that the DPS has obvious advantages over traditional pressure sensors and is an innovative means for groundwater pressure measurement.

Prediction of stratified ground consolidation via a physics‐informed neural network utilizing short‐term excess pore water pressure monitoring data

Prediction of stratified ground consolidation via a physics‐informed neural network utilizing short‐term excess pore water pressure monitoring data

Hydraulic Transient Impact on Surrounding Rock Mass of Unlined Pressure Tunnels

The frequent pressure pulsations due to hydraulic transients in hydropower plants induce cyclic loading on the rock mass that may contribute to increased instances of block falls and increased risk of tunnel collapse over the power plant lifetime. This study focuses on understanding the effect of frequent start and stop sequences of hydropower in unlined pressure tunnels. For this purpose, data from a pore water pressure monitoring system is utilized, which was installed at the downstream end of the headrace tunnel at the 50 MW Roskrepp hydropower plant in southern Norway. The objective of this study is to analyze the recorded data and quantify the impact of the hydraulic transient on the surrounding rock mass in the unlined pressure tunnel. The monitoring of pressure data over several years clearly shows that frequent load changes could cause a considerable effect on the rock mass and constituent joint system. A delayed response of the pressure in boreholes in the rock mass compared with inside the tunnel is seen in all start and stop sequences and is considered to be the main reason for instability caused by transients. The response of pore pressure in boreholes is greatly influenced by the characteristics of joints. The results show that the start sequence and shorter shutdown duration exert a greater impact on rock mass as compared to the stop sequence and longer shutdown duration. Therefore, it is recommended to increase the shutdown duration so that the impact can be minimized to increase the tunnel lifetime. This study recommends implementing a more conservative design approach in tunnels with weak rock masses in projects that involve frequent load changes.

Experimental Study on Pore Pressure Variation and Erosion Stability of Sandy Slope Model under Microbially Induced Carbonate Precipitation

With the development of a free trade port on Hainan Island, the construction of tourist roads around the island is currently underway. However, the weather conditions on Hainan Island, which include strong typhoons and rainstorms, pose challenges for the construction of highway-cutting slopes on the coastal weak sandy terraces. These slopes are susceptible to sand loss and erosion from rainfall. To address this issue, MICP green spray irrigation solidification technology is used to strengthen the sandy cutting, and pore water pressure monitoring is carried out on the slope model during MICP solidification and rainfall scour. Combined with the model pore water pressure and flow slip failure pattern, a dynamic analysis was conducted. The results show that MICP sprinkler irrigation technology can solidify the surface of the slope model in a short time, and after three sets of rotation reinforcement, the model achieved a cementation depth of 4 cm, with a well-reinforced surface and closely connected sand samples. Under the erosion effect of simulated rainfall intensity, the sand loss of the slope was weakened, without damage to the sand binding, and the integrity was enhanced. The cementation between the sand grains facilitated the conversion of most of the rainfall into runoff. However, despite these efforts, the slope eventually slid after 150 s. During the sliding process, the leading edge of the slope model lost sand and became unloaded, and the failure mode was graded a creep slip failure. Finally, the slope was divided into several blocks due to the continuous expansion of cracks following the slope failure. The erosion stability of the sandy slope under heavy rains was optimized and the sand loss was prevented effectively. This study proposes a new method of MICP remediation techniques that serve as a new test basis for the practical application of MICP technology in engineering projects.

Theoretical solution and failure analysis of water pressure on lining of deep-buried non-circular hydraulic tunnel based on the equivalent hydraulic radius method

The water pressure distribution acting on non-circular hydraulic tunnels have always been an important and crucial issue in deep-buried tunnels and caverns, due to its complexity, variability and potential threats to the stability of surrounding rock and the safety of lining structure. This research proposes an accurate axisymmetric analytical solution for water pressure and seepage discharge on the surface of surrounding rock, the lining and grouting circle under high external and internal water pressures, by introducing an equivalent hydraulic radius method in to seepage theory in fractured media. Then, the distribution law of seepage pressure within different distances from the tunnel wall is derived by theoretical analysis. The accuracy, superiority and applicability of the theoretical solution based on the equivalent hydraulic radius are verified sufficiently. The maximum errors of the theoretical solution are less than 15%, 18% and 5.98% respectively, when compared to the numerical solution, the in-situ water pressure monitoring data and the theoretical solution based on the conformal mapping. And the proposed theoretical solution is much closer to the numerical solution than the existing equivalent methods. Moreover, parameters of each part of the composite lining are optimized. Increasing 10% of the original of the permeability coefficient of the composite lining can maximally reduce the external water pressure, and the maximum principal stress and displacement of the composite lining can be effectively reduced by comparing the contour of the maximum principal stress and displacement before and after parameter optimization. Furthermore, by comparing the excavation damage zone distribution before and after parameter optimization, the shear failure occurring in the composite lining is significantly reduced, and the stability of the composite lining structure can be improved. The conclusions could provide important guiding theoretical value for the further study of water pressure distribution acting on non-circular hydraulic tunnels as well as for the correct grouting and drainage designs.

Propagation behavior of hydraulic fractures in shale under triaxial compression considering the influence of sandstone layers

The shale-sandstone interbedded reservoirs are widely distributed in China and the natural gas reserves are huge, and the particularity of this type of reservoir has brought great challenges to hydraulic fracturing design. In this respect, laboratory tests modelling the hydraulic fracturing process in the horizontal well under true triaxial compression were carried out based on real rock specimens. Considering factors such as stress state, sandstone proportion, and natural fractures, the spatial morphology and influence mechanism of hydraulic fractures were studied. Besides, based on acoustic emission (AE) monitoring and real-time monitoring of water pressure, the influence of sandstone layers on the propagation behavior of hydraulic fractures was further investigated. The results show that, the fracture morphology in sandstone is relatively simple, while the fracture morphology and orientation in shale are more complex due to serious bedding interference. A large vertical stress difference is the guarantee for realizing hydraulic fractures penetrating multiple lithologic layers, and the long distance between wellbore and shale-sandstone interface reduces the probability of the hydraulic fracture reaching the sandstone layer. Whether hydraulic fractures passed through the shale-sandstone interface can be judged from the fluctuation characteristics of the water pressure curve and the AE signal. The research results are expected to provide theoretical support for the efficient exploitation of shale-sandstone interbedded reservoirs.

Guest Editorial: Emerging Trends and Challenges in Internet-of-Underwater-Things

Internet-of-Underwater-Things (IoUT) is a network of smart interconnected underwater objects. Recently, IoUT has shown its applicability in numerous scenarios such as marine life monitoring, off-shore exploration, underwater lost-treasure discovery, sports, assisted navigation, location awareness, environmental monitoring (e.g., monitoring of water quality, water pollution, water pressure or water temperature), water-based disasters (e.g., tsunami or nuclear accident), defense systems (e.g., surveillance systems or submarine detection) and several other applications. Even though IoUT systems are key enabler in underwater communication, they face challenges due to unreliable transmission medium, unstable radio signals, limited range, low bandwidth, inborn noise, low transmission rate, slow propagation speed, node mobility, lower resources and limited battery capacity. These challenges cause issues in channel modeling, optimal routing, security, privacy, communication overhead, congestion control, packet error rate, packet latency, energy consumption etc. In this respect, this Special Issue (SI) aims to address some of the aforementioned challenges.

Numerical interpretation of regressive localized internal erosion in a real-scale levee physical model

This paper presents the numerical interpretation of a recent experiment on a real-scale levee physical model, in order to investigate the process of Backward Erosion Piping (BEP) and validate a recently proposed finite element formulation able to model both the simultaneous processes observed in backward erosion piping, i.e. the propagation of the pipe tip and the enlargement of the conduit cross-section, as well as the time-dependent effects. In previous papers, the numerical formulation already demonstrated its ability in reproducing available experimental data of full-scale physical models of levees, e.g. for the IJkdijk and for the Delta Flume tests. In the present work, as a further validation for the aforementioned formulation, we consider the numerical interpretation of the regressive localized internal erosion observed in the newly constructed real-scale levee at the Flood Proof Holland facility test site in Delft, The Netherlands. This test was mainly focused on the experimental evaluation of the time-dependent effects typically observed in these phenomena. To this purpose the levee foundation was equipped with an effective and accurate pore water pressure monitoring system. The aforementioned formulation was considered for the numerical interpretation of the test, in view of its ability in modeling the time-dependent effects in backward erosion piping. Indeed, a good agreement between calculated and measured piezometric heads and pipe tip propagations was obtained.

Analysis and prediction of fire water pressure in buildings based on IoT data

Indoor fire water supply system is an important guarantee for building fire safety, and the design parameters such as water flow and water pressure need to meet the requirements of fire prevention regulations. Based on the monitoring data of the Internet of Things (IoT), this paper took an office building as an example to analyze the water pressure variation trend of the building's indoor fire water supply system, and then predict it based on the historical water pressure drop rate fitting and Long short-term memory (LSTM) method. It is found that the variation of water pressure is periodic, and this trend was analyzed from the perspective of physical structure of the indoor fire water supply system. Furthermore, due to the regularity of water pressure variation, the prediction results are generally good. With historical water pressure drop rate fitting, the prediction accuracy is relatively higher, and the abnormal change points of water pressure can be discovered, but the water pressure value needs to be reset for further prediction; while the LSTM method is self-adaptive, when the frequency of water pressure monitoring is high and the amount of water pressure data is large, the LSTM is more suitable. • The water pressure variation of the office building's indoor fire water supply system is periodic. • With historical water pressure drop rate fitting, the prediction result is higher. • The LSTM prediction method is self-adaptive and more suitable for large amount of data.

High-precision fiber optic liquid level sensor based on fast Fourier amplitude demodulation in a specific range of spectrum

This study presents a fiber optic liquid level sensor (FOLLS) by acquiring information from the amplitude of spectral fast Fourier transform (FFT) in a specified narrow wavelength range. The sensing light path is simply formed by embedding a section of Panda-type polarization-maintaining fiber (PMF) into the sensing arm of a conventional Michelson interferometer (MI) structure. The output composite spectrum consists of two parts: the fine interference fringes due to MI optical path difference (OPD) and the envelope fringes stemming from the PMF’s birefringence. By applying liquid level variations on the sensing structure, shifts in envelope wavelength indicate a sensitivity of −0.193 nm/cm, and a liquid level resolution of 1 mm can be easily acquired. Furthermore, by demodulating the amplitude after spectral FFT in a specific narrow wavelength range, and intensity sensitivity of 1.906 dB/cm is achieved, leading to a greatly improved overall resolution of 0.03 mm in liquid level measurement. Besides, the sensing element is sealed and packaged by two sheets of silicone rubber, which can be thrown into liquid when in use, thus easing the sensor installation. Moreover, due to the proposed demodulation method, the sensor is insensitive to the light source power jitter, reference arm phase shift and optical spectral analyzer wavelength shift. Therefore, the merits of the proposed sensor include high precision, high stability, ease of installation, which are beneficial in pore water pressure and liquid level monitoring.

Design and Implementation of IoT-Based Water Pipe Pressure Monitoring Instrument

The water pressure monitoring system in the PDAM pipeline networks has been successfully developed for operation and maintenance of water leaks in a real-time manner. This research aims to design a water pressure monitoring system in operational piping networks to identify anomalies as early as possible. The system is built using a microcontroller, a 1.2 MPa fluid pressure sensor and a control system equipped with a GSM wireless communication module, an Analog to Digital Converter module with 16-bit resolution, a real-time clock peripheral, an OLED display 128x64, and a micro SD card. The developed system was tested in a pressure range of 0.200 - 0.800 bar with 30 repetitions with a RMSE of 0.058 bar. This system has a deterministic coefficient of 0.885 against a standard manometer. The system implemented in the field successfully sends data to the server with a success rate of 96.0%. Data is displayed on a monitoring dashboard that can be accessed via a computer or smartphone.

Research on FBG Technology Applied in Highway Soft Foundation Pore Pressure Monitoring

The pore water pressure monitoring of soft ground pavement is one of the important technical links in highway construction monitoring. The use of traditional electrical measuring instruments to monitor pore water pressure has disadvantages such as low degree of automation, non-real-time data transmission, and high manual monitoring costs. However, fiber grating monitoring technology has developed rapidly due to its advantages of stable data transmission, convenient collection, and dynamic monitoring. . Therefore, relying on the soft foundation pore water pressure monitoring project of Jiujiang Ring Expressway, the monitoring principle of the fiber grating seepage pressure sensor and the buried installation technology in the soft foundation are introduced. Through the long-term monitoring practice on the construction site, it is confirmed that the optical fiber monitoring system is applied to the soft foundation. The stability of base pore water pressure monitoring provides a reference for similar monitoring projects and engineering construction.

Integrating local pore water pressure monitoring in territorial early warning systems for weather-induced landslides

A methodology designed to integrate widespread meteorological monitoring and pore water pressure measurements is proposed. The procedure is tested in 30 hydrological basins highly susceptible to weather-induced landslides in Norway. The following data are used: a catalog of 125 weather-induced landslides in soils registered between January 2013 and June 2017, widespread meteorological monitoring data employed in a territorial warning model, and pore water pressure measurements retrieved from boreholes installed for a variety of geotechnical projects. The territorial warning model is initially applied to identify the warning events and the correspondent warning level in the test areas over the analysis period. Afterwards, a method for assessing the territorial warning events by analyzing the trends of the monitored pore water pressures is proposed. Finally, an augmented territorial warning model is calibrated and validated using statistical indicators widely adopted in literature. The analysis of the results reveals a satisfactory correspondence between days with landslides and the warning levels provided by the augmented territorial warning model. A final comparison between the results of the model calibration and the model validation highlighted the consistency of the model performance, once the three model parameters are adequately set.

Research on the Early Warning Method of Water Delivery Pipeline Detonation Based on High-frequency Water Pressure Monitoring

In order to study a novel monitoring method suitable for pressure water conveyance project, the fiber grating pressure sensor was adopted for monitoring the water pressure of in-service glass fiber reinforced plastic mortar pipeline. An emptying valve was used in the prototype test to simulate the leakage process and the dynamic water pressure process was recorded effectively by the fiber grating pressure sensor with high frequency and high precision. According to prototype test results, a fluctuation analytical method was proposed, which uses random average pressure as the equilibrium standard value. Meanwhile, an early warning system against pipe failure was developed based on this method. The system was verified by the simulated leakage tests, and the results show that the system could alarm the leakage of more than 0.25% of pipeline design flow, and the positioning accuracy was 10 m–20 m.

Analysis of Model Tests of Rainfall‐Induced Soil Deposit Landslide

A large number of deposit landslides are induced by rainfall, and those with different weak layers may be subject to catastrophic failure. This research investigates the rainfall infiltration effect on the stability of deposit landslides with a weak layer at different slope angles. Four rainfall physical model tests were conducted with fixed double penetration artificial rainfall technique and dynamic sensor technologies by using the rainfall test methods as modified in the paper. Deformation and mechanics parameters, as well as water content parameters in the key position in the deposit landslide, were monitored by means of various displacement monitoring sensors, dynamic soil pressure sensors, pore water pressure (PWP) monitoring sensors, and water content sensors. The results show that, under the same rainfall conditions, the rule of displacement and mechanical changes of deposit slope with different angles are similar, that the displacement, soil pressure, and PWP are characterized by two stages of rising and falling, and that the displacement of deposit slope with weak layer remains creep after rainfall. In addition, the displacement at the rear edge of the slope with a small angle is larger than that at the front of the steep slope, but the displacement in the front of the slope is opposite. Furthermore, the slope with a smaller angle is prone to form a tensile crack in the back of the slope, and its deformation and failure have the characteristics of a progressive and thrust‐type landslide. While the failure in front of a steep slope (slope angle more than 60°) occurred first, the slope failure was characterized by sudden and retrogressive modes. The mathematical analysis of the model is also conducted which shows that deformation and failure can be divided into three stages, i.e., creep inoculation, accumulation uplift, and speed‐up sliding. The test results can provide a reference for the investigation, design, and assessment of similar deposit slopes.

Hydrological response to the Sea of Galilee 2018 seismic swarm

Co-seismic and post-seismic groundwater response to the Sea of Galilee 2018 seismic swarm, along with other teleseismic earthquakes are analyzed in nine water pressure monitoring wells, with high sampling rates (40 sps). The largest event of the swarm (Mw 4.6) caused significant water level oscillations of 0.216 bar (2.16 m) and sustained water level drop of 0.121 bar (1.21 m). The response of groundwater to this event and two other distant large events include co-seismic oscillations, co-seismic undrained sustained change, and post seismic drained change. In addition, the proximity of the earthquake swarm to high resolution monitoring wells provides an opportunity to analyze the changes in the oscillations’ amplitudes of most events. The ratio of the water level to ground motion acceleration amplitudes increased after the Mw 4.6 event, suggesting that the aquifer poro-elastic properties have changed. These co-seismic amplitude changes are more sensitive measure than the water level response to earth tides that showed no significant change in the phase and amplitude associated with any of the events. The maximum amplitude of the oscillations is correlated to the amount of drained response, suggested to be caused by activation of a nearby fault and drainage of water between aquifers. The undrained behavior is related to poro-elastic properties changes within the aquifer and depends on the duration of the oscillations. Details of the groundwater high sampling rate can shed light on deformation processes that were described previously as step like changes.

Sistem Monitoring Tekanan Air pada PDAM Gianyar Berbasis Web

Regional Water Company (PDAM) Gianyar Regency is one of the regionally owned companies in Gianyar Regency. Gianyar PDAM is responsible for the availability of clean water for consumers in the Gianyar region and its surroundings. In a water distribution system, the PDAM monitors water pressure in the pipeline so that water is guaranteed to flow to the customer. During this time the system of recording water pressure on the manometer installed in each particular zone is done manually using report paper. The difficulty caused is the slow monitoring of water pressure reported by the recording officer to the distribution officer, so that the water distribution process becomes stagnant which ultimately harms the customers and the PDAM itself. This study aims to create a system that can record water pressure which makes it easier for the distribution head to get information quickly. With the research phase which includes data collection techniques, system analysis, and system design to maximize research and implement systems and tests on each system, it can be concluded that the system that has been made can run well and as expected. The functional features generated in this study are the dashboard graph of the average water pressure per month, processing master employee data, processing village master data, processing master manometer data, processing schedule data, manometer monitoring by officers, manometer monitoring by admin and manometer monitoring report .

Comparison Among Several Subsea Ground Settlement And Pore Water Pressure Monitoring Instruments In Offshore Deep-Water Channel Project

The monitoring of subsea ground settlement and pore water pressure is key indexes for evaluating the safety of offshore channel engineering cases. The monitoring of settlement and pore water pressure for onshore cases is easy to proposed, and lots of instruments can meet the need. While for offshore engineering cases, the monitoring instruments should survive under extreme bad environment. This paper analyzed several monitoring instruments based on a 12.5 deep offshore channel engineering located at Nanjing city. A suit of instrument was final chosen after comparison.

Optimized Process Control for Operation, Energy, Management, and Maintenance in Boiler Plant Using SCADA

The purpose of this study is to design the SCADA to monitor and control the boiler operation using PLC, and to analyze the efficiency of the boiler. This paper outlines the various stages in the operation of the boiler conversions manually operated, towards the boiler operates in full. Boiler is very important part in industry and it require inspection and monitoring process continuously with a specific time interval. Earlier days this inspection and monitoring process is done with human workers. By done with human workers, there are possibilities of errors with human workers while measuring parameter values in boiler operation process. So it is needed a reliable monitoring system is required to avoid these errors and maximize profit. The automation can be easily done by using Programmable Logic Controller (PLC) and SCADA, by constant monitoring using SCADA that already connected to the PLC using communication cable. In this paper the design and automated development of some techniques used for boiler automation. Boiler automation includes the monitoring of water level, pressure and temperature using different sensors .