Influence of exsolved gases on slope performance at the Sarnia approach cut to the St. Clair Tunnel

2010 ◽  
Vol 47 (9) ◽  
pp. 971-984 ◽  
Author(s):  
J. Paul Dittrich ◽  
R. Kerry Rowe ◽  
Dennis E. Becker ◽  
K. Y. Lo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Effective Stress ◽  
New Work ◽  
Element Analysis ◽  
Natural Gases ◽  
Fine Grained ◽  
Consolidation Theory ◽  
Naturally Occurring ◽  
South Slope

In 1993, over 100 years after the completion of the original St. Clair Tunnel and its approach cuts, work commenced on the new St. Clair Tunnel. The new tunnel used the existing approaches, but required additional excavation to widen and deepen the original cuts. In Sarnia, the new work initiated unusual deep-seated deformations on the south slope of the approach. Effective stress finite element analysis (FEA), using an elliptical cap soil model coupled with Biot consolidation theory, was used to model the 1993 construction, but initial predictions were unable to capture the trend of deformations noted in the field. Naturally occurring gases are frequently encountered near the base of the overburden in the Sarnia area and this phenomenon was observed during drilling investigations in the Sarnia approach cut. Including the effects of the presence of exsolved natural gases in fine-grained soils subjected to unloading in the FEA results in substantially better predictions in the trend of deformations on the slopes of the approach cut.

STUDY OF HOLLOW STEMMED HIP BONE FORMING

2017 ◽  
Vol 41 (4) ◽  
pp. 531-542 ◽  
Author(s):  
Dyi-Cheng Chen ◽  
Jheng-Guang Lin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Titanium Alloys ◽  
Effective Stress ◽  
Experimental Results ◽  
Analysis Software ◽  
Element Analysis ◽  
3D Finite Element ◽  
Friction Factors ◽  
Punch Load

This study investigated hollow stemmed hip forging for enhancing the biocompatibility of Ti-6AL-4V titanium alloys. Instead of using the expensive titanium billet, this study applied DEFORMTM 3D finite element analysis software to simulate and analyze stem forming with respect to different die temperatures, friction factors, punch types, forging velocities, and billet temperatures. On the basis of its shape, a punch can be classified as flat head, ladder shaped, spherical, and conical. These differences affect the effective stress and punch load after stem formation. The experiment parameters were determined using the Taguchi L16 (45) orthogonal table. Both the simulated and experimental results indicated that the error for the size of the bone stem was less than 2%.

Study of Non-Monotonity of Forming Processes Using Finite Element Analysis

2010 ◽  
Vol 659 ◽  
pp. 373-378 ◽  
Author(s):  
Kristóf Bobor ◽  
György Krállics
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
Finite Element ◽  
Velocity Field ◽  
Severe Plastic Deformation ◽  
Mechanical Analysis ◽  
Asymmetric Rolling ◽  
Lagrange Method ◽  
Element Analysis ◽  
Fine Grained

The method of severe plastic deformation is often used to produce bulk ultra-fine grained materials. Numerous methods exist, which are able to produce ultra fine grained materials. Investigated the mechanical schema of these procedures, we searched for such attributes, which characterize the mentioned techniques. By our previous researches can be established, that for these techniques shear deformation as well as the so-called non-monotonic deformation are characteristic. In this paper a degree of non-monotonity is presented, which is an appropriate measure to characterize the forming processes. Besides this the combined Euler – Lagrange method is showed, which is appropriate to obtain a continuous velocity field from finite element analysis. Eventually the mechanical analysis of the extrusion, conventional and asymmetric rolling is showed with respect to the non-monotonity.

Effective-stress finite element analysis of spudcan penetration with lattice leg in clay

2013 ◽  
Author(s):  
Yu Ping Li ◽  
Fook Hou Lee ◽  
Jiang Tao Yi ◽  
Xi Ying Zhang ◽  
Siang Huat Goh
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Effective Stress ◽  
Element Analysis

Effective-Stress Finite Element Analysis of Spudcan Penetration

2012 ◽  
Author(s):  
Jiang Tao Yi ◽  
Fook Hou Lee ◽  
Siang Huat Goh ◽  
Yu Ping Li ◽  
Xi Ying Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Analysis ◽  
Pore Pressure ◽  
Effective Stress ◽  
Excess Pore Pressure ◽  
Element Analysis ◽  
Pore Pressures ◽  
Excess Pore Pressures ◽  
Excess Pore

The numerical modeling of spudcan penetration involves technical challenges posed by large soil deformation coupled with significant material non-linearity. The Lagrangian approach commonly used for solid stress analysis often does not work well with large deformations, resulting in premature termination of the analysis. Recently, the Arbitrary Langrangian Eulerian (ALE) and the Eulerian methods have been used in spudcan analysis to overcome problems caused by the soil flow and large deformation. However, most of the reported studies are based on total stress analysis and therefore shed no light on the excess pore pressures generated during spudcan installation. As a result, much remains unknown about the long-term behaviour of spudcans in the ground, which is affected by the dissipation of excess pore pressures. This paper reports an effective-stress finite element analysis of spudcan installation in an over-consolidated (OC) soft clay. The Eulerian analysis was conducted using ABAQUS/ Explicit, with the effective stress constitutive models coded via the material subroutine VUMAT. The results demonstrated the feasibility of conducting effective-stress finite element analysis for undrained spudcan penetration in OC clays. The paper discusses the flow mechanism, stable cavity depths and bearing capacity factors when spudcan installation occurs in various OC soils. It was found that the pore pressure build-up concentrates in a bulb-shaped zone surrounding the spudcan. The size of the pore pressure bulb increases with increasing penetration. The maximum excess pore pressure, which is generated near the spudcan tip, is predominantly controlled by the undrained shear strength at the tip level.

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