Research

15 pages, 6163 KiB

Open AccessArticle

Experimental Study on the Bearing Capacity of Reinforced Concrete Pipes with Corrosion-Thinning Defects Repaired by UHP-ECC Mortar Spraying

by Peng Zhang, Chenkun Gong, Qingqing Wu and Cong Zeng

Appl. Sci. 2023, 13(13), 7800; https://doi.org/10.3390/app13137800 - 01 Jul 2023

Cited by 1 | Viewed by 825

Abstract

The in situ spraying method is widely used because of its advantages as a trenchless pipeline repair technology, including a fast construction speed and close bonding between the repair lining layer and the reinforced concrete pipe. However, current research on high-performance spray repair [...] Read more.

The in situ spraying method is widely used because of its advantages as a trenchless pipeline repair technology, including a fast construction speed and close bonding between the repair lining layer and the reinforced concrete pipe. However, current research on high-performance spray repair materials, the bearing capacity of pipelines before and after repair, and the failure modes between the two interfaces after repair is insufficient. Through laboratory tests designed with multiple sets of control tests, this paper outlines the bearing capacity of reinforced concrete pipelines with corrosion thinning defects repaired with ultra-high-performance concrete. The variation law of the residual bearing capacity of reinforced concrete pipes and the influence of different corrosion degrees, repair thicknesses, and interface forms on the bearing capacity of reinforced concrete pipes were studied following UHP-ECC for pipe repair. The results showed that the bearing capacity of the structure decreased with an increase in the corrosion thickness of the pipeline. After repair with ultra-high-performance concrete, the bearing capacity of corroded pipelines greatly improved. When the corrosion and repair thicknesses were the same, the bearing capacity of the repaired pipeline with different interface forms was very different. After the interface was implanted with nails, spray repair was carried out and the bearing capacity of the pipeline improved the most, followed by the naturally bonded interface. When plastic film was pasted on the repair interface, the bearing capacity of the pipeline improved the least. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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14 pages, 4536 KiB

Open AccessArticle

Experimental Study on Mechanical Properties of Rectangular Reinforced Concrete Pipe with Corrosion Defects

by Zhe Mei, Peng Zhang and Cong Zeng

Appl. Sci. 2023, 13(13), 7570; https://doi.org/10.3390/app13137570 - 27 Jun 2023

Viewed by 643

Abstract

Rectangular reinforced concrete pipes are widely used in various municipal projects. Because they are often located in weak strata in urban areas, they are prone to structural defects such as corrosion, which in turn leads to a decline in the bearing capacity of [...] Read more.

Rectangular reinforced concrete pipes are widely used in various municipal projects. Because they are often located in weak strata in urban areas, they are prone to structural defects such as corrosion, which in turn leads to a decline in the bearing capacity of reinforced concrete pipes and, in severe cases, causes disasters such as pipe collapse. In this paper, the mechanical properties of rectangular reinforced concrete pipes with corrosion defects are studied through laboratory tests, and the influence of the pipe failure mechanism and corrosion depth on the ultimate bearing capacity of pipes is analyzed. A numerical simulation method is used to verify the test results, and the numerical simulation results are In good agreement with the indoor test results. The research shows that the failure mode of rectangular reinforced concrete pipe under TEB test conditions can be divided into an uncracked stage, a crack development stage and a failure stage. With the increase of corrosion depth, the ultimate bearing capacity of the pipe decreases. When the corrosion depth is equal to the thickness of the protective layer, the ultimate bearing capacity of the pipe is more than 30%, and the corrosion depth has a great influence on the mechanical properties of the pipe. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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17 pages, 11775 KiB

Open AccessArticle

Analysis of Acoustic Signal Propagation for Reliable Digital Communication along Exposed and Buried Water Pipes

by Omotayo Farai, Nicole Metje, Carl Anthony and David Chapman

Appl. Sci. 2023, 13(7), 4611; https://doi.org/10.3390/app13074611 - 05 Apr 2023

Cited by 3 | Viewed by 1401

Abstract

Wireless sensor networks (WSN) have emerged as a robust and cost-effective solution for buried pipeline monitoring due to the low cost (a maximum of a few tens of UK pounds (GBP)), low power supply capacity (in the order of 1 watt/hour) and small [...] Read more.

Wireless sensor networks (WSN) have emerged as a robust and cost-effective solution for buried pipeline monitoring due to the low cost (a maximum of a few tens of UK pounds (GBP)), low power supply capacity (in the order of 1 watt/hour) and small size (centimetre scale) requirements of the wireless sensor nodes. One of the main challenges for WSN deployment, however, is the limited range of underground data communication between the wireless sensor nodes of less than 3 m, which subsequently increases deployment costs for a utility owner for buried pipeline monitoring. A promising alternative to overcome this limitation is using low-frequency (<1 kHz) acoustic signal propagation along the pipe. This paper examines the feasibility of using low-frequency acoustic signal propagation along exposed and buried medium-density polyethylene (MDPE) pipes and makes predictions of the potential distances at which reliable data communication can be achieved. Quantification of the acoustic attenuation was performed using both analytical and numerical models in addition to laboratory and field experiments. The predicted acoustic data communication distance ranged between approximately 18 m for an exposed and approximately 11 m for a buried MDPE pipe. These results demonstrate the feasibility of using low-frequency acoustic signal propagation for achieving reliable wireless underground communication. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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22 pages, 4195 KiB

Open AccessArticle

Dynamic Response Analysis of Buried HDPE Pipes under Vibration Compaction Considering the Influence of Buried Depth and Filling Modulus

by Chongqian Ma, Xuan Wang, Jiasheng Zhang, Hao Luo and Yu Zhang

Appl. Sci. 2023, 13(6), 3568; https://doi.org/10.3390/app13063568 - 10 Mar 2023

Viewed by 1835

Abstract

During pavement construction, the gravity load and vibration excitation from vibratory rollers can seriously affect the safety of underground pipelines. However, research on the dynamic response of buried pipelines under the action of large vibration rollers is rarely reported. Therefore, the dynamic response [...] Read more.

During pavement construction, the gravity load and vibration excitation from vibratory rollers can seriously affect the safety of underground pipelines. However, research on the dynamic response of buried pipelines under the action of large vibration rollers is rarely reported. Therefore, the dynamic response of a high-density polyethylene (HDPE) double-wall corrugated pipe under a vibratory roller was studied via field testing and a three-dimensional nonlinear finite-element model was established. This model was used to analyze the influence of filling property and vibration frequency on the dynamic response of an HDPE pipe under a vibration load from a vibratory roller. The results reveal that with the increase of compaction times, the backfill soil keeps changing between over-compaction (loose) and compaction states, and the pipe top pressure also keeps changing. Moreover, at a shallow burial, the pipe top pressure is more obvious when the compaction degree changes. The elastic modulus of filling soil within a certain range can effectively reduce the stress deformation of the pipeline under vibration compaction. However, when the elastic modulus of filling soil exceeds 10 times the initial elastic modulus, the deformation of the pipeline becomes greater than the initial value. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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17 pages, 3729 KiB

Open AccessArticle

Analytical Study of Lateral Buckling of Pipelines with Initial Imperfection Based on Fixed-Fixed Beam Model

by Songxian Wang, Lichen Li, Wenbing Wu, Tianwei Wang and Hao Liu

Appl. Sci. 2023, 13(5), 3227; https://doi.org/10.3390/app13053227 - 02 Mar 2023

Viewed by 1302

Abstract

The beam analysis model and the initial imperfection are predominant factors in analyzing the lateral buckling behavior of submarine pipelines under high temperature. However, the existing beam models do not consider the inhibition provided by the virtual anchor point of the pipeline. In [...] Read more.

The beam analysis model and the initial imperfection are predominant factors in analyzing the lateral buckling behavior of submarine pipelines under high temperature. However, the existing beam models do not consider the inhibition provided by the virtual anchor point of the pipeline. In this study, a fixed-fixed beam model is introduced to simulate the lateral buckling response of a submarine pipeline. This model considers the suppression tension provided by the virtual anchor point during the pipeline feeding-in process, which better reduces the buckling response phenomenon of the pipeline. Based on the assumption of rigid-plastic pipe-soil interaction, the analytical solution of the buckling development of pipeline under full-contact repetitive cosine imperfection is derived. The effectiveness of the fixed-fixed model is verified by comparing with the analytical solutions in other literature. The influence of the imperfection model, the temperature difference, and the soil resistance on the pipeline buckling is investigated. Finally, the size effect of the pipeline on the effective axial force development is discussed. The results show that the pipeline undergoes stress vibration under tensile force, and the frequency and density of the pipeline stress vibration increase with the increase of the initial defect amplitude. Increasing the diameter–thick ratio will significantly increase the bending amplitude and bending stress of the pipeline. Attention should be paid to the fatigue damage caused by continuous stress mutations during pipeline buckling, which could further lead to the structural destruction of the pipeline. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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27 pages, 5915 KiB

Open AccessArticle

A Numerical Investigation of Induced and Embedded Trench Installations for Large-Diameter Thermoplastic Pipes under High Fill Stresses

by Havvanur Kılıç, Perihan Biçer and Sercan Bozkurt

Appl. Sci. 2023, 13(5), 3040; https://doi.org/10.3390/app13053040 - 27 Feb 2023

Cited by 1 | Viewed by 1652

Abstract

The induced trench installation method is applied by placing material with high compressibility on rigid pipes to reduce the earth pressures acting on them. Although the performance of this method for rigid pipes has been investigated, research on thermoplastic pipes is very limited. [...] Read more.

The induced trench installation method is applied by placing material with high compressibility on rigid pipes to reduce the earth pressures acting on them. Although the performance of this method for rigid pipes has been investigated, research on thermoplastic pipes is very limited. In this study, induced trench installation (ITI) and embedded trench installation (ETI) of large-diameter thermoplastic pipes subjected to high fill stresses were investigated by numerical analysis. The numerical model has been verified by considering the field experiments, and a series of analyses were carried out by placing Expanded Polystyrene Foam (EPS Geofoam) in ITI and ETI models. Pipe stresses and deflections were evaluated by considering the pipe diameter, stiffness, and backfill properties. The ITI and ETI models in thermoplastic pipes reduced the stresses acting on the pipes and increased the positive arching regardless of the deflection of the pipe. For pipes with an inner diameter of 0.762 to 1.524 m under 30 m of fill stress, approximately 1.5 to 3.0% deflection occurred. In the ETI model, the horizontal earth pressure in the spring line of the pipe decreased from 65 to 40% depending on the backfill type, and an approximately uniform stress distribution was formed around the pipe. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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15 pages, 5942 KiB

Open AccessFeature PaperArticle

Buckling Behavior of Loosely Fitted Formed-In-Place Pipe Liner in Circular Host Pipe under External Pressure

by Zheng Zeng, Xuefeng Yan, Weigang Xiang, Yahong Zhao and Samuel T. Ariaratnam

Appl. Sci. 2023, 13(2), 679; https://doi.org/10.3390/app13020679 - 04 Jan 2023

Cited by 1 | Viewed by 1221

Abstract

The formed-in-place pipe (FIPP) is a trenchless technology used for pipeline rehabilitation. It is a folded PVC pipe that expands through thermoforming to fit tightly inside the host pipe. However, the deficiencies during the construction of FIPP liners such as insufficient inflation, pipe [...] Read more.

The formed-in-place pipe (FIPP) is a trenchless technology used for pipeline rehabilitation. It is a folded PVC pipe that expands through thermoforming to fit tightly inside the host pipe. However, the deficiencies during the construction of FIPP liners such as insufficient inflation, pipe misalignment and initial deformation will lead to elliptical deformation of the FIPP liner, which affects the load-bearing performance of the liner and makes it susceptible to buckling failure. In this paper, the buckling behavior of loosely fitted FIPP liners under uniform external pressure was investigated by the external pressure resistance test and finite element model. The pre- and post-buckling equilibrium paths verified the finite element model. The results indicated that the value of the dimension ratio will significantly reduce the critical buckling pressure. With the increasing value of liner major axis ratio to host pipe, the reduction effect on the critical buckling pressure caused by the increase in the ovality will diminish. Different values of liner major axis ratio to host pipe and ovality changed the range of the detached portion, which affected the critical buckling pressure. The parametric studies modified the design model from ASTM F1216, which was established to predict the critical buckling pressure of a loosely fitted FIPP liner and reduced the average difference rate from 23.43% to 5.52%. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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20 pages, 34735 KiB

Open AccessArticle

Reliability Estimation for the Joint Waterproof Facilities of Utility Tunnels Based on an Improved Bayesian Weibull Model

by Fang-Le Peng, Yong-Kang Qiao and Chao Yang

Appl. Sci. 2023, 13(1), 611; https://doi.org/10.3390/app13010611 - 02 Jan 2023

Cited by 1 | Viewed by 957

Abstract

Safety issues are a major concern for the long-term maintenance and operation of utility tunnels, of which the focal point lies in the reliability of critical facilities. Conventional evaluation methods have failed to reflect the time-dependency and objectivity of the reliability of critical [...] Read more.

Safety issues are a major concern for the long-term maintenance and operation of utility tunnels, of which the focal point lies in the reliability of critical facilities. Conventional evaluation methods have failed to reflect the time-dependency and objectivity of the reliability of critical facilities, hence reducing the credibility of the analysis results and posing serious risks to the safety of utility tunnels. Taking joint waterproof facilities as an example, this paper focuses on the scientific problem of how to achieve a dynamic estimation of the reliability of critical facilities throughout the project life cycle of utility tunnels. To this end, an improved Weibull distribution model is proposed to incorporate the actual field conditions that affect the reliability of joint waterproof facilities of utility tunnels. Bayesian methods and Hamiltonian Monte Carlo methods are used to realize the posterior estimation of the model parameters via the observed failure data. The case study shows that the posterior prediction results fit well with the actual observation data. The proposed model can be used to estimate in real time such key reliability indicators as failure rate, failure warning time and expected failure time, which facilitate the safe operation and targeted maintenance of utility tunnels. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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16 pages, 5298 KiB

Open AccessArticle

Effects of Vibration on Adjacent Pipelines under Blasting Excavation

by Tiange Qin, Mingze Wu, Lin Jia, Lingli Xie and Li Wu

Appl. Sci. 2023, 13(1), 121; https://doi.org/10.3390/app13010121 - 22 Dec 2022

Viewed by 1465

Abstract

Exploring a pipeline’s response to blast vibration during tunnel excavation is critical for ensuring the safety of the pipeline. In this paper, the vibration monitoring and numerical simulation methods are used to evaluate the dynamic response of ground soil and pipelines to blasts. [...] Read more.

Exploring a pipeline’s response to blast vibration during tunnel excavation is critical for ensuring the safety of the pipeline. In this paper, the vibration monitoring and numerical simulation methods are used to evaluate the dynamic response of ground soil and pipelines to blasts. The attenuation law of peak particle velocity (PPV) and the distribution characteristics of peak effective stress (PES) in pipe sections under different working conditions are studied. The following findings are recorded: (1) A three-dimensional model considering in situ stress is established, and it is found the triangular equivalent load simulation blast effect method used in this paper can effectively reflect the impact of blasting on pipelines. The simulation error is controlled at 7.69%. (2) The ground PPV of each monitoring point decays continuously with the increase in horizontal and axial distance, and the cavity enlargement effect is exhibited above the excavation area. The oncoming blast side PPV of the pipe section is more significant than that behind the blast side. (3) When the blast vibration is transmitted to the pipe, there are differences in the PPV and PES distribution characteristics across the pipe cross-section. The PPV is greater in the lower part of the pipe section, while the PES value is greater in the upper part of the pipe section. The maximum PES of 1.53 MPa is significantly lower than the safety threshold (≤4.6 MPa) at the hazardous-section-monitoring point. (4) A pipeline PPV prediction model is proposed to guide subsequent blasting program development. An empirical formula for the safety criterion applicable to this study is proposed for the scientific implementation of safety assessments for subsequent construction. This safety evaluation framework can be used as a reference for similar projects. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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22 pages, 16631 KiB

Open AccessArticle

Effect of the Geometric Configuration of the Disc Cutter on the Cutting Behaviour in Tunneling

by Yixin Duan, Dajun Yuan, Jun Wu, Xiaojie Deng, Bing Wu and Zhangang Sun

Appl. Sci. 2023, 13(1), 72; https://doi.org/10.3390/app13010072 - 21 Dec 2022

Cited by 2 | Viewed by 1307

Abstract

The disc cutter is a key tool in shield machines that come into direct contact with rock while participating in the removal of rock. Therefore, the reasonable design of the geometric configuration of disc cutters greatly determines the tunnelling efficiency of the shield [...] Read more.

The disc cutter is a key tool in shield machines that come into direct contact with rock while participating in the removal of rock. Therefore, the reasonable design of the geometric configuration of disc cutters greatly determines the tunnelling efficiency of the shield machine. In this paper, the factors influencing the rock-breaking behaviour of disc cutters are studied. Firstly, to ensure the accuracy of the rock-breaking simulation, the parameters of the Holmquist–Johnson–Cook model of the diorite in the Jinan area were determined. Secondly, using ANSYS/LS-DYNA to simulate the rock-breaking process, the influence of the geometric configuration, including blade width and blade fillet, on rock-breaking behaviour was analysed. The results show that with increasing depth of penetration, the contact force increases approximately linearly. The contact force and the rock-breaking influence range gradually decrease with increasing number of blade fillets. In addition, with increasing number of blade fillets, the shape of the influence range gradually transitions from an approximate circle to a trapezoid, and finally to a triangle. With increasing blade width, the contact force and the rock-breaking influence range both increase, but the shape of the influence range remains largely unchanged as a trapezoid. On the basis of these research results, this paper gives some suggestions for the selection and configuration of disc cutters in different strata, which can give some guidance for practical engineering. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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13 pages, 7336 KiB

Open AccessArticle

Model Test Analysis of Subsurface Cavity and Ground Collapse Due to Broken Pipe Leakage

by Fei Tan, Wufeiyu Tan, Feifei Yan, Xin Qi, Qinghua Li and Zhikai Hong

Appl. Sci. 2022, 12(24), 13017; https://doi.org/10.3390/app122413017 - 19 Dec 2022

Cited by 5 | Viewed by 1489

Abstract

Urban ground collapse is a common geological disaster characterized by its invisible nature, particularly in China, and results in significant socioeconomic losses and even loss of life. Underground pipeline breakage is the most common factor leading to urban ground collapses. Hence, it is [...] Read more.

Urban ground collapse is a common geological disaster characterized by its invisible nature, particularly in China, and results in significant socioeconomic losses and even loss of life. Underground pipeline breakage is the most common factor leading to urban ground collapses. Hence, it is essential to study how different types of pipeline breakages initiate the collapse mechanism. In this study, an indoor model test was conducted to directly observe the process of collapse due to broken pipe leakage. A broken pipe was put into a model box and tested by an experimental device. The results showed that among the different pipeline breakage types, vertical damage had the greatest influence on the degree of cavity development and ground collapse. Similarities were observed in the patterns of cavity evolution development and the extent of ground collapse as well, further revealing the significance of the cavity evolution process in predicting ground collapses. Full article

(This article belongs to the Special Issue Advances in Underground Pipeline Technology)

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