ESTIMATING THE COEFFICIENT OF SUBGRADE REACTION FOR PLANE STRAIN CONDITIONS
This paper reviews the limitations of various simple and complex methods available for estimating the coefficient of subgrade reaction k, and proposes a new method developed using results from plane strain finite element analyses of a loaded beam or slab resting on the surface of a homogeneous elastic soil layer. Because the derivation is based on the assumption of plane strain conditions, the method is particularly applicable to the design of cut-and-cover tunnel slabs or other similar structures. The proposed method, denoted as the modified beam on elastic foundation (MBEF) method, differs from standard procedures in that the derived value of k varies with position under the structural slab. The variables which affect the value of k include the soil modulus and Poisson's ratio, the beam stiffness, the thickness of the soil layer relative to the slab or beam dimension and the type of loading conditions. All of these variables are considered and factored into a set of design charts and tables so that the method of estimating k can easily be used with standard structural frame analysis programs. The proposed MBEF method is particularly accurate when compared to finite element solutions for relatively rigid slabs. For slabs which are relatively flexible, the calculated maximum moments in the slab are less accurate, but tend to be conservative, with some exceptions as described in the paper. (A)
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Corporate Authors:
Thomas Telford Limited
London, United Kingdom -
Authors:
- Liao, SSC
- Conference:
- Publication Date: 1995-7
Language
- English
Media Info
- Features: References;
- Pagination: p. 166-81
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Serial:
- Volume: 113
- Issue Number: 3
Subject/Index Terms
- TRT Terms: Coefficient of subgrade reaction; Finite element method; Foundations; Loads; Soil mechanics
- ITRD Terms: 5787: Coefficient of subgrade reaction; 6490: Finite element method; 3377: Foundation; 5567: Load; 5755: Soil mechanics
- Subject Areas: Geotechnology;
Filing Info
- Accession Number: 00719954
- Record Type: Publication
- Source Agency: Transport Research Laboratory
- Files: ITRD
- Created Date: Apr 26 1996 12:00AM