scholarly journals An Energy Solution for Predicting Buried Pipeline Response Induced by Tunneling Based on a Uniform Ground Movement Model

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Xin Shi ◽  
Chuanxin Rong ◽  
Hua Cheng ◽  
Linzhao Cui ◽  
Jie Kong
Keyword(s):  
Ground Movement ◽  
Energy Solution ◽  
Additional Stress ◽  
Buried Pipeline ◽  
Movement Model ◽  
Total Potential ◽  
Calculation Results ◽  
Pasternak Model ◽  
Stress And Deformation ◽  
Final Settlement

The construction of shield tunnels inevitably causes displacement of the surrounding soil and additional stress and deformation of the buried pipeline. An energy solution for predicting the deformation of buried pipelines caused by tunneling is proposed in this study. First, based on the uniform ground movement model, the interval of the free displacement field of soil around the pipeline induced by tunneling is calculated. Then, we use the Pasternak model to establish the total potential energy equation of the tunnel-soil-pipeline interaction. The final settlement interval of the pipeline is obtained by solving the numerical calculation program with MATLAB. The calculation results of the energy solution are compared with the results of the centrifugal test and the reported theoretical solutions of Winkler and Pasternak, and then the applicability of the solution for predicting the pipeline response under different geotechnical conditions is verified. Combined with an engineering case, the energy method calculation results, numerical simulation results, and measured results are compared to obtain the most unfavorable position of the pipeline caused by tunneling. At the end of this study, the application steps of the proposed method in actual construction are summarized. These steps are used to predict pipeline response in order to take protective measures.

scholarly journals A Simplified Analysis Method for the Deformation Response of an Existing Tunnel to Ground Surcharge Based on the Pasternak Model

2021 ◽  
Vol 11 (7) ◽  
pp. 3255
Author(s):  
Zheng Wei ◽  
Yusheng Jiang
Keyword(s):  
Longitudinal Displacement ◽  
Maximum Displacement ◽  
Deformation Response ◽  
Reaction Coefficient ◽  
Element Simulation ◽  
Tunnel Model ◽  
Calculation Results ◽  
Pasternak Model ◽  
Boussinesq Solution ◽  
Euler Bernoulli Beam

Surface surcharge changes the existing equilibrium stress field of the stratum and adversely affects the existing tunnel. This paper presents a simplified analytical solution for calculating the longitudinal displacement of existing tunnels that are subjected to adjacent surcharge loading. Based on the Boussinesq solution, the distribution of the additional load matrix caused by the surface surcharge on the existing tunnel was obtained. A Euler–Bernoulli beam with a Pasternak foundation was used as a simplified model for tunnel stress analysis. Using the corrected reaction coefficient of the foundation bed, the differential equation of tunnel deformation was established, and the solution matrix of the longitudinal displacement of the tunnel was obtained by using the finite difference method. The reliability and applicability of the proposed method were verified by comparing the results with finite element simulation results, field test data, and the calculation results of three simplified elastic analysis methods with different foundation bed coefficients. On this basis, the parameters of the load–tunnel model were analyzed, and the effects of the buried depth, the size of the load, the relative positions of the load and the tunnel, and the relative stiffness of the tunnel soil on the maximum displacement of the existing tunnel were calculated. An empirical formula is proposed for calculating the maximum longitudinal displacement of the existing tunnel subjected to surface surcharge. The findings of this research can provide a basis for the theoretical verification of the deformation response of an existing tunnel subjected to adjacent surface surcharge.

scholarly journals Additional Stress on a Buried Pipeline under the Influence of Coal Mining Subsidence

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Ping Xu ◽  
Minxia Zhang ◽  
Zhibin Lin ◽  
Zhengzheng Cao ◽  
Xu Chang
Keyword(s):  
Coal Mining ◽  
Surface Deformation ◽  
Analytical Calculation ◽  
Mining Subsidence ◽  
Ground Subsidence ◽  
Additional Stress ◽  
Buried Pipeline ◽  
Buried Pipelines ◽  
Probability Integral Method ◽  
Coal Mining Subsidence

Buried pipelines influenced by coal mining subsidence will deform and generate additional stress during surface deformation. On the basis of the coordinating deformation relationship between buried pipeline and its surrounding soils, a stress analysis method of a buried pipeline induced by mining was proposed. The buried pipeline additional stresses were analyzed; meanwhile, a corresponding analysis process of the pipeline stresses was also presented during mining subsidence. Furthermore, based on the ground subsidence along the pipeline predicted in advance by the probability integral method, the additional stresses and Von Mises equivalent stresses and their distributions along the buried pipeline induced by the exploitation of a coal mining working face named 14101 were obtained. Meanwhile, a comparative analysis of additional stresses between simulation and analytical calculation was performed for the deep analysis and reliability of the results presented by the proposed methodology in this paper. The proposed method provides references for analysis of the additional stress and safety of buried pipelines under the influence of mining subsidence.

The Finite Element Analysis of South Cap Excavation of Left Branching of Ma on Shan Yangtze River Highway Bridge

2011 ◽  
Vol 255-260 ◽  
pp. 4207-4211
Author(s):  
Yue Zhang ◽  
Mi Zhou
Keyword(s):  
Yangtze River ◽  
Simulation Analysis ◽  
Soft Soil ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Highway Bridge ◽  
Foundation Pit ◽  
Element Analysis ◽  
Calculation Results ◽  
Stress And Deformation

South pile foundation of Ma On Shan Yangtze River Highway Bridge is big, deep, soft soil, groundwater rich. In order to guarantee the safeties of the foundation, its foundation pit supporting schemes are compared, selected and calculated, finally lock mouth steel pipe support is selected as the design and construction scheme. The three-dimensional simulation analysis of the scheme is calculated by using MIDAS software, simulated four construction condition is presented, and stress and deformation results of retaining structure on various operating conditions is obtained. The calculation results show that the palisade structure basic satisfies the requirements of caps excavation and caps concrete construction. The results of construction show that the construction method, model and parameters used in this paper are basic right, the reasonableness of Supporting is confirmed and for the similar large foundation pit construction provides useful reference.

Nonlinear Finite Element Analysis for Stress and Deformation of CFRD

2015 ◽  
Vol 744-746 ◽  
pp. 536-539
Author(s):  
Shu Yun Ding ◽  
Zhi Quan Huang ◽  
Shi Ming Yu
Keyword(s):  
Finite Element ◽  
Shear Failure ◽  
Material Model ◽  
Small Range ◽  
Element Analysis ◽  
Dam Foundation ◽  
Constitutive Material Model ◽  
Calculation Results ◽  
The Face ◽  
Stress And Deformation

Based on Duncan-Chang’s E-B constitutive material model, the finite element calculating model for a CFRD was established, and has obtained the stress-strain distribution and variety rule at the dam and the face slab in construction period and water store period. The calculation results show that: the stress-deformation behavior of the dam is normal, the deformation values within the acceptable range; the shear failure for the dam is almost impossible; stress concentration and tensile loading on small principal stress was exist on small range of the dam foundation covered by toe slab; the substantially change of water level has great effect on the deformation and camber of the face slabs; the faults structures in dam foundation only has affect the stress distribution of the foundation, but has weak impact of the stress and deformation of the dam body.

scholarly journals The Ground Settlement and the Existing Pipeline Response Induced by the Nonsynchronous Construction of a Twin-Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Shicheng Sun ◽  
Chuanxin Rong ◽  
Houliang Wang ◽  
Linzhao Cui ◽  
Xin Shi
Keyword(s):  
Three Dimensional ◽  
Ground Surface ◽  
Construction Process ◽  
Ground Settlement ◽  
Three Dimensional Model ◽  
Relative Stiffness ◽  
Twin Tunnel ◽  
Calculation Results ◽  
Negative Impacts ◽  
Final Settlement

Shielding tunnel construction always has negative impacts on the surrounding buildings. Because of repeated disturbances caused by the construction, more attention should be paid to the impacts of the nonsynchronous construction of a twin-tunnel. In this research, a three-dimensional model was established to simulate the construction process of a twin-tunnel in a section of the Hefei No. 4 metro line, and the calculation results were validated with the measured settlement data. Based on the model, the ground settlement and the existing pipeline responses were studied in detail. The results showed that, after the first tunnel (FT) construction, the settlement curves conformed to a Gaussian distribution. Additionally, after the second tunnel (ST) construction, the final settlement curves were no longer completely symmetrical. The influences of the twin-tunnel space and the pipeline-soil relative stiffness on the settlements were further studied. The results showed that the final settlement curves of the ground surface and the pipeline were mainly W-shaped, U-shaped, and V-shaped. As the twin-tunnel space increased and the pipeline-soil relative stiffness decreased, the settlement curve gradually changed from V-shaped to W-shaped. C was defined as the ratio of two maximum settlements in the W-shaped settlement curve. As the space increased, C started to decrease from 1 and then increased to 1.

Study on Deformation Mechanism of Tube Hydropiercing

2010 ◽  
Vol 97-101 ◽  
pp. 166-169 ◽  
Author(s):  
Qiang Wang ◽  
Na Teng ◽  
Dong Mei Cai ◽  
Shi Hong Zhang
Keyword(s):  
Numerical Simulation ◽  
Deformation Mechanism ◽  
3D Fem ◽  
Plastic Bending ◽  
Inner Pressure ◽  
Calculation Results ◽  
Punching Process ◽  
Stress And Deformation ◽  
Tubular Component

The numerical simulation of tube hydropiercing process on a typical tubular component was conducted by employing the FEM code MARC in order to investigate the deformation mechanism of tube hydropiercing. The 3D FEM models have been established in both inward and outward punching operations. Based on the calculation results of the distributions and their changes of stress and deformation, a plastic bending deformation zone in the vicinity of the hole’s edge has been discovered, which differs greatly from that in the conventional sheet metal punching process. Influence of inner pressure on the quality of hydropierced hole was also investigated.

Stress and Deformation Analysis of Concrete Face Rockfill Dam Based on ABAQUS

2014 ◽  
Vol 998-999 ◽  
pp. 538-544
Author(s):  
Chun Hui Fang ◽  
Xue Wang
Keyword(s):  
Material Model ◽  
Secondary Development ◽  
Deformation Analysis ◽  
Analysis Method ◽  
Rockfill Dam ◽  
Calculation Results ◽  
Practical Engineering ◽  
Stress And Deformation ◽  
Concrete Face ◽  
Concrete Face Rockfill Dam

A new analysis method of stress and deformation of concrete face rockfill dam is established based on ABAQUS. This new approach includes secondary development of Duncan E-B material model and secondary development of Goodman frictional model of contact between concrete face and cushion. Meanwhile, contact characteristics is considered among concrete face and between concrete face and plinth. According to dam prototype observation, the analytic results are in good agreement with calculation results from the practical engineering, which indicates that the analysis method can be used widely.

Failure Analysis of 12 Inch Pipeline Riser

2014 ◽  
Author(s):  
Frank Gareau ◽  
Alex Tatarov
Keyword(s):  
Internal Surface ◽  
Fracture Initiation ◽  
Slag Inclusion ◽  
Ground Movement ◽  
Simultaneous Action ◽  
Additional Stress ◽  
Contributing Factors ◽  
Element Analysis ◽  
Material Fracture ◽  
Corrosion Pits

A rupture and an explosion occurred on a 12.75 inch OD high pressure gas pipeline after 40 years in service. The force of the explosion broke the riser off and sent two large pieces of the riser flying into the surrounding forest. The failure occurred as a result of the simultaneous action of several contributing factors: • The weld had a non-specified profile (a step) and contained a large slag inclusion at the location of fracture initiation. • Corrosion pits were growing from the internal surface close to the weld root. • Dewpoint corrosion took place on the internal surface of the riser close to massive flanges. • The dehydrator at the compressor station was not removing the target amount of moisture. • Low temperatures contributed to the failure by decreasing material fracture toughness. • Ground movement could have created additional stress required for the failure to occur. Several of the above listed factors (pitting corrosion, ground movement, malfunctioning of the dehydrator) developed with time, which explains the delayed mode of failure. The conclusions were supported by Finite Element Analysis and Fracture Mechanics calculations.

Effect of Geometry of Grooves on Connection Strength of Hydraulically Expanded Tube-to-Tubesheet Joints

2005 ◽  
Vol 127 (4) ◽  
pp. 430-435 ◽  
Author(s):  
H. F. Wang ◽  
Z. F. Sang
Keyword(s):  
Groove Depth ◽  
Geometrical Factor ◽  
Geometrical Parameters ◽  
Connection Strength ◽  
Design And Manufacturing ◽  
Average Residual ◽  
Calculation Results ◽  
Stress And Deformation ◽  
Axisymmetrical Model ◽  
Residual Stress And Deformation

The object of this paper is to investigate the effect of the geometry of circumferential grooves on the connection strength of hydraulically expanded tube-to-tubesheet joints of heat exchangers. Seven-tube models with different groove widths, depths, spacings, and locations were fabricated under the same expansion pressure by commercial hydraulic expanders. Then the corresponding pullout forces were gained by experimental means. In addition, the process of hydraulic expansion of tube-to-tubesheet joints was simulated using the nonlinear finite element method based on a two-dimensional (2D) axisymmetrical model. The residual stress and deformation of joints were determined, and the effect of geometrical parameters of the grooves on the connection strength of joints was studied in terms of the average residual contact pressure of the joints. The experimental and calculation results indicate that the most important geometrical factor for determining the connection strength is the groove width. Groove depth, spacing, and location have a secondary effect. Optimum geometrical sizes of grooves are proposed based on maximum axial strength. These can provide a reference for the revision of design and manufacturing codes.

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