scholarly journals Effect of Tunnel Progress on the Settlement of Existing Piled Foundation

2019 ◽  
Vol 41 (2) ◽  
pp. 102-113 ◽  
Author(s):  
Raid Ramzi Al-Omari ◽  
Madhat Shakir Al-Soud ◽  
Osamah Ibrahim Al-Zuhairi
Keyword(s):  
Ground Deformation ◽  
Three Dimensional ◽  
Ground Surface ◽  
Tunnel Boring Machine ◽  
Longitudinal Direction ◽  
Tunnel Lining ◽  
Elastic Model ◽  
Element Analysis ◽  
Tunnel Boring ◽  
Three Dimensional Finite Element

AbstractTunnel construction below or adjacent to piles will affect the performance and eventually the stability of piles due to ground deformation resulting in the movement of piles and changes in the axial force distribution along the piles. A three dimensional finite element analysis using PLAXIS 3D (2013) was performed to study the behaviour of a single pile and 3 x 3 piles group during the advancement of shield tunnelling in ground. The 10-node tetrahedral elements were used to model both the soil and the tunnel lining. The Hardening Soil (HS) model was used to simulate the soil structure interaction at the tunnel-soil interface. An isotropic elastic model was used for the pile, piles cap, tunnel lining and tunnel boring machine shield (TBM). Several parametric studies were attempted including the longitudinal, lateral, and vertical tunnel location relative to pile embedded in different types of soil (clay or sand). The results showed that the pile head settlement increases during the tunnelling advancement in larger values than that for ground surface settlement. A zone of influence was determined in the range of twice the tunnel diameter in the longitudinal direction (forward and backward of the pile), and transverse direction (left and right of the tunnel centreline). If the tunnel boring is kept off this zone then there is no fear of pile collapse.

scholarly journals 3D MODELLING OF TUNNEL EXCAVATION USING PRESSURIZED TUNNEL BORING MACHINE IN OVERCONSOLIDATED SOILS

2013 ◽  
Vol 35 (2) ◽  
pp. 3-17 ◽  
Author(s):  
Rafik Demagh ◽  
Fabrice Emeriault
Keyword(s):  
Numerical Simulation ◽  
Urban Areas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Tunnel Boring Machine ◽  
Confining Pressure ◽  
Soil Mass ◽  
Shield Tunnel ◽  
Tunnel Boring ◽  
Boring Machines

Abstract The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

An interpretation of ground movements recorded during construction of the Donkin-Morien tunnel

1991 ◽  
Vol 28 (2) ◽  
pp. 239-254 ◽  
Author(s):  
F. Pelli ◽  
P. K. Kaiser ◽  
N. R. Morgenstern
Keyword(s):  
Three Dimensional ◽  
Back Analysis ◽  
Tunnel Boring Machine ◽  
Laboratory Measurements ◽  
Tunnel Face ◽  
Tunnel Boring ◽  
Deformation Properties ◽  
Dimensional Finite Element ◽  
Strength And Deformation ◽  
Three Dimensional Finite Element

A tunnel excavated by a tunnel boring machine was monitored extensively by means of extensometers installed near the tunnel face. Consequently, the three-dimensional state existing at the time of installation must be considered for the interpretation of the monitoring data. Results from three-dimensional finite element simulations are used to back-calculate rock mass strength and deformation properties. The purpose of this study was to establish and test various approaches of back-analysis. Results are compared with field and laboratory measurements. On the basis of these analyses, the paper provides guidance on how field data can be used for back-analysis purposes even when the ground behaves in a nonelastic manner. Key words: tunnelling, monitoring, tunnel boring, back-analysis, nonlinearity.

Three-dimensional deformation behavior of the Taipei National Enterprise Center (TNEC) excavation case history

2000 ◽  
Vol 37 (2) ◽  
pp. 438-448 ◽  
Author(s):  
Chang-Yu Ou ◽  
Bor-Yuan Shiau ◽  
I-Wen Wang
Keyword(s):  
Finite Element ◽  
Plane Strain ◽  
Case History ◽  
Three Dimensional ◽  
Ground Surface ◽  
Element Analysis ◽  
Case Record ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
National Enterprise

The Taipei National Enterprise Center (TNEC) excavation project was constructed using the top-down construction method, in which a diaphragm wall was supported by the concrete floor slab. Previous studies have reported the deformation and stress-strain behaviors along the main observation section, which was considered to be in the plane strain condition. This paper examines the three-dimensional movements of the soil and wall through field observations and finite element analyses. The results indicate that the soil outside the excavation zone tends to move toward the excavation center. Such a tendency increases with excavation depth. The soil settlement near the corner of the excavation is less than that near the center due to the corner effect. The empirical equation proposed by Clough and O'Rourke for estimating the ground settlement appears to be adequate for plane strain sections and other non-plane strain sections. Numerical studies indicate that the wall deformation and ground surface settlement can be reasonably predicted using three-dimensional finite element analysis. Parametric studies revealed that for this case record zoned excavation commencing near the final stage of excavation has very little effect on excavation behavior.Key words: TNEC case history, deep excavation, deformation, three-dimensional finite element method.

A Three-Dimensional Finite Element Analysis of Unburied Flexible Flowline: A Case Study

2002 ◽  
Author(s):  
Wenchao Zhang ◽  
Justin Tuohy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Longitudinal Direction ◽  
Flexible Pipe ◽  
Element Analysis ◽  
Upheaval Buckling ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Pipelines in the service of conveying hot fluid will tend to expand due to pressure and differential temperature. However, since the flowline is generally fixed at the end terminations to rigid structures or equipment, such an expansion will be restricted in longitudinal direction. This is particularly the case for the section remote from the pipe ends, and results in an axial compression in the pipe section. In many cases, a subsea flowline has to be trenched or buried for the purposes of protection and thermal insulation. Consequently, the lateral movement of a flexible flowline is greatly limited, and an upward displacement is encouraged that may become excessive. Eventually, the flowline may lift out of the trench when the uplift resistance provided by the backfill cover and self-weight of the flowline is gradually overcome by the strain energy built up in the flowline. For flexible pipe, it is this excessive upward deformation being termed as the Upheaval Buckling, which can be prevented by employing adequate downward restraint, such as sand bag/rock dump or by designing a subsea pipe route to overcome this phenomenon. In this paper a case study of the full three-dimensional finite element analysis of a trenched but unburied 6.0-inch production flowline is presented following a description of Wellstream Finite Element Method (FEM) based methodology for Upheaval Buckling analysis of flexible pipes. The effect Bending Stiffness Hysteresis and Upheaval Creep–unique to flexible pipe characteristics, is considered in addition to the general loads such as the flowline self-weight and backfill, pretension, pressure, temperature distribution and prescribed forces (either concentrated or distributed) and displacements. The effects of environmental loads, such as the action of currents that would result in scouring off the backfill, can also be addressed. The finite element analysis program package ANSYS was chosen for this case study due to its special feature of ANSYS Parametric Design Language (APDL) and contact/target elements; and the general three-dimensional shell and solid elements were used to represent the flexible pipe and trench soil respectively.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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