Analysis Using the Soft Soil Model
The analysis employs the modified compression index λ and is based on the Soft soil elastic-plastic model developed in the University of Cambridge. The soil deformation assumes the volumetric strain to be linearly dependent on the change of effective mean stress ε plotted in the natural logarithmic scale. The settlement of the ith layer is then provided by:
where: | σor,i | - | vertical component of geostatic stress in the middle of ith layer |
σz,i | - | vertical component of incremental stress (e.g. stress due to structure surcharge) inducing layer compression | |
hi | - | thickness of the ith layer | |
λ | - | modified compression index in the ith layer |
The analysis requires inputting the modified compression index λ usually obtained from triaxial laboratory measurements.
If the modified compression index λ is not known, it is possible to specify the compression index CC together with an average value of the void ratio e (if you do not know it, it is sufficient to provide the initial void ratio eo) and the program then performs an approximate computation of the modified compression index λ using the available information.
Literature:
Burland J.B. The yielding and dilatation of clay (correspondence), Géotechnique, 15 (2),1965, str. 211-214.