Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

A typical top-down deep excavation project in Shanghai was carefully monitored during the construction process. This case history was back-analysed with a complex 3D FEM numerical model in ABAQUS to investigate the influence of different modelling procedures. The model considered the detailed construction procedures and structural information. The calculations included the small-strain stiffness of the soil and thermal shrinkage of the concrete beams and slabs. The small-strain stiffness is modelled with a multi-surface soil model developed at Oxford which has been implemented into ABAQUS. The diaphragm wall was modelled as an anisotropic linear elastic material to represent the effect of the joints in the wall. The beam and slabs were modelled as a linear elastic material and including the shrinkage of concrete. The numerical results captured the main excavation behavior and agreed well with the field measurements. Two sets of calculations were conducted to investigate the influence of soil models and thermal shrinkage on the computed excavation behavior. The results showed that small-strain soil stiffness is crucial to capture the excavation behavior and the thermal shrinkage of concrete should not be neglected in deep excavation problem.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

3D FEM Modelling of a Deep Excavation Case Considering Small-Strain Stiffness of Soil and Thermal Shrinkage of Concrete

Chicago, Illinois

A typical top-down deep excavation project in Shanghai was carefully monitored during the construction process. This case history was back-analysed with a complex 3D FEM numerical model in ABAQUS to investigate the influence of different modelling procedures. The model considered the detailed construction procedures and structural information. The calculations included the small-strain stiffness of the soil and thermal shrinkage of the concrete beams and slabs. The small-strain stiffness is modelled with a multi-surface soil model developed at Oxford which has been implemented into ABAQUS. The diaphragm wall was modelled as an anisotropic linear elastic material to represent the effect of the joints in the wall. The beam and slabs were modelled as a linear elastic material and including the shrinkage of concrete. The numerical results captured the main excavation behavior and agreed well with the field measurements. Two sets of calculations were conducted to investigate the influence of soil models and thermal shrinkage on the computed excavation behavior. The results showed that small-strain soil stiffness is crucial to capture the excavation behavior and the thermal shrinkage of concrete should not be neglected in deep excavation problem.