Nonlinear analysis of footings on granular bed–stone column improved soft soil

2011 ◽  
Vol 6 (3) ◽  
pp. 185-194 ◽  
Author(s):  
Priti Maheshwari ◽  
Shubha Khatri
Keyword(s):  
Nonlinear Analysis ◽  
Soft Soil ◽  
Stone Column ◽  
Granular Bed

Improvement of Soft Soil by Stone Column Treated with Bentonite

2020 ◽  
Vol 857 ◽  
pp. 283-291
Author(s):  
Safa Hussain Abid Awn ◽  
Jasim M. Abbas
Keyword(s):  
Clayey Soil ◽  
Slenderness Ratio ◽  
Soft Soil ◽  
Field Tests ◽  
Stone Column ◽  
Laboratory Model ◽  
Mix Proportion ◽  
Effective Depth ◽  
Concrete Footing ◽  
The Ideal

Soft clayey soils cover wide Iraqi areas specially the regions close to rivers and the southern part of this country Heavy weight structures like: highways, dams, multiple story buildings are suffering unacceptable settlement, when constructing on soft soils. The high contamination of water in such soils decrease the effective stress and reduce bearing capacity. The need was appeared to improve such problematic soil by the use of new technique of stone column treated with different percentages of natural bentonite by a series of field tests using full scale concrete footing constructed on soft soil in addition to a laboratory model to investigate settlement with time at constant stress. The soil that used in this study is natural clayey soil, brought from a location south of Diyala governorate, from a farm area. The study includes also: The effect of stone column diameter treated with bentonite on the behavior of footing constructing on soft clayey soil, The effect of stone column length on the behavior of footing on such soils. Results of field and laboratory model tests reviled that the treated model by stone column mixed with 40% bentonite is the ideal one, which reduces the settlement by 55%. In other hand problems of uneven settlements appear when using 60% bentonite as a mix proportion. The Ideal slenderness ratio (Ds/Ls<25%). The effective depth of stone column treated with bentonite is (1/3H).

scholarly journals Stability analysis of roadway embankments supported by stone columns with the presence of water table under short-term and long-term conditions

2018 ◽  
Vol 162 ◽  
pp. 01013 ◽  
Author(s):  
Shaymaa Tareq Kadhim ◽  
Ziad Bashar Fouad
Keyword(s):  
Water Table ◽  
Factor Of Safety ◽  
Soft Soil ◽  
Stone Columns ◽  
Stone Column ◽  
Stability Factor ◽  
Short Term ◽  
Long Term Conditions ◽  
The Stability

Use of stone column technique to improve soft foundation soils under roadway embankments has proven to increase the bearing capacity and reduce the potential settlement. The potential contribution of stone columns to the stability of roadway embankments against general (i.e. deep-seated) failure needs to be thoroughly investigated. Therefore, a two-dimensional finite difference model implemented by FLAC/SLOPE 7.0 software, was employed in this study to assess the stability of a roadway embankment fill built on a soft soil deposit improved by stone column technique. The stability factor of safety was obtained numerically under both short-term and long-term conditions with the presence of water table. Two methods were adopted to convert the three-dimensional model into plane strain condition: column wall and equivalent improved ground methods. The effect of various parameters was studied to evaluate their influence on the factor of safety against embankment instability. For instance, the column diameter, columns’ spacing, soft soil properties for short-term and long-term conditions, and the height and friction angle of the embankment fill. The results of this study are developed in several design charts.

Estimating long-term settlement of floating stone column groups

2014 ◽  
Vol 51 (7) ◽  
pp. 770-781 ◽  
Author(s):  
J.T. Shahu ◽  
Y.R. Reddy
Keyword(s):  
Finite Element ◽  
Soft Soil ◽  
Group Behavior ◽  
Stone Column ◽  
Finite Element Analyses ◽  
Modified Cam Clay ◽  
Single Column ◽  
Foundation Parameters ◽  
Column Group

Design charts for estimating long-term drained settlement of floating stone column group foundations are presented based on three-dimensional, elastoplastic, finite element analyses. In the analyses, the soft soil behavior is represented by the modified Cam-clay model while the stone column and mat are represented by the Mohr–Coulomb model. The finite element predictions are calibrated against model test results. A detailed parametric study of prototype stone column group foundations of various configurations is carried out to evaluate the relative importance of various foundation parameters on the group response. Next, finite element analyses of corresponding unit cells and single columns are performed. Reasonable correlations of load responses are found between single column and group behavior. Group and single column responses are then used to investigate Sg/S1 relationship with different foundation parameters, where Sg and S1 represent the settlement of the group and single column, respectively.

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