Underground Pipes Research Articles

Design and bearing capacity test of prefabricated high-strength thin concrete segments for reinforcing underground box culverts

The application of prefabrication technology in underground engineering has been mostly concentrated in subway tunnels and subway stations. Research on the prefabrication technology of underground box culverts is relatively recent. There is almost no research on the improvement in structural performance of aging box culverts using prefabricated assembly technology. Traditional trenchless rehabilitation technology was developed from the rehabilitation of round pipes and was applied to underground square pipes, such as box culverts, after certain improvements. These methods produce a limited increase in the structural bearing capacity of aging underground box culverts and are time-consuming to construct. In this regard, this paper puts forward the idea of reinforcement with and a design method using prefabricated assembly technology to reinforce the interior of a box culvert with high-strength thin-walled concrete segments. A case study was analyzed and a construction simulation was verified. A full-scale prefabricated high-strength concrete segment was subsequently subjected to horizontal and vertical equal-proportion loading static bearing capacity tests. The results showed that the designed and manufactured prefabricated high-strength concrete segment can be independent of the original structural bearing capacity and without its beneficial constraints to meet the design requirements of bearing capacity. It should be noted that in this experiment, the prefabricated segments eventually suffered shear failure at the splice joints, and attention should be given to strengthening the local structure of the splice joints. The reinforcement method proposed in this paper is also applicable to other similar structures with box-shaped internal space sections.

Multi-objective optimization of shield construction parameters based on random forests and NSGA-II

Metro shield construction will inevitably cause changes in the stress and strain state of the surrounding soil, resulting in stratum deformation and surface settlement (SS), which will seriously endanger the safety of nearby buildings, roads and underground pipe networks. Therefore, in the design and construction stage, optimizing the shield construction parameters (SCP) is the key to reducing the SS rate and increasing the safe driving speed (DS). However, optimization of existing SCP are challenged by the need to construct a unified multiobjective model for optimization that are efficient, convenient, and widely applicable. This paper innovatively proposes a hybrid intelligence framework that combines random forest (RF) and non-dominant classification genetic algorithm II (NSGA-II), which overcomes the shortcomings of time-consuming and high cost for the establishment and verification of traditional prediction models. First, RF is used to rank the importance of 10 influencing factors, and the nonlinear mapping relationship between the main SCP and the two objectives is constructed as the fitness function of the NSGA-II algorithm. Second, a multiobjective optimization framework for RF-NSGA-II is established, based on which the optimal Pareto front is calculated, and reasonable optimized control ranges for the SCP are obtained. Finally, a case study in the Wuhan Rail Transit Line 6 project is examined. The results show that the SS is reduced by 12.5% and the DS is increased by 2.5% with the proposed framework. Meanwhile, the prediction results are compared with the back-propagation neural network (BPNN), support vector machine (SVM), and gradient boosting decision tree (GBDT). The findings indicate that the RF-NSGA-II framework can not only meet the requirements of SS and DS calculation, but also used as a support tool for real-time optimization and control of SCP.

Air Quality and Thermal Environment of Primary School Classrooms with Sustainable Structures in Northern Shaanxi, China: A Numerical Study

In northern Shaanxi, China, the air quality and thermal insulation properties of primary school classrooms should be given more attention due to the relatively low temperatures in the winter, which are significant to the learning processes of students in classrooms. Some sustainable building measures have been designed and constructed to improve the air quality and thermal comfort of classrooms in this region; however, is still unclear how these measures influence air quality and temperature. This study investigated the indoor air quality and thermal environment of a typical primary school classroom in Yulin city, Shaanxi Province, China. The classroom was characterized by sustainable structures, including double-sided corridors and an underground ventilation pipe, for better thermal insulation. By conducting on-site monitoring in the classroom and performing various numerical simulations based on finite element software, the variations in the indoor air quality (carbon dioxide, water vapor concentration) and temperature over time, and under different conditions, were investigated. Moreover, influences (i.e., of corridors, ventilation pipes, window areas, classroom areas, and the number of students) on the air quality and temperature were analyzed. It was proven that double-sided corridors, underground ventilation pipes, and windows with heights/widths equaling 1 could provide energy-efficient and livable building structures for primary school classrooms in the northern Shaanxi region of China.

A new monitoring approach for sustainability assessment of subsurface utilities gasket materials against gasoline and chlorinated solvents: Field evaluation and model development

Once installed, underground concrete pipes with rubber gaskets might be exposed to contaminated soil and groundwater. A pipe material monitoring capsule (PMMC) has been developed to evaluate volatile organic compounds (VOCs) breaking through three types of pipe gaskets; Neoprene, Buna-N, and Viton. The PMMCs were deployed in three contaminated sites: two with gasoline and one with chlorinated solvent (CS). A 3-D field-domain numerical model has been developed for each site to calibrate equivalent hydraulic parameters of each gasket material (ke, D) against benzene and PCE diffusion. The calibrated parameters were then used to compute the concentrations as well as rate of breakthrough of the two study contaminants. A protocol was developed for installing/retrieval of PMMCs to monitor PCE and benzene mass breaking through the gasket material with time. Employing PMMC, benzene concentrations breaking through the Neoprene and Buna-N after 4 months were approximately 70% and 60% respectively of the monitoring wells concentration. The corresponding value for PCE breakthrough after 4 months was 60% for both the Neoprene and Buna-N. Both gasket materials of Neoprene and Buna-N yielded similar performances, including higher rate of contaminant breakthrough compared to Viton. A nonlinear relationship of mass breaking through the gaskets of benzene and PCE with time was discerned from the modeling and field data.

Parametric Analysis of Correlation Functions for Acoustic Monitoring and Assessment of Underground Piping at NPPs

Monitoring and assessment of the technical condition of underground pipelines of process systems important to safety is a relevant task of the ageing management process for existing NPPs. Methods applied in other industries having underground pipelines (oil/gas/public utilities) could be considered. The paper is devoted to theoretical issues of overcoming the interfering redundancy contained in the mutually correlated functions of the acoustic method for inspection of underground pipelines. The method has been tested in intensive leak inspection of urban heating pipelines and potentially could be beneficial for detecting leaks in the early stages of their occurrence in underground pipelines of the essential service water system at NPPs.

Application of the air-pipe rack heat exchanger heating system in residential buildings of Guangzhou

In recent years, underground pipe racks have been extensively constructed in urban areas of China for laying municipal pipelines. As the corridor has a tunnel-shaped underground structure, it can preheat the outdoor air entering from outside in winter. In this study, an underground air-pipe rack heat exchanger (APRHE) system used for residential heating in Xiaoguwei Island, Guangzhou was tested for its thermal performance in winter. Results show that the preheating performance of the APRHE was remarkable and its performance was better at night than during the day. The APRHEs of 150-m long comprehensive and cable trenches can preheat and maintain the air temperature at 21.6 °C and 22.4 °C at night, which were 12.0 °C and 12.8 °C higher than that of the outdoor air, respectively. Their average heating power at night reached 23.9 kW and 24.6 kW, respectively, and the average daily heating energy reached 590.7 kWh and 603.2 kWh, respectively. The preheating performance of the APRHE and its feature of better air quality at night than that during daytime render it a good candidate for residential heating. It is recommended that the preheating length could be set at 100 m. The static and dynamic payback periods of the APRHE residential heating system were estimated at 3.17 and 4.37 years, respectively. The air quality in the pipe rack under the calm wind condition however failed to meet the specifications completely, with the air quality at night being better than that during the day due to the difference in the emission of vehicle exhaust.

Developing a BIM GIS–Integrated Method for Urban Underground Piping Management in China: A Case Study

Underground piping remains one of the key uncertain infrastructures in urban development. Because they are buried underground without a clear vision, the management of the underground piping system is more complicated than other infrastructure. Their records are not usually fully available or accurate, and excavation to validate underground structures is often needed in infrastructure projects. Detection of unexpected obstacles may lead to project delay, increased time spent, and risk of damaging existing piping. The traditional underground piping system management relies on computer-aided design (CAD) drawings and historical empiricism. Still, it cannot meet the strict requirements of infrastructure management nowadays or make the management efficient and sustainable because of the technical limitations and conceptual obsolescence. Therefore, to address this issue, this paper proposes an innovative method that aims to manage the underground piping life cycle. This method is to develop a building information model (BIM) in a geographic information system (GIS) environment by integrating heterogeneous data from both BIM and GIS, which not only achieves three-dimensional (3D) visualization but also seamlessly connects to portfolios, programs, projects, and assets throughout the life cycle of urban underground piping. This is a critical development to integrate and analyze geometric and nongeometric information of aboveground and subsurface building assets and the surrounding environment to stimulate interaction with real-world context. This paper also introduces a case study in China to further prove the feasibility of this method and the format based on it in practice. In the case study, the proposed method is implemented together with a piping sensor to further illustrate the effectiveness of the method over trenchless detection and real-time monitoring for daily management of underground piping. Because the model is visible and the monitoring is in real time, the management would be straightforward. At the same time, this method can analyze, plan, and monitor activity, so the management of urban underground piping systems would become smart. Therefore, an efficient and sustainable management performance can be achieved. This method is meaningful for managing the urban underground piping system, especially for those with expansion, refurbishment, or maintenance for an urban underground piping system.

Deep Learning–Based Monitoring Sustainable Decision Support System for Energy Building to Smart Cities with Remote Sensing Techniques

In modern society, energy conservation is an important consideration for sustainability. The availability of energy-efficient infrastructures and utilities depend on the sustainability of smart cities. The big streaming data generated and collected by smart building devices and systems contain useful information that needs to be used to make timely action and better decisions. The ultimate objective of these procedures is to enhance the city's sustainability and livability. The replacement of decades-old infrastructures, such as underground wiring, steam pipes, transportation tunnels, and high-speed Internet installation, is already a major problem for major urban regions. There are still certain regions in big cities where broadband wireless service is not available. The decision support system is recently acquiring increasing attention in the smart city context. In this article, a deep learning–based sustainable decision support system (DLSDSS) has been proposed for energy building in smart cities. This study proposes the integration of the Internet of Things into smart buildings for energy management, utilizing deep learning methods for sensor information decision making. Building a socially advanced environment aims to enhance city services and urban administration for residents in smart cities using remote sensing techniques. The proposed deep learning methods classify buildings based on energy efficiency. Data gathered from the sensor network to plan smart cities' development include a deep learning algorithm's structural assembly of data. The deep learning algorithm provides decision makers with a model for the big data stream. The numerical results show that the proposed method reduces energy consumption and enhances sensor data accuracy by 97.67% with better decision making in planning smart infrastructures and services. The experimental outcome of the DLSDSS enhances accuracy (97.67%), time complexity (98.7%), data distribution rate (97.1%), energy consumption rate (98.2%), load shedding ratio (95.8%), and energy efficiency (95.4%).

GPR surveys in enclosed underground sewer pipe space

To identify voids around underground concrete sewer pipes, a few studies have introduced conducting in-pipe Ground Penetrating Radar (GPR) inspection systems along the pipes. However, less research has focused on studying the implications of emission, propagation, and reception of electromagnetic waves in the enclosed environment of sewer pipes and their subsequent impact on the resulting radargrams. We defined simulation scenarios where we examine the influence of longitudinal and rotational survey types, antenna frequency, air–gap between antenna and sewer wall, antenna separation, and pipe wall’s mirroring effect on the resulting radargrams. Our results encourage practical considerations for designing in-pipe GPR surveys and outline the subsequent steps for automating the in-pipe GPR surveys.

Monitoring the Bud Mite Pest in a Hazelnut Orchard of Central Italy: Do Plant Height and Irrigation Influence the Infestation Level?

Mite pests are a serious threat for hazelnut cultivations, causing economic losses every year. At least two species of big bud mites, Phytoptus avellanae (Acari: Phytoptidae) and Cecidophyopsis vermiformis (Acari: Eriophyidae), are involved in severe hazelnut bud infestations, even though few studies report P. avellanae as the most present and harmful. Great steps forward have been made in monitoring and management strategies of these mite pests, but a plethora of questions remains unanswered about their ecology and behaviour and how agronomical practices impact populations. Given this precondition, we conducted a four-year monitoring in an experimental hazelnut orchard located in the Viterbo hazelnut district, Central Italy, to: (i) explore the potential effect that irrigation has on mite infestations, (ii) assess if mites locate in a particular band height of hazelnut plants; and (iii) assess the overall field infestation over the years. This study showed that not-irrigated plants and plants irrigated by underground pipe systems were similarly infested. Mites tend to locate in the middle band of the plant, namely from 1.5 to 3 m from the ground. The four-year survey showed an overall increasing infestation trend, with a peak in 2021 for irrigated plants and 2022 for not-irrigated. These results are a milestone for further exploration of the biology and ecology of this pest and to formulate ad hoc monitoring and control strategies as well.

Evaluation of Systems and Technologies Of Underground Pipeline Gallery, Haikou

As the urban areas become denser, the built environment and land resources have limited the scope for further development of the urban areas. Haikou, as one of ten pilot cities to develop underground space, is chosen as the case in this study. Haikou Underground Pipe Gallery is a current underground building structure system that maximizes the utilization rate of land. This study investigates and analyzes the most useful and valuable technologies and systems of the Underground Pipe Gallery by survey and research. The result shows that U-shape construction technology is the most beneficial one and the electrical system is the largest and most widely used one. There are four high-tech applications in the electrical system: load power supply, construction of electrical distribution, power supply cable, and lighting facilities. In addition, a combination of green (sponge project), blue (water control) and gray (underground pipe network) infrastructure is utilized to create an optimal drainage system. It has made good use of the large area of urban green space and rainwater storage facilities.

Ultrasonic Nondestructive Characterization of Blockages and Defects in Underground Pipes.

This article explores the use of a 40-kHz air-coupled ultrasonic array in detecting and imaging blockages and defects in buried pipes with 17-26 wavelengths in diameter at short ranges (approximately 20-60 wavelengths). In particular, the imaging performance of arrays with different numbers of transducers is quantified and compared to establish how many are required for adequate performance. Even low numbers of transducers (<25) are capable of producing -6-dB contours of blockages that match reference images to within 95% by restricting the aperture to maintain element density. However, doing so also limits the resolving power, so arrays with more transducers ultimately image better by having great enough density even at larger apertures. Using <25 transducers also gives a poor contrast ratio of features above background noise (as low as 2), resulting in low tolerance for detection and producing unusable images in some cases. More robust performance is achieved with larger numbers of transducers, which achieves sufficient contrast. All images of planar objects feature a low-amplitude band due to interference between direct reflections and reflections via the pipe wall, which was verified by comparison to simulation. When tested in larger pipes in a deployment case, the low-amplitude band was notably larger but was found to decrease in size at longer ranges.

Polarimetric Chaotic Ground Penetrating Radar for Underground Pipes Detection

A polarimetric chaotic ground penetrating radar (GPR) is proposed to improve the detection accuracy of underground pipes. In this radar system, the chaotic signal is used as the probe signal and the multi-polarization detection mode is employed to gather the GPR data. Furthermore, the laplacian pyramid algorithm is applied to fuse multi-polarization components. The simulations demonstrate that by using the polarization chaotic GPR, the pipe responses are enhanced and their shape and distribution can be accurately obtained. Here, the information entropy, average gradient, spatial frequency, and standard deviation are introduced to quantitatively evaluate the imaging results. The corresponding experiment is consistent with the simulation. Additionally, to verify the performance of the polarimetric chaotic GPR, we compare the polarimetric chaotic GPR with the polarimetric stepped frequency continuous wave GPR. The experimental results show that the proposed radar improves the detection accuracy and enlarges the detection range.

Joint geomorphological and geophysical (electrical resistivity) investigation for the configuration of soil pipe

Soil piping is a complex mechanism of subsurface soil erosion, which results underground conduits (cave/tunnel) of varying dimensions. Soil piping associates with severe consequences, such as land subsidence and land slide. Therefore, the investigation of soil pipe is crucial. However, the study of soil pipe is challenging unless characteristic surficial evidences of the pipe are available. Based on the surficial evidences, soil pipe can be configured with geophysical techniques which in-turn aid in designing precursory measures. Therefore, in the present study, we carried out a combined geomorphological and geophysical investigation to configure the soil pipe at Kinanoor village, Kasaragod, Kerala, India. Based on the vital geomorphological information, we carried out resistivity survey and configured an underground soil pipe of diameter ∼6.5 to 7 m that is seated ∼3 m beneath the surface. This hollow pipe is underlain by the only accessible road of that locality which makes the road vulnerable for transportation. Therefore, a bridge like structure is recommended to construct at the pipe location to stabilize the risk factor. Since the study area is situated on a fringe-slope, the geomorphological investigation points out that the disturbance in natural course of the drainage system and the accumulation of water in the up-slope area due to the man-made activities might act as potential causes for the piping in the area. Therefore, it is suggested not to disturb the natural course of the drainage which may lead to subsidence of the area in future.

Control of Heat Transfer in a Vertical Ground Heat Exchanger for a Geothermal Heat Pump System

This paper presents a mathematical model of heat transfer behavior between the liquid inside vertical underground geothermal pipes and the surrounding ground for heating (in the winter) and cooling (in the summer) modes in a ground heat exchanger (GHE) that can optimize its output temperature. The GHE’s output temperature reaches the appropriate value when the water velocity is lowered enough. Subsequently, the proposed model was applied to a case study of a 400-ton geothermal heat pump system (GHPS) at Oakland University, in both the heating and cooling modes, to assess its validity and improve the GHE’s performance. The model was implemented in MATLAB using an ordinary differential equation (ODE) solver. Four different water velocities were used to demonstrate the significant effect of velocity on the loop exit temperature. Model predictive control (MPC) was designed to optimize the GHE’s output temperature by controlling the water velocity, which could reduce the energy consumption used for heat and water circulating pumps. The results reveal that the acceptable range of the water velocity for Oakland University’s GHE was between 0.35 and 0.45 m/s, which ensured that the heat pump system delivered the proper temperature to provide the Human Health Building (HHB) with a comfortable temperature regardless of the season. The suggested water velocity ranges in vertical single U-tube pipes with diameters of De 25 mm, De 32 mm, and De 40 mm are between 0.33 and 0.43 m/s, 0.35 to 0.45 m/s, and 0.38 to 0.48 m/s, respectively.

Preparation and Characterization of Screen-Printed Cu2S/PEDOT:PSS Hybrid Films for Flexible Thermoelectric Power Generator.

In recent years, flexible thermoelectric generators(f-TEG), which can generate electricity by environmental temperature difference and have low cost, have been widely concerned in self-powered energy devices for underground pipe network monitoring. This paper studied the Cu2S films by screen-printing. The effects of different proportions of p-type Cu2S/poly 3,4-ethylene dioxythiophene-polystyrene sulfonate (PEDOT:PSS) mixture on the thermoelectric properties of films were studied. The interfacial effect of the two materials, forming a superconducting layer on the surface of Cu2S, leads to the enhancement of film conductivity with the increase of PEDOT:PSS. In addition, the Seebeck coefficient decreases with the increase of PEDOT:PSS due to the excessive bandgap difference between the two materials. When the content ratio of Cu2S and PEDOT:PSS was 1:1.2, the prepared film had the optimal thermoelectric performance, with a maximum power factor (PF) of 20.60 μW·m−1·K−1. The conductivity reached 75% of the initial value after 1500 bending tests. In addition, a fully printed Te-free f-TEG with a fan-shaped structure by Cu2S and Ag2Se was constructed. When the temperature difference (ΔT) was 35 K, the output voltage of the f-TEG was 33.50 mV, and the maximum power was 163.20 nW. Thus, it is envisaged that large thermoelectric output can be obtained by building a multi-layer stacking f-TEG for continuous self-powered monitoring.

Development of an Intelligent Based Water Pipelines Damage Control System at the Supply Unit of the Federal Polytechnic Offa, Kwara State

Water is the most valuable means of life sustainability because it is a basic need of all households. The incessant water leakage levels in the water supply network on the mini campus, Federal Polytechnic Offa, is one of the most vital issues to address by the work unit on the School campus. Works unit provides services to all departments on campus, covering an area of the landmass of 1050 hectares with a population of staff and students of approximately 13 000. The work unit is in charge of correctional facilities and operation. The sub-service of the work unit on water supply system comprising a network of 1km of water pipes and 1500 litres capacity storage tower across units. The input system volume in the lose of water supply is approximately 56%, from which a significant proportion is about physical losses. This paper focused on intelligent-based leakage control to replace the traditional method used on campus parameters for backtesting tracing when physical damage becomes visible. However, the result of the study revolves around the design and implementation of a prototype system. The study created a management console as an intelligent decision support system. The realism of the study summarizes various operations by developing intelligent reporting software with data warehouse techniques to facilitate underground leak line pipes tracking.

Application of ground-penetrating radar method to detect underground pipes in PAIR BATAN utility area

Underground pipeline systems dominate today’s urban area landscape. This buried pipeline system will continuously develop along with the utility change. The planning for underground pipelines should be done to avoid mistakes in the pipeline path. Thus, mapping for the underground pipeline is necessary to obtain a database for any upcoming construction development. This research purpose is to detect underground pipelines around utility areas using the ground-penetrating radar (GPR) method. A frequency of 300 MHz was used to acquire GPR data from 6 lines, with a total length of 22.6m for each line and 0.5m for the line spacing. A sequence of processing stages of the GPR data was conducted using matGPR, a MATLAB-based program. Interpretable GPR profiles from each measurement line are obtained after adjusting signal position, removing DC, Dewow, mean filter, gaining, removing global background, and KL-filter. The results show an obvious amplitude reflection anomaly. Each line has similar detected underground pipes from its vertical axis, travel time, and horizontal distance. Clearly, all lines show an obvious contrast anomaly located at the 2.5 m horizontal distance. This most striking anomaly is interpreted as a water tunnel. In comparison, the other five parabolic-shaped anomalies were identified as underground pipes.

A proximate analysis of soil corrosivity to water pipelines in the Manohara Town Planning area of Kathmandu Valley using a probabilistic approach

The facts of early non-performance of iron-based underground water pipes of the Kathmandu Valley (Nepal) are mostly due to the corrosive nature of the surrounding soil factors. A comparatively high percentage of the damage to the water pipelines in Nepal is anticipated, compared with the data reported in the developed countries. For the reasons, the quantitative data analysis of six kinds of the corrosive soil factors (i.e., moisture-holding capacity, pH, electrochemical resistivity, redox potential, Cl−, and SO4 2− ions) of 15 specimens, sampled from the Manohara Town Planning (MTP) area, was carried out using a novel probabilistic model, which is based on the internationally accepted standards (i.e., ASTM, NACE, AASTHO) with some modifications. The corrosivity of each soil factor was categorized into four corrosive groups (CGs) based on the conventionally applied classification methods. The experimentally obtained data of the soil factors were then used for proximate analysis using a new non-deterministic (probabilistic) model to classify the corrosive sub-groups (CSGs) of the soil specimens. This model would be a meritorious method to assess the soil corrosion condition of any area of the country, where the engineers and technologists could be applied pertinent methods or materials for the buried-pipe works in the future.

Derivation of External Exposure Characteristics of Industrial Radiography Based on Empirical Evidence

Background: This study aims to derive the characteristics of each work type for industrial radiography based on empirical evidence through expert advice and a survey of radiation workers of various types of industrial radiography.Materials and Methods: According to a Korean report, work types of industrial radiography are classified into indoor tests, underground pipe tests, tests in a shielded room (radiographic testing [RT] room test), outdoor field tests, and outdoor large structure tests. For each work type, exposure geometry and radiation sources were mainly identified through the expert advice and workers’ survey as reliable empirical evidence.Results and Discussion: The expert advice and survey results were consistent as the proportion of the work types were high in the order of RT room test, outdoor large structure test, underground pipe test, outdoor field test, and indoor test. The outdoor large structure test is the highest exposure risk work type in the industrial radiography. In most types of industrial radiography, radiation workers generally used 192Ir as the main source. In the results of the survey, the portion of sources was high in the order of 192Ir, X-ray generator, 60Co, and 75Se. As the exposure geometry, the antero-posterior geometry is dominant, and the rotational and isotropic geometry should be also considered with the work type.Conclusion: In this study, through expert advice and a survey, the external exposure characteristics for each work type of industrial radiography workers were derived. This information will be used in the reconstruction of organ dose for health effects assessment of Korean radiation workers.