scholarly journals 2D numerical study of wave and current-induced oscillatory non-cohesive soil liquefaction around a partially buried pipeline in a trench

2017 ◽  
Vol 135 ◽  
pp. 39-51 ◽  
Author(s):  
Lunliang Duan ◽  
Chencong Liao ◽  
Dongsheng Jeng ◽  
Linya Chen
Keyword(s):  
Numerical Study ◽  
Cohesive Soil ◽  
Soil Liquefaction ◽  
Buried Pipeline

scholarly journals Performance Study of Buried Pipelines under Static Loads

2022 ◽  
Vol 8 (1) ◽  
pp. 1-23
Author(s):  
Mahdi J. Alanazi ◽  
Yang Qinghua ◽  
Khalil Al-Bukhaiti
Keyword(s):  
Sandy Soil ◽  
Manufacturing Process ◽  
Computer Aided Design ◽  
Research Study ◽  
Numerical Study ◽  
Pipeline Steel ◽  
Cohesive Soil ◽  
Slope Instability ◽  
Buried Pipelines ◽  
Static Loads

The possibility of servicing lifelines such as highways, railways, pipelines, and tunnels is of great social importance. The characteristic that separates the buried pipeline from other structures is that its dimensions are very long compared to its other dimensions. Ground vibrations caused by earthquakes, construction activities, traffic, explosions, and machinery can damage these structures. Lifeline integrity can be compromised in two ways: (1) direct damage due to excessive dynamic loading of the lifeline, and (2) indirect damage due to soil failures such as liquefaction, slope instability, and differential settlements. 3D printing (also known as additive manufacturing) is an advanced manufacturing process that can automatically produce complex geometric shapes from a 3D computer-aided design model without tools, molds, or fixtures. This automated manufacturing process has been applied in diverse industries today because it can revolutionize the construction industry with expected benefits. This research study on the performance of buried pipelines under static loads to the structure's safety against the possible development of progressive failure. This research study includes a numerical study, where it was studied many parameters to value the performance of the pipeline. The parameters are (a) the material of the pipeline (steel, traditional concrete, and 3D concrete printed), (b) the thickness of the pipeline (20, 30, and 40 mm), and (c) soil type (moist sandy soil, saturated sandy soil, moist cohesive soil, and saturated cohesive soil). Different results were obtained depending on the type of soil where all pipelines materials' behavior was similar in the case of moist soil. Doi: 10.28991/CEJ-2022-08-01-01 Full Text: PDF

scholarly journals Numerical Study of Wave- and Current-Induced Oscillatory Seabed Response near a Fully Buried Subsea Pipeline

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Lunliang Duan ◽  
Meiling Fan ◽  
Duoyin Wang ◽  
Caixia Meng ◽  
Lei Xing
Keyword(s):  
Laboratory Experiments ◽  
Present Model ◽  
Numerical Study ◽  
Coupled Model ◽  
Navier Stokes ◽  
Comsol Multiphysics ◽  
Buried Pipeline ◽  
Subsea Pipeline ◽  
Current Interaction ◽  
Fluid Characteristics

To investigate the wave- and current-induced seabed response near a fully buried subsea pipeline, a two-dimensional coupled model for fluid-seabed-pipeline interaction (FSPI-2D) is developed within the framework of COMSOL multiphysics. Different from previous studies, both the wave-current interaction and the nonlinear pipeline-soil contacts are considered in the present model. In this paper, Biot’s consolidation mode is used to govern the fluid-induced seabed response, and combined Reynolds averaged Navier–Stokes (RANS) equation with the k-ε turbulence model is employed to simulate the fluid propagation. Meanwhile, the pipeline is treated as a linear elasticity. Firstly, the effectiveness of the new model is verified by laboratory experiments from previous reports. Then, the numerical model is employed to examine the effects of nonlinear pipeline-seabed contacts and fluid characteristics on the seabed response around the structure. Finally, the momentary liquefaction near the fully buried pipeline is studied based on the 2D coupled model.

Suction Bucket Foundations for Wind Energy Turbines: A Numerical Study With FEM

2016 ◽  
Author(s):  
Paola Dutto ◽  
Matthias Baessler ◽  
Peter Geissler
Keyword(s):  
Wind Energy ◽  
Pore Water Pressure ◽  
Numerical Study ◽  
Water Pressure ◽  
Soil Liquefaction ◽  
Offshore Wind ◽  
Offshore Wind Energy ◽  
Soil Behavior ◽  
Suitable Alternative ◽  
Key Aspects

Suction Bucket Jackets (SBJ) are found as a suitable alternative to driven piles for the support of jacket or tripod foundations for offshore wind energy converters. Offshore wind energy turbines are characterized by a small self weight and they can be subjected to different load combinations. The work presented here aims to show the numerical investigation on the behavior of suction bucket foundations under different kind of loads as well as load combinations. In order to do so, a suitable numerical model is much needed. The theoretical basis of the model lies on the Swansea formulation of Biots equations of dynamic poroelasticity combined with a constitutive model that reproduces key aspects of cyclic soil behavior in the frame of the theory of generalized plasticity. An adequate FE formulation, the representation of appropriate soil-structure interfaces and the computational efficiency are key aspects in order to successfully model such complex systems. The 3D numerical simulation allows a special insight into the fundamental behavior of the founding of Suction Bucket Jackets such as the evolution of the pore water pressure or the occurrence of the so called soil liquefaction.

scholarly journals Experimental and Numerical Study on the Strain Behavior of Buried Pipelines Subjected to an Impact Load

2019 ◽  
Vol 9 (16) ◽  
pp. 3284 ◽  
Author(s):  
Feifei Dong ◽  
Xuemeng Bie ◽  
Jiangping Tian ◽  
Xiangdong Xie ◽  
GuoFeng Du
Keyword(s):  
Finite Element ◽  
Impact Load ◽  
Numerical Study ◽  
Scale Model ◽  
Peak Strain ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Strain Behavior ◽  
Geological Conditions ◽  
The Impact

Long-distance oil and gas pipelines are inevitably impacted by rockfalls during geologic hazards such as mud-rock flow and landslides, which have a serious effect on the safe operation of pipelines. In view of this, an experimental and numerical study on the strain behavior of buried pipelines under the impact load of rockfall was developed. The impact load exerted on the soil, and the strains of buried pipeline caused by the impact load were theoretically derived. A scale model experiment was conducted using a self-designed soil-box to simulate the complex geological conditions of the buried pipeline. The simulation model of hammer–soil–pipeline was established to investigate the dynamic response of the buried pipeline. Based on the theoretical, experimental, and finite element analysis (FEA) results, the overall strain behavior of the buried pipeline was obtained and the effects of parameters on the strain developments of the pipelines were analyzed. Research results show that the theoretical calculation results of the impact load and the peak strain were in good agreement with the experimental and FEA results, which indicates that the mathematical formula and the finite element models are accurate for the prediction of pipeline response under the impact load. In addition, decreasing the diameter, as well as increasing the wall thickness of the pipeline and the buried depth above the pipeline, could improve the ability of the pipeline to resist the impact load. These results could provide a reference for seismic design of pipelines in engineering.

Numerical Analysis of Floatation Response of Buried Pipeline in Liquefied Soil

2014 ◽  
Vol 580-583 ◽  
pp. 791-796
Author(s):  
Su Nan Deng ◽  
Wen Tao Peng ◽  
Jun Qi Lin
Keyword(s):  
Numerical Analysis ◽  
Elastic Foundation ◽  
Axial Force ◽  
Soil Property ◽  
Soil Liquefaction ◽  
Influential Factors ◽  
Beam Model ◽  
Buried Pipeline ◽  
Calculation Results ◽  
Homogeneous Soil

In this paper, the formulae are deduced for the floatation response of pipeline buried in liquefied soil. The beam model based on the theory of beam on elastic foundation is used for the pipeline buried in non-liquefied and liquefied soil. The soil property is nonlinear, the floating force induced by the soil liquefaction is related to the position of pipeline, is nonlinear also. For the convenience and simplification of analysis, the nonlinear increment element method was used and lots of numerical analysis was conducted, including: the floatation response of pipeline buried in homogeneous soil, the floatation response of pipeline buried in non-homogeneous soil, and the floatation response of pipeline buried in discontinuous liquefied area. The influential factors on the floatation response of buried pipeline buried in liquefied soil including spring stiff of liquefied soil, the initial deformation, the length of liquefied area, the axial force acting on the pipeline, the material of pipeline, and the diameter of pipeline. The calculation results of discontinuous liquefied area draw a significant conclusion that for a long liquefied area, to make the soil non-liquefied in the middle of liquefied area may decrease the length of liquefied area and reduce the flotation displacement of pipeline greatly.

scholarly journals Coupling Interaction of Surrounding Soil-Buried Pipeline and Additional Stress in Subsidence Soil

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yahong Ding ◽  
Heng Yang ◽  
Ping Xu ◽  
Minxia Zhang ◽  
Zhenguo Hou
Keyword(s):  
Deformation Zone ◽  
Cohesive Soil ◽  
Test System ◽  
Additional Stress ◽  
Burial Depth ◽  
Buried Pipeline ◽  
Research Results ◽  
Soil Subsidence ◽  
Cohesion Less Soil ◽  
Surrounding Soil

In the process of underground resource exploitation, the induced surface subsidence easily leads to the deformation and failure of buried pipeline. And in the process of soil subsidence, the complex interaction between buried pipeline and surrounding soil occurs, which leads to deformation and additional stress in buried pipeline. In this paper, a laboratory test system is designed and developed to analyze the influence of buried depth, cohesion of soil, and angle of internal friction on stress, in order to obtain the deformation mechanism of pipe-soil and the pressure around the pipe and the distribution of additional axial stress along the pipeline. The research results show that in the process of subsidence, the synergistic deformation between the pipe and soil at both ends of the subsidence area is maintained, while there is a compressive nonsynergistic deformation zone in the soil at the top of the pipe, and the deformation zone in the cohesion-less soil and the cohesive soil presents a spire shape and an arch shape, respectively. Areas of maximum additional tensile and compressive stresses occur in the area of maximum curvature and the central position. In addition, the smaller the burial depth, the earlier the unloading phenomenon occurs; and the additional stress in buried pipe in cohesion-less soil is significantly less than that in cohesive soil, and the unloading phenomenon occurs earlier. The research results provide the basis for disaster prevention of buried petroleum transmission pipeline in subsidence process.

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