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Numerical Analysis of Embankment Stability over Deep Mixed Foundations
When embankments are constructed over soft foundations, stability often becomes one of the controlling factors in design. Deep mixing methods have been commonly used as an alternative to improve soft soil to enhance the stability. Bishop's modified method is a commonly adopted approach for analyzing slope stability including embankments over deep mixed (DM) foundations. Bishop's modified method assumed failure along a circular slip surface and the soils along this slip surface provide shear resistance. However, experimental and numerical studies have showed that deep mixed columns under a combination of vertical and horizontal forces could fail due to shearing or bending. The bending failure cannot be analyzed by Bishop's method. A finite difference method was used in this study to evaluate the factors influencing the stability of embankments over deep mixed foundations, which include strength, spacing, and size of DM columns, undrained shear strength and thickness of soft soil, quality and height of embankment fill, and traffic loading. Mohr-Coulomb failure criterion was used for embankment fill, foundation soil, and deep mixed columns. In addition, the tensile strength of deep mixed columns was assumed to be 10% of their undrained shear strength. A row of deep mixed columns was modeled as a wall in 2-D for simplicity of analysis. Deep mixed columns were embedded into a firm soil to create a possibility of bending failure. The numerical analysis indicated that the factors of safety of the embankments over DM foundations depend on these influence factors and the failure mode changes from deep-seated failure to slope failure within the embankment fill.
Numerical Analysis of Embankment Stability over Deep Mixed Foundations
When embankments are constructed over soft foundations, stability often becomes one of the controlling factors in design. Deep mixing methods have been commonly used as an alternative to improve soft soil to enhance the stability. Bishop's modified method is a commonly adopted approach for analyzing slope stability including embankments over deep mixed (DM) foundations. Bishop's modified method assumed failure along a circular slip surface and the soils along this slip surface provide shear resistance. However, experimental and numerical studies have showed that deep mixed columns under a combination of vertical and horizontal forces could fail due to shearing or bending. The bending failure cannot be analyzed by Bishop's method. A finite difference method was used in this study to evaluate the factors influencing the stability of embankments over deep mixed foundations, which include strength, spacing, and size of DM columns, undrained shear strength and thickness of soft soil, quality and height of embankment fill, and traffic loading. Mohr-Coulomb failure criterion was used for embankment fill, foundation soil, and deep mixed columns. In addition, the tensile strength of deep mixed columns was assumed to be 10% of their undrained shear strength. A row of deep mixed columns was modeled as a wall in 2-D for simplicity of analysis. Deep mixed columns were embedded into a firm soil to create a possibility of bending failure. The numerical analysis indicated that the factors of safety of the embankments over DM foundations depend on these influence factors and the failure mode changes from deep-seated failure to slope failure within the embankment fill.
Numerical Analysis of Embankment Stability over Deep Mixed Foundations
Han, Jie (author) / Sheth, Abhijit R. (author) / Porbaha, Ali (author) / Shen, Shui-Long (author)
GeoTrans 2004 ; 2004 ; Los Angeles, California, United States
2004-07-21
Conference paper
Electronic Resource
English
Numerical Analysis of Embankment Stability over Deep Mixed Foundations
| British Library Conference Proceedings | 2004
Stability of Embankment Foundations
| ASCE | 2021