Retroerosion in a TBG Gas Pipeline Crossing and its Rehabilitation

2019 ◽  
Author(s):  
Cesar Augusto Costa ◽  
Walter Schultz Neto ◽  
Thiago Wichrestink Zozula
Keyword(s):  
Process Analysis ◽  
Temporal Trends ◽  
Gas Pipeline ◽  
Aerial Photographs ◽  
Erosion Process ◽  
Buried Pipe ◽  
Base Level ◽  
Channel Erosion ◽  
Equilibrium Profile ◽  
Pipeline Crossing

Abstract This Paper presents a case study of the Jardim Novo Maracanã stream situated in Campinas, São Paulo, in which recent streambed modifications were characterized, aiming to define the rates and the potential erosions along the channel alignment of which have Bolivia-Brazil Gas Pipeline crossing. Its presents the erosion process analysis and mitigation concepts aimed at the pipeline and fiber optic cables facilities integrity, as well as to indicate the design issues, considering the streambed deepening in this watershed. For this, satellite images and aerial photographs were collected in different periods, soil and subsoil surveys were performed, information on rainfall and watershed characteristics was analyzed, as well as hydrological and hydrotechnical studies were developed. These studies included geotechnical channel and banks analyzes, the spatial and temporal trends of the fluvial geomorphology evolution and the infrastructures safety conditions analysis. It was concluded that a new channel erosion process occurred after the streambed was filled by recent sediments. This process is associated with an increase floods magnitude, the slopes occupation intensification with the county urbanization and the streambed conditions changes, from an alignment sinuous to rectilinear and from a shallow to deeper channel. Once initiated, the channel erosion process maintained its retroerosion, i.e. its “headcutting” trend, deepening its equilibrium profile to its stratigraphic base level, located about 5.0 m below the 2014 stream bottom, in the pipeline cross section. Alternative concepts for the infrastructure integrity rehabilitation in these new morphological-fluvial conditions were also developed and dimensioned. Among these, the rectangular culverts alternative was adopted. They support a landfill at the crossing with the buried pipe and have to 100-year return period peak flows capacity.

Research on Aseismatic Measures of Gas Pipeline Crossing a Fault for Strain-Based Design

2009 ◽  
Author(s):  
Xiaoting Gu ◽  
Hong Zhang
Keyword(s):  
Design Method ◽  
Large Diameter ◽  
Strain Analysis ◽  
Gas Pipeline ◽  
Analysis Model ◽  
Buried Pipe ◽  
Size And Shape ◽  
Buried Gas Pipeline ◽  
Pipeline Design ◽  
Pipeline Crossing

There are a lot of researches on qualitative aseismatic measures for buried gas pipeline crossing movable faults. But a few of them are quantitative, especially in the size and shape of the trench. In this paper, based on strain-based pipeline design method and finite element method, a new strain analysis model for buried large diameter gas pipeline is presented that deals quantitatively with the pipeline strain influencing factors, such as the size and shape of the trench, buried pipe depth, crossing angle between pipeline and fault, pipe diameter and wall thickness, mechanical properties of original soil and back fill soil, inner pipeline pressure. In this model, the pipeline is simulated by pipe element and elbow element, soil-pipe interaction is reduced to 3 dimensional soil spring. By means of FEM software ABAQUS, detail analysis is performed for a real design case of pipeline crossing a movable fault in the second west-east gas pipeline project of China, and optimized pipeline crossing fault scheme is proposed which can minimize the pipeline strain and limit it in allowable value.

Stress Analysis and Strength Checking for High Pressure Gas Pipeline in the Earthquake Rupture Area

2013 ◽  
Vol 470 ◽  
pp. 866-870
Author(s):  
Wei He ◽  
Yan Dong Liu ◽  
Guo Xing Wang
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Stress Analysis ◽  
Gas Pipeline ◽  
Earthquake Rupture ◽  
Rupture Area ◽  
Pipeline Crossing ◽  
The Way

Based on the actual project example of high pressure gas pipeline crossing earthquake rupture area, the paper shows and explains the way to make stress analysis and strength checking calculation for the high pressure gas pipeline in the earthquake rupture area by the method of finite element.

Strain Analysis of Oil and Gas Pipeline with Dents Based on ILI Data

2016 ◽  
Vol 853 ◽  
pp. 372-376
Author(s):  
Zheng Qiang Lei ◽  
Jian Chen ◽  
Fu Xiang Wang ◽  
Ting Wang ◽  
Li Jian Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Oil And Gas ◽  
Strain Analysis ◽  
Gas Pipeline ◽  
Safe Operation ◽  
Buried Pipe ◽  
Strain Calculation ◽  
Acceptable Range ◽  
Integrity Analysis

Dents in an oil and gas pipeline can be detected by In-line-Inspection (ILI), and structure integrity analysis of the pipe with theses reported dents is important for the safe operation. Strain analysis of the dented pipe is a way of fine assessment and ASME B31.8 has established the strain assessment code and its acceptable range. However, the method of strain assessment is rarely used due to the difficulty of strain calculation for a buried pipe. In this study, features of ILI data are investigated to elaborate the necessary of filtering analysis for strain analysis of the dent with ILI data. Then typical filtering methods are used to smooth the ILI data, and strain analysis are carried out with the smoothed data to study the practicability of strain assessment. Profile and strain of a dent in D813 pipe were obtained by Finite Element Method (FEM). Then different filtering methods were used to smooth the simulated ILI data of the dent which were selected from FEM profile. Strain of the dent were also calculated by smoothed data with the latest ASME B31.8 code, and compared with it from FEM at last to prove the feasibility and validity of the filtering methods with ASME B31.8 code.

scholarly journals SCOUR AROUND MODEL PIPELINES DUE TO WAVE ACTION

1976 ◽  
Vol 1 (15) ◽  
pp. 94 ◽  
Author(s):  
John B. Herbich
Keyword(s):  
Scale Effects ◽  
Initial Slope ◽  
Extensive Literature ◽  
Ocean Bottom ◽  
Buried Pipe ◽  
Offshore Pipelines ◽  
Size Number ◽  
Equilibrium Profiles ◽  
Equilibrium Profile ◽  
Pipeline Failures

The size, number and application of offshore pipelines are steadily increasing. At the same time, the incidence of reported pipeline failures is also increasing. There appear to be several reasons for these failures, and they can be placed in two basic categories: 1. inadequate cover, and 2. low "specific gravity" of the pipeline. Under the first category the depth of burial may be insufficient, the type of burial material may be inferior to the material alongside the trench, or the compaction of cover material may be inadequate. Under the second category the pipe may actually float up to the surface from the ocean bottom as material around the buried pipe liquifies. An extensive literature search revealed that many studies were conducted by Meyers (1936), Waters (1939), Johnson (1940), W.E.S. (1940), Rector (1954), Wiegel, et al (1954), Saville (1957), Iwagaki and Noda (1962), Nayak (1972), Noda (1972), and Earattupuzha (1974). In general, two types of "equilibrium profiles" were developed in the laboratory flumes, the "ordinary" and the "storm" (sometimes referred to as summer and winter profiles). Despite numerous previous investigations, knowledge of the "scale effects" involved in equilibrium beach profiles is inadequate. Many authors have analyzed model data without stating the relation between model and prototype dimensions. In addition, many have claimed certain phenomena observed in the model to be independent of initial slope. An extensive laboratory study was conducted to evaluate the development of underwater bars and scour patterns with the pipeline buried at various depths below the ocean bottom. Pictures of the beach profile were taken at specific time intervals through the glass wall of the wave tank. Attempts were made to correlate equilibrium profile geometric quantities, such as depth of offshore bar, scour depth and berm height with the wave characteristics. Qualitative agreement between laboratory and natural beach profiles were demonstrated by trial and error fitting of one to the other.

Differentiating Pleistocene tectonically driven and climate-related fluvial incision: the Sanggan River, Datong Basin, North China

2006 ◽  
Vol 143 (3) ◽  
pp. 393-410 ◽  
Author(s):  
CHENG SHAO-PING ◽  
LI CHUAN-YOU ◽  
YANG GUI-ZHI ◽  
ZHOU SHI-WEI
Keyword(s):  
North China ◽  
Profile Analysis ◽  
High Water ◽  
Water Levels ◽  
Humid Climate ◽  
Datong Basin ◽  
Base Level ◽  
Fluvial Incision ◽  
Equilibrium Profile ◽  
Basaltic Flow

The Sanggan River is an alluvial river flowing through a graben basin system of the northern Shanxi Rift Zone, North China. During Pleistocene times, the river reach in the Datong Basin was affected successively by various external variables, such as invasion by basaltic flow, along-valley faulting and climatic change. Therefore, it provides excellent constraints for differentiating tectonically driven and climate-related fluvial incision in the context of tectonic subsidence. Based on equilibrium profile analysis, K–Ar dating of basalts (0.74–0.41 Ma), studies of the river terrace and of stream action history, we present a conceptual model for differentiating fault-driven and climate-related fluvial incision by the river. The results show that fluvial incision induced by tectonic lowering of the base-level due to along-valley movement on the Sanggan River fault is equal to fault displacement. The amount of post-basalt fluvial incision of the reach upstream from the lava dam is 23 to 25 m, of which the fault-driven and climate-related incisions are 15 m and 8 to 10 m, respectively, the former predominating over the latter. The total amount of incision in the lava dam reach is 40 to 47 m, of which the fault-driven and climate-related incisions are 10 m and 30–37 m, respectively; here the latter is predominant over the former. Since 0.41 ± 0.10 Ma, the rate of fluvial incision of the lava dam reach of the river has reached 98–115 m/Ma, which is 1.5–2 times as great as those of the reaches upstream and downstream from the lava dam. The higher rate of fluvial incision can be attributed to high water levels supplied by the onset and maintenance of backwater conditions in the reach upstream from the lava dam, due to the long period of warm and humid climate in this region. Plucking, abrasion and knickpoint migration appear to be the primary erosional processes in the lava dam reach.

Erosion process analysis of die-casting inserts for magnesium alloy components

2013 ◽  
Vol 33 ◽  
pp. 457-464 ◽  
Author(s):  
Li-feng Hou ◽  
Ying-hui Wei ◽  
Yong-gang Li ◽  
Bao-sheng Liu ◽  
Hua-yun Du ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Process Analysis ◽  
Die Casting ◽  
Erosion Process

scholarly journals Soil Erosion and Controls in the Slope-Gully System of the Loess Plateau of China: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Bingbing Zhu ◽  
Zhengchao Zhou ◽  
Zhanbin Li
Keyword(s):  
Soil Erosion ◽  
Loess Plateau ◽  
Overland Flow ◽  
Vegetation Pattern ◽  
Sediment Source ◽  
The Loess Plateau ◽  
Erosion Process ◽  
Slope Length ◽  
Base Level ◽  
Erosion Processes

The Loess Plateau has long been suffering from serious soil erosion of which erosion from the slope-gully system is now dominant. The slope-gully system is characterized with distinctive erosion distribution zones consisting of inner and inter gully areas wherein erosion patterns spatially vary, acting as both sediment source and the dominant sediment and water transport mechanism. In this paper, a substantial body of research is reviewed concentrating on the soil erosion processes and control practices in the slope-gully system. The inner gully area is identified as the main sediment source while runoff and sediment from the inter-gully upland is found to significantly affect down slope erosion processes. Correspondingly, the protective vegetation pattern and coverage should be strategically designed for different erosion zones with an emphasis on the critical vegetation cover and pattern to reduce sediment yield of the whole slope-gully system. Check-dam could change the base level of erosion and reduce the slope length of the gully side, which will further decrease the possibility and magnitude of gravity erosion. We concluded that understanding the erosion processes and implementing erosion practices for the slope-gully system are of importance and require more research efforts that emphasize: 1) the influence of upland runoff on erosion processes at downslope; 2) the relationship between hydraulic characteristics of overland flow and erosion process at a slope-gully system scale; 3) physical mechanisms of different vegetation patterns on the slope-gully erosion process.

scholarly journals Seismic expression of depositional elements associated with a strongly progradational shelf margin: northern Santos Basin, southeastern Brazil

2016 ◽  
Vol 46 (4) ◽  
pp. 585-603 ◽  
Author(s):  
Fábio Berton1* ◽  
◽  
Fernando Farias Vesely
Keyword(s):  
Mass Transport ◽  
Progressive Increase ◽  
Seismic Facies ◽  
Southeastern Brazil ◽  
Submarine Channels ◽  
Base Level ◽  
Equilibrium Profile ◽  
Mass Transport Deposits ◽  
Shelf Margin ◽  
Depositional Elements

ABSTRACT: Seismic facies analysis and seismic geomorphology are important tools for the analysis of depositional elements in subsurface. This paper aimed to investigate the character and genesis of depositional elements and erosive features associated with an Eocene progradational shelf margin in northern Santos Basin. Identified seismic facies are interpreted as shelf-margin deltas/shoreface deposits, tangential (oblique) clinoforms, sigmoidal clinoforms, topset reflectors, mass-transport deposits and turbidites. These facies are grouped into four associations representing periods of relatively constant environmental conditions. Association 1 is composed of shelf-margin deltas/shoreface deposits, tangential clinoforms and extensive sand-rich turbidites disposed as submarine channels and frontal splays. A progressive increase in clinoform angle within this association has been identified, culminating in high-relief sigmoidal clinoforms with less voluminous turbidites of facies association 2. Association 3 is composed by subparallel to divergent topset reflectors, interpreted as continental to shelfal deposits placed during base-level rises. These are always truncated basinward by slump scars, formed as a consequence of sediment overload at the shelf margin during aggradations. Association 4 is composed of sigmoidal clinoforms, mass-transport deposits and turbidites. Early clinoforms are steeper as a consequence of the topography of the slump scars. Subsequently, dip angles become progressively gentler as the system approach to the equilibrium profile. The steep physiography was favorable for canyon incision, which played an important role in turbidite deposition. Mass-transport deposits, formed subsequent to slope collapse, are composed of mud-rich diamictites, and show strong internal deformation.

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