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Finita elementanalys av en kajspont

Akbar, Sinan LU (2011) In TVGT-5000 VGTM01 20102
Geotechnical Engineering
Abstract
The master’s dissertation deals with finite element analysis of a quay sheet pile. The main aims are to calculate the deformation and section forces for the sheet pile at different construction stages, get the most realistic soil parameters for the stabilized clay soil and to find out the minimum possible steel section for the sheet pile wall.

The sheet pile is built in order to expand the existing harbour in Gävle city. The space between the newly built sheet pile and the existing harbour is filled with clay soil which is excavated from seabed and is treated with binder (cementing material).

The construction process of the sheet pile consists of four construction stages, the first stage represents a case where the sheet pile is... (More)
The master’s dissertation deals with finite element analysis of a quay sheet pile. The main aims are to calculate the deformation and section forces for the sheet pile at different construction stages, get the most realistic soil parameters for the stabilized clay soil and to find out the minimum possible steel section for the sheet pile wall.

The sheet pile is built in order to expand the existing harbour in Gävle city. The space between the newly built sheet pile and the existing harbour is filled with clay soil which is excavated from seabed and is treated with binder (cementing material).

The construction process of the sheet pile consists of four construction stages, the first stage represents a case where the sheet pile is driven into a rock filling and the water level is different on both sides of the sheet pile, the second stage represents another case where the land side of the sheet pile is filled with the treated clay soil, the third stage represents a case where a layer of crushed stone is distributed over the treated clay soil in order to improve its shear strength and the fourth stage represents a case where the height of the crushed stone layer is increased to 2,3 m and the sheet pile is pushed back by using a pre-stressed anchor.

A geometric model which includes all construction stages is created in the FE-software PLAXIS 2D. The model is created as a two dimensional model and plane strain is assumed. Soil parameters for all the soil layers in the model are based on experience, the material parameters for the sheet pile and the anchor are provided by the producer. Mohr-Coulomb
MC model is used for all the soil layers and the linear elasticity model is used for the sheet pile and the anchor.

The result of FE-analysis shows that the maximum horizontal displacement for the sheet pile in x-direction, maximum shear force and maximum moment in the sheet pile for the first construction stage are -567 mm, -345,8 kN/m and 1048 kNm/m, for the second stage are 292,2 mm, 191,2 kN/m and -559,5 kNm/m, for the third stage are 328,2 mm, 204,5 kN/m and -595,5 kNm/m and the result for the fourth stage are 403,8 mm, 108,6 kN/m and 225,7 kNm/m.

Results from an analysis based on hand calculation expressions gives bigger displacement, shear force and moment than the results from FE-analysis.

A sensibility analysis is performed by FEM in order to find which parameter for the soil layers has the major influence on the sheet pile displacement. The analysis shows that the undrained shear strength, unit weight of the treated clay soil and the friction angle of the crushed stone has maximum influence on the sheet pile displacement.

An iterative analysis is performed by FEM based on the geometric model in the second and third construction stages in order to obtain the most probable parameters for the treated clay soil in these stages. Attention is mainly directed to the undrained shear strength of treated clay because its unit weight and elasticity module are assumed to be given.

Assessment of the resulting sheet pile displacement from several FE-analyses for the second and third construction stages with different values for the undrained shear strength of the treated clay soil and comparison with the measured displacement shows that the most probable value of the undrained shear strength of the treated clay soil in the second construction stage is 1,5 kPa+1 kPa/m and in the third stage is 19 kPa+1 kPa/m.

Two FE-analyses are performed with two different steel cross sections (AZ 37-700 and AZ 39-700) for the sheet pile and based on the resulting soil parameters for the treated clay soil in the second construction stage. Comparison of the resulting sheet pile displacement from both of the analyses shows that the difference in displacement is negligible. Similarly, two FEanalyses are performed with the same two different steel cross sections and based on the resulting soil parameters for the treated clay soil in the third construction stage and once again the analysis results show that the differences in the sheet pile displacement between the two calculations is negligible. (Less)
Please use this url to cite or link to this publication:
author
Akbar, Sinan LU
supervisor
organization
course
VGTM01 20102
year
type
H3 - Professional qualifications (4 Years - )
subject
publication/series
TVGT-5000
report number
TVGT-5045
ISSN
0281-6679
language
Swedish
id
3163949
alternative location
http://www.byggvetenskaper.lth.se/geoteknik/english/publications/masters_dissertations/
date added to LUP
2012-11-12 10:18:11
date last changed
2015-03-24 15:46:47
@misc{3163949,
  abstract     = {The master’s dissertation deals with finite element analysis of a quay sheet pile. The main aims are to calculate the deformation and section forces for the sheet pile at different construction stages, get the most realistic soil parameters for the stabilized clay soil and to find out the minimum possible steel section for the sheet pile wall.

The sheet pile is built in order to expand the existing harbour in Gävle city. The space between the newly built sheet pile and the existing harbour is filled with clay soil which is excavated from seabed and is treated with binder (cementing material).

The construction process of the sheet pile consists of four construction stages, the first stage represents a case where the sheet pile is driven into a rock filling and the water level is different on both sides of the sheet pile, the second stage represents another case where the land side of the sheet pile is filled with the treated clay soil, the third stage represents a case where a layer of crushed stone is distributed over the treated clay soil in order to improve its shear strength and the fourth stage represents a case where the height of the crushed stone layer is increased to 2,3 m and the sheet pile is pushed back by using a pre-stressed anchor.

A geometric model which includes all construction stages is created in the FE-software PLAXIS 2D. The model is created as a two dimensional model and plane strain is assumed. Soil parameters for all the soil layers in the model are based on experience, the material parameters for the sheet pile and the anchor are provided by the producer. Mohr-Coulomb
MC model is used for all the soil layers and the linear elasticity model is used for the sheet pile and the anchor.

The result of FE-analysis shows that the maximum horizontal displacement for the sheet pile in x-direction, maximum shear force and maximum moment in the sheet pile for the first construction stage are -567 mm, -345,8 kN/m and 1048 kNm/m, for the second stage are 292,2 mm, 191,2 kN/m and -559,5 kNm/m, for the third stage are 328,2 mm, 204,5 kN/m and -595,5 kNm/m and the result for the fourth stage are 403,8 mm, 108,6 kN/m and 225,7 kNm/m.

Results from an analysis based on hand calculation expressions gives bigger displacement, shear force and moment than the results from FE-analysis.

A sensibility analysis is performed by FEM in order to find which parameter for the soil layers has the major influence on the sheet pile displacement. The analysis shows that the undrained shear strength, unit weight of the treated clay soil and the friction angle of the crushed stone has maximum influence on the sheet pile displacement.

An iterative analysis is performed by FEM based on the geometric model in the second and third construction stages in order to obtain the most probable parameters for the treated clay soil in these stages. Attention is mainly directed to the undrained shear strength of treated clay because its unit weight and elasticity module are assumed to be given.

Assessment of the resulting sheet pile displacement from several FE-analyses for the second and third construction stages with different values for the undrained shear strength of the treated clay soil and comparison with the measured displacement shows that the most probable value of the undrained shear strength of the treated clay soil in the second construction stage is 1,5 kPa+1 kPa/m and in the third stage is 19 kPa+1 kPa/m.

Two FE-analyses are performed with two different steel cross sections (AZ 37-700 and AZ 39-700) for the sheet pile and based on the resulting soil parameters for the treated clay soil in the second construction stage. Comparison of the resulting sheet pile displacement from both of the analyses shows that the difference in displacement is negligible. Similarly, two FEanalyses are performed with the same two different steel cross sections and based on the resulting soil parameters for the treated clay soil in the third construction stage and once again the analysis results show that the differences in the sheet pile displacement between the two calculations is negligible.},
  author       = {Akbar, Sinan},
  issn         = {0281-6679},
  language     = {swe},
  note         = {Student Paper},
  series       = {TVGT-5000},
  title        = {Finita elementanalys av en kajspont},
  year         = {2011},
}