Analysis of faulting destruction and water supply pipeline damage from the first mainshock of the February 6,2023 Türkiye earthquake doublet

In 2023,two consecutive earthquakes exceeding a magnitude of 7 occurred in Türkiye,causing severe casualties and economic losses.The damage to critical urban infrastructure and building structures,including highways,railroads,and water supply pipelines,was particularly severe in areas where these structures intersected the seismogenic fault.Critical infrastructure projects that traverse active faults are susceptible to the influence of fault movement,pulse velocity,and ground motions.In this study,we used a unique approach to analyze the acceleration records obtained from the seismic station array(9 strong ground motion stations)located along the East Anatolian Fault(the seismogenic fault of the MW7.8 mainshock of the 2023 Türkiye earthquake doublet).The acceleration records were filtered and integrated to obtain the velocity and displacement time histories.We used the results of an on-site investigation,jointly conducted by China Earthquake Administration and Türkiye’s AFAD,to analyze the distribution of PGA,PGV,and PGD recorded by the strong motion array of the East Anatolian Fault.We found that the maximum horizontal PGA in this earthquake was 3.0 g,and the maximum co-seismic surface displacement caused by the East Anatolian Fault rupture was 6.50 m.As the fault rupture propagated southwest,the velocity pulse caused by the directional effect of the rupture increased gradually,with the maximum PGA reaching 162.3 cm/s.We also discussed the seismic safety of critical infrastructure projects traversing active faults,using two case studies of water supply pipelines in Türkiye that were damaged by earthquakes.We used a three-dimensional finite element model of the PE(polyethylene)water pipeline at the Islahiye State Hospital and fault displacement observations obtained through on-site investigation to analyze pipeline failure mechanisms.We further investigated the effect of the fault-crossing angle on seismic safety of a pipeline,based on our analysis and the failure performance of the large-diameter Thames Water pipeline during the 1999 Kocaeli earthquake.The seismic method of buried pipelines crossing the fault was summarized.

Sacrificial piles as a countermeasure against local scour around underwater pipelines

Local scour around pipelines crossing rivers or in marine environments is a significant concern.It can lead to failure of the pipelines resulting in environmental side effects and economic losses.This study developed an experimental method to reduce local scour around pipelines with a steady flow of clear water by installing cylindrical and cubical sacrificial piles.Three sizes of sacrificial piles were examined in a linear arrangement.Sacrificial piles were installed on the upstream side of the pipeline at three distances.Maximum scour depth reduction rates below the pipeline were computed.The results showed that sacrificial piles could protect a pipeline from local scour.A portion of scoured sediment around the sacrificial piles was deposited beneath the pipeline.This sediment accumulation reduced the scour depth beneath the pipeline.Analysis of the experimental results demonstrated that the size of piles(d),the spacing between piles,and the distance between the pipe and piles(Xp)were the variables that reduced the maximum scour beneath the pipeline with a diameter of D.For the piles with d=0.40D and 0.64D,X_(p)=4OD was the optimal distance to install a group of piles,and cubical piles could mitigate scour more effectively than cylindrical piles under similar conditions.For the piles with d=D,the greatest reduction in scour depth was achieved at X_(p)=50D with any desired spacings between piles,and cylindrical piles in this dimension could protect the pipeline against scour more effectively than cubical piles.

Study on the Technology of Supplying Water Safely by Long-Distance Pipeline

The extensively built long-distance water transmission pipelines have become the main water sources for urban areas. To ensure the reliability and safety of the water supply, from the viewpoint of overall management, it would be necessary to establish a system of information management for the pipeline. The monitoring, calculating and analyzing functions of the system serve to give controlling instructions and safe operating rules to the automatic equipment and technician, making sure the resistance coefficient distribution along the pipeline is reasonable; the hydraulic state transition is smooth when operating conditions change or water supply accidents occur, avoiding the damage of water hammer. This paper covered the composition structures of the information management system of long-distance water transmission pipelines and the functions of the subsystems, and finally elaborated on the approaches and steps of building a mathematics model for the analysis of dynamic hydraulic status.

Water hammer protection for diversion systems in front of pumps in long-distance water supply projects

For a water supply system with long-distance diversion pipelines, in addition to the water hammer problems that occur beyond pumps, the safety of the water diversion pipeline in front of pumps also deserves attention. In this study, a water hammer protection scheme combined with an overflow surge tank and a regulating valve was developed. A mathematical model of the overflow surge tank was developed, and an analytical formula for the height of the overflow surge tank was derived. Furthermore, a practical water supply project was used to evaluate the feasibility of the combined protection scheme and analyze the sensitivity of valve regulation rules. The results showed that the combined protection scheme effectively reduced the height of the surge tank, lessened the difficulties related to construction, and reduced the necessary financial investment for the project. The two-stage closing rule articulated as fast first and then slow could minimize the overflow volume of the surge tank when the power failure occurred, while the two-stage opening rule articulated as slow first and then fast could be more conducive to the safety of the water supply system when the pump started up.

New insights into the deposition of natural gas hydrate on pipeline surfaces:A molecular dynamics simulation study

Natural gas hydrate(NGH)can cause pipeline blockages during the transportation of oil and gas under high pressures and low temperatures.Reducing hydrate adhesion on pipelines is viewed as an efficient way to prevent NGH blockages.Previous studies suggested the water film can greatly increase hydrate adhesion in gas-dominant system.Herein,by performing the molecular dynamics simulations,we find in water-dominant system,the water film plays different roles in hydrate deposition on Fe and its corrosion surfaces.Specifically,due to the strong affinity of water on Fe surface,the deposited hydrate cannot convert the adsorbed water into hydrate,thus,a water film exists.As water affinities decrease(Fe>Fe_(2)O_(3)>FeO>Fe_(3)O_(4)),adsorbed water would convert to amorphous hydrate on Fe_(2)O_(3)and form the ordered hydrate on FeO and Fe_(3)O_(4)after hydrate deposition.While absorbed water film converts to amorphous or to hydrate,the adhesion strength of hydrate continuously increases(Fe<Fe_(2)O_(3)<FeO<Fe_(3)O_(4)).This is because the detachment of deposited hydrate prefers to occur at soft region of liquid layer,the process of which becomes harder as liquid layer vanishes.As a result,contrary to gas-dominant system,the water film plays the weakening roles on hydrate adhesion in water-dominant system.Overall,our results can help to better understand the hydrate deposition mechanisms on Fe and its corrosion surfaces and suggest hydrate deposition can be adjusted by changing water affinities on pipeline surfaces.

Research on Leak Location Method of Water Supply Pipeline Based on MVMD

At present,the leakage rate of the water distribution network in China is still high,and the waste of water resources caused by water distribution network leakage is quite serious every year.Therefore,the location of pipeline leakage is of great significance for saving water resources and reducing economic losses.Acoustic emission technology is the most widely used pipeline leak location technology.The traditional non-stationary random signal de-noising method mainly relies on the estimation of noise parameters,ignoring periodic noise and components unrelated to pipeline leakage.Aiming at the above problems,this paper proposes a leak location method for water supply pipelines based on a multivariate variational mode decomposition algorithm.This method combines the two parameters of the energy loss coefficient and the correlation coefficient between adjacent modes,and adaptively determines the decomposition mode number K according to the characteristics of the signal itself.According to the correlation coefficient,the effective component is selected to reconstruct the signal and the cross-correlation time delay is estimated to determine the location of the pipeline leakage point.The experimental results show that this method has higher accuracy than the cross-correlation method based on VMD and the cross-correlation method based on EMD,and the average relative positioning error is less than 2.2%.

Criterions and Measures of Route Selection of Shallowly Embedded Long-Distance Oil and Gas Pipeline in Mountain Areas

According to the engineering investigation of long-distance oil and gas pipelines, the criterions and measures of route selection are drawn as follows： the flat landform is the first choice in route alignment. The foot of mountain is the first choice when the route passes by the valley. The route should pass by but the shady and deposited slope and not in sunny and erosive slope as possible as it can. The pipeline should be vertical to contour climbing and descending the mountain except steep slope. Tunnel can be used in crossing foothill. Perpendicularly traversing the river is better than beveling; the worst choice is to put the pipeline along the river. Bypass is the best choice in karsts area. The order of route selection should be pre-choosing, investigation, optimization and adjustment.

THE RISK ASSESSMENT OF THE LONG-DISTANCE OILPIPELINE ENGINEERING

The oilfield construction and long-distance oil pipeline engineering has been developed extensively in China. The risk assessment of oil industry will, however, be an important objective to cope with the development of oil industry , The risk assessment of oil industry has many subjects worthy to be studied.The major purpose of the paper is to research the risk cases of long-distance oil pipeline engineering in Ganshu and Shaanxi provinces.

Analysis on Buckling Performance of Submarine Pipelines During Deepwater Pipe-Laying Operation

Pipes inevitably encounter high ambient pressure and bending moment during the deepwater pipe-laying process,which can lead to elliptical buckling and even deterioration failure.For the safety of pipe-laying operation,available formulas for the pipe stability are established on the basis of the assumption of uniform deformation along the tube length and symmetrical buckling.This method can predict the nonlinear response of elliptical collapse of steel circular tubes for different ratios of diameter to thickness（D/t）under pure bending or combined bending and external pressure.In these formulas,the strain-displacement relationship is deduced from the nonlinear ring theory,and the Ramberg-Osgood constitutive model is applied to simulate the inelastic material behavior.Meanwhile,the principle of virtual work is adopted to derive the equilibrium equations.A set of equations is solved by the Newton-Raphson method,and the iterative scheme contains nested iteration for the constitutive relation.In order to check the effectiveness of this theoretical method,illustrative examples are presented in this paper.Besides,the numerical simulation is carried out by use of ANSYS.A comparison of the results shows that the theoretical method can provide reasonable prediction for engineering practice.

Laboratory investigation into the oil diffusion from submarine pipeline under water flow

A physical model test has been conducted to study the oil diffusion from the submarine pipeline under water flow.The crude oil in the flume is spilled from a leakage point of the pipeline and diffused from the seabed to the surface. By the non-contact optical measuring technology, an image acquisition and data analysis system is designed to explore the spilled mechanism and characteristic. The oil trajectory, velocity and the rising time to the surface are obtained through this system. The influence of the water flow and the spilled discharge on the behavior of the spilled oil are analyzed from both qualitative and quantitative perspectives. The sensitivity study of the characteristic physical quantities to various factors are presented afterward. The spilled oil under water is mainly distributed in the form of the scattered particles with different sizes. The rising process of the oil can be divided into three stages: full, dispersion and aggregation period. The spilled discharge is the primary factor affecting the rising time of the oil particles. In the rising process of the oil particles, the vertical velocity of the oil is mainly affected by the spilled discharge, and the transverse velocity is more dependent on the water velocity. The deviation of the transverse oil velocity is much larger than that of the rising time and the vertical oil velocity. The study can provide a theoretical reference for the prediction system of oil spill emergency.

Discussion on applying an analytical method to optimize the anti-freeze design parameters for underground water pipelines in seasonally frozen areas

Adopting the quasi-three-dimensional （Quasi-3D） numerical method to optimize the anti-freeze design parameters of an underground pipeline usually involves heavy numerical calculations. Here, the fitting formulae between the safe con-veyance distance （SCD） of a water pipeline and six influencing factors are established based on the lowest water temper-ature （LWT） along the pipeline axis direction. With reference to the current widely used anti-freeze design approaches for underground pipelines in seasonally frozen areas, this paper first analyzes the feasibility of applying the maximum frozen penetration （MFP） instead of the mean annual ground surface temperature （MAGST） and soil water content （SWC） to calculate the SCD. The results show that the SCD depends on the buried depth if the MFP is fixed and the variation of the MAGST and SWC combination does not significantly change the SCD. A comprehensive formula for the SCD is estab-lished based on the relationships between the SCD and several primary influencing factors and the interaction among them. This formula involves five easy-to-access parameters： the MFP, buried depth, pipeline diameter, flow velocity, and inlet water temperature. A comparison between the analytical method and the numerical results based on the Quasi-3D method indicates that the two methods are in good agreement overall. The analytic method can be used to optimize the anti-freeze design parameters of underground water pipelines in seasonally frozen areas under the condition of a 1.5 safety coefficient.

Corrosion Pattern of Pipeline Steel in Petroleum Pipeline Water in the Presence of Biomas Derived Extracts of <i>Brassica oleracea</i>and <i>Citrus paradise</i>Mesocarp

Corrosion inhibition characteristics of two biomass derived extracts from outer leaves of Brassica oleracea (BO) and Citrus paradise mesocarps (CPM) on pipeline steel were investigated using modified gravimetric method at ambient temperature (28 ± °C). Petroleum pipeline water was used to simulate a pseudo-anaerobic corrosion cell. The result obtained showed that corrosion was a continuous process in the closed system, while BO and CPM showed near equivalence corrosion inhibition efficiency of 91.45% and 89.44% respectively at the concentrations studied. The thermodynamic data suggests inhibition to be through molecular adsorption on metal surface.

Experimental investigation of hydrate formation in water-dominated pipeline and its influential factors

Blockage in water-dominated flow pipelines due to hydrate reformation has been suggested as a potential safety issue during the hydrate production.In this work,flow velocity-dependent hydrate formation features are investigated in a fluid circulation system with a total length of 39 m.A 9-m section pipe is transparent consisted of two complete rectangular loops.By means of pressurization with gas-saturated water,the system can gradually reach the equilibrium conditions.The result shows that the hydrates are delayed to appear as floccules or thin films covering the methane bubbles.When the circulation velocity is below 750 rpm,hydrate is finally deposited as a“hydrate bed”at upmost of inner wall,narrowing the flow channel of the pipeline.Nevertheless,no plugging is observed during all the experimental runs.The five stages of hydrate deposition are proposed based on the experimental results.It is also revealed that a higher driving pressure is needed at a lower flow rate.The driving force of hydrate formation from gas and water obtained by melting hydrate is higher than that from fresh water with no previous hydrate history.The authors hope that this work will be beneficial for the flow assurance of the following oceanic field hydrate recovery trials.

Research Progress of Buckling Propagation Experiment of Deep-Water Pipelines

In recent years, the extraction of fossil resources, especially oil and gas in deep and ultra-deep water areas has been playing a more important role and been paid more attention to. For this reason, the working depth of submarine pipelines, which are used for the transportation of oil and gas, has been increasing sharply. As the main failure pattern of deep-water pipelines, buckling and its propagation problem have drawn more attention of many research institutions and engineering units around the world. Based on the existing research, the summary of experiments and their outcomes of deep-water pipeline buckling failure is made in this paper. Research status and developing prospects of the experiments of buckling propagation and buckle arrestor are discussed in detail.

Investigation of Soil Aggressiveness towards Underground Fuel Storage Tanks and Water Pipelines in Parts of Bayelsa State, Southern Nigeria

Structural failure of buried cast/ductile iron water mains and tanks due to corrosion attacks manifests in leaks and is common in most cities throughout Nigeria. The appropriate corrective action, which aims to restore pipe/tank integrity is usually based on proper understanding of the degree of corrosiveness of the soil. In an attempt to determine the potential corrosiveness of the soil to buried metallic structures in Bayelsa State, surface geoelectrical sounding was carried out. Twenty-five Schlumberger Vertical Electrical Soundings (VES) was carried out in the freshwater and meander belt geomorphic zone and the salt water mangrove swamp and estuary complex of the state using a maximum current electrode separation ranging from 200 - 400 m. The data obtained was interpreted by computer iterative modeling using a 1D inversion technique software (1X1D, Interpex, USA). The results show a high degree of heterogeneity, both laterally and vertically, which is typical of a complex depositional environment. Generally, the sub-soil condition within the expected depth of installation of water mains and storage tanks (0 - 10 m) is slightly or moderately aggressive (effective aggressivity) in the freshwater and meander belt geomorphic zone but is very strongly aggressive in the salt water mangrove swamp and estuary complex. Corrosion cells which may lead to significant corrosion failures may occur in the vicinities of strongly aggressive stations. This poses a significant corrosion risk to metallic water pipes and storage tanks. Current day design should therefore either mandate the use of a non-metallic piping product (water mains) or cathodic protection system. Prediction of potential corrosiveness of a soil and thus the application of proper corrosion control measures will not only protect the environment from spillages but will also avert cost of repair, clean-up and replacement.

Landslide Zoning in Amir-Almoemenin (AS) Water Supply Pipeline Complex, North Khorasan

Landslide term is used for all mass movements on slopes, including falling, overturns and flow debris. Using the potential landslide hazard zonation, areas with high potential of landslide hazard can be detected and so prevent the landslide occurrence with providing appropriate solutions. In this study, the landslide hazard zonation along the water transmission lines of the Amir-Almomenin (AS) water supply complex has been done. Studied area is located at the western part of the Northern Khorasan (Bojnord). Study procedure includes the general geology survey, recognition of the most important effective parameters on the landslide phenomena (such as slope, lithology, faults and streams) and has been evaluated as basic maps. Then, each layer was validated based on the importance of the effective factors using the maps weighting method in ArcGis software. Finally, the studied area was zoned based on the landslide potential using the overlapping of the various layers. Final zonation map shows that the North, Northwestern and Median parts of the studied area have the highest landslide potential. These areas are included of Marl and red Marl and to some extend loss deposits with slopes between 14 to more of 50 degrees. Seemingly, faults (due to low occurrence) and streams (due to drought) have lower effect on the landslide potential. However, the degree of the slope and type of lithology are the most important parameters on the landslide potential, respectively.

Analysis of Water Pipeline Breaks

This study explores the arrivals of water pipeline break failures. The aim is to assist the facility manager in the decision making process. Based on characteristics of the data set ranging from 2011 to 2014, two steps of analysis were presented in the paper. This first step is the analysis of partially complete data set (2011 data). The 2-sample KS test is adopted to check the similarity between this data set and the entire data set with no underlying distribution implied. In order to conduct the reliability analysis, the Weibull distribution is adopted to evaluate the data. For annual data set, the 2-parameter Weibull distribution fits data sets pretty well. The shape parameters are a little greater than 1, indicating a slightly increasing arrival rate of such failures. For the entire data set, the 3-parameter Weibull tends to fit the data better than the 2-parameter Weibull. The shape parameter is well above 1, indicating an increasing arrival rate of the failures. To eliminate the impact of missing points for the 2011 data set, data from 2012 to 2014 were also considered as a new set, the Weibull distribution generated a decent fitting. The shape parameter is a little greater than 1. Therefore, there is a slightly increasing arrival rate of those pipeline failures. Results from this study provide decision makers valuable information in terms of whether additional efforts shall be made to enhance the system’s performance in order to reduce the failure rate.

Sendai Water Pipeline Response to the 2011 Tohoku Earthquake

Damage caused by the 2011 Tohoku Earthquake （Mw 9.0） to transmission and distribution pipelines in Sendai City is summarized. The locations of the pipeline repairs are discussed relative to earthquake intensity, geomorphologic conditions and landform change in the developed areas of hilly land. Repair rate （repairs/km） is summarized according to pipe material and presence or absence of artificial landform change. The following findings were obtained： （1） More than 80% of the repairs took place in pipelines installed in higher lands such as hill and terrace areas consisting of hard soils; （2） Nearly all the pipe repairlocations in hill areas are where landform change was made through land development tor residential purposes over me past several decades; （3） The aforementioned repair rate was more than 3.6 times than that of other lowland areas where no landform change occurred. The heaviest concentrations of pipe repairs of vinyl chloride pipes and ductile iron pipes were observed within the boundary area between cutting and filling, having a thickness between -2.5 m and 2.5 m. Approximately 78% of the all pipe repairs occurred outside of areas where severe ground failures took place. A mechanism of pipe damage in the areas free of severe ground failure was discussed.

Economical and Environmental Effects of Pressure Reducer Valve Substituting by Small Hydro Power-Plants in Gravity Water Transmission Pipelines in Iran

In this work, historical background of power generation by small hydro-power plants across the world and specially across the Iran with emphasis on small hydro-power plant utilization as recovery turbine in water transmission pipeline have been attended firstly, and then, three water transmission pipelines from Chah-nemie to Zahedan city, Shirindare dam to Bojnord city and Mokhtaran desert to Birjand city in Iran have been studied as case study samples. According to the sample pipeline characteristics and pipeline topography, reachable energy have been estimated; in the next step, pay attending to reachable energy, initial investment cost, total benefit of operating period, benefit to cost ratio and other economical parameters for small hydro-power plants in case study pipelines have been presented and generated power cost of the same amount via other resources compared to the hydro-power cost. At the end, in agreement with environmental advantages of small hydro-power plants, the methods of generated power utilization, proper solution for optimization of reachable energy in water transmission pipeline and substitution of pressure reducing valve by small hydro-power plant in the pipelines as a major solution for energy recovering in water pipelines have been proposed.