Modeling and Numerical Analysis of Expansive Soil in Stress Path Tests

2010 ◽  
Author(s):  
Syed Abdul Mofiz ◽  
Mohammad Nurul Islam
Keyword(s):  
Numerical Analysis ◽  
Expansive Soil ◽  
Stress Path

A Numerical Method of the Flexible Pavement Supported by SSC on Expansive Soil

2016 ◽  
Vol 845 ◽  
pp. 62-69 ◽  
Author(s):  
Agus Setyo Muntohar
Keyword(s):  
Finite Element Method ◽  
Numerical Analysis ◽  
Large Scale ◽  
Expansive Soil ◽  
Material Model ◽  
Soil Improvement ◽  
Flexible Pavement ◽  
Control Model ◽  
Differential Settlement ◽  
Vehicle Loading

Many road and highway have been constructed over the expansive soil in Java island without proper soil improvement for the subgrade. The behavior of the column on the expansive soil needs for study numerically and large scale. In this study, a numerical analysis is performed to study the effect of swelling on the deformation of the soil stabilized column supported flexible pavement. The main focus of the research is to obtain the deformation due to swelling and vehicle loading. The methodology including comparison the differential settlement of the soil stabilized column supported flexible pavement and unsupported flexible pavement as control model. The numerical analysis was modeled using finite element method. The simulations result that the column installation to support flexible pavement reduced the heaving and differential settlement of the pavement effectively. In case the overlay was performed for rehabilitation and maintenance of the pavement, the mini-columns can be installed before the overlay works. However, the conclusions of the study were limited to the result of numerical modeling that depended on the applied material model and volumetric swelling.

scholarly journals Influence de sollicitations hydriques et mécaniques complexes sur le comportement d'un sol gonflant compacté

2005 ◽  
Vol 42 (3) ◽  
pp. 731-741 ◽  
Author(s):  
Olivier Cuisinier ◽  
Farimah Masrouri
Keyword(s):  
Mechanical Loading ◽  
Past History ◽  
Expansive Soil ◽  
Stress Path ◽  
Soil Suction ◽  
Initial Sample ◽  
Plastic Compression ◽  
Solution Methods ◽  
Hydromechanical Behaviour ◽  
Compression Line

The main objective of the paper is to present a study on compacted expansive soil strains generated by complex hydric or mechanical loadings and their consequences on tested soil compressibility. In the first part of the paper, the suction-controlled testing devices are described (osmotic and salt solution methods). All the presented tests were performed in the range of suctions between 0 and 40 MPa. The consequences of the strains induced by wetting as a function of the applied mechanical stress were analyzed. The results showed that, under these conditions, strain depends on the followed hydraulic path, whereas the slope of the plastic compression line λ(s) was only affected by the suction applied during the mechanical loading. The second test series demonstrated that the stress path influenced both deformation and slope λ(s) if suction higher than the initial sample suction was imposed during the test. As a conclusion, it could be stated that the slope λ(s) depends on the suction applied during a mechanical loading and on the maximum suction experienced by an expansive material during its past "history".Key words: compacted soil, suction, hydric cycle, hydromechanical behaviour, expansive soil.

scholarly journals Factors Affecting the Swelling-Compression Characteristics of Clays in Yichang, China

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Changxi Huang ◽  
Xinghua Wang ◽  
Hao Zhou ◽  
Yan Liang
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Expansive Soil ◽  
Swelling Pressure ◽  
Stress Path ◽  
Dry Density ◽  
Initial Water Content ◽  
Initial Water ◽  
Swelling Properties ◽  
Vertical Loading

Expansive soil has been studied for eighty decades because it is prone to cause geotechnical engineering accidents. The results of the moisture content effects on the expansive pressure were not consistent in the literatures. In this paper, swelling deformation and pressure tests were conducted to clarify the effects of the initial water content on the swelling properties. The relation of expansive stress and initial moisture content was accurately described with a Gaussian distribution, unlike in the previously published studies. These results could be explained by the change in the microstructure with diverse moisture contents. In addition, dry density and vertical stress influences on expansive properties were analysed. With an increase in the vertical loading, the soil samples first expanded, and then the samples with a lower dry density collapsed; however, the samples with a higher dry density did not collapse, even under a considerable vertical loading. Furthermore, the relation between stress path and expansive pressure was examined. It was observed that the swelling pressures obtained from the constant volume tests were greater than the results from the swell under load tests. The relationship between the swelling pressure and swelling strain was also analysed.

scholarly journals Mechanical Properties of Soft Soil considering the Influence of Unloading Stress Paths

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Wei Huang ◽  
Junjie Li ◽  
Yuming Lu ◽  
Dongsheng Li ◽  
Yaqing Mou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Numerical Analysis ◽  
Soft Soil ◽  
Strain Curve ◽  
Friction Angle ◽  
Confining Pressure ◽  
Stress Path ◽  
Hyperbolic Function ◽  
Mechanical Parameters ◽  
Current Design

The mechanical properties of soft soil are crucial for the design and construction of underground space excavation; however, the current design and numerical analysis of underground spaces consider the loading mechanical parameters, ignoring the influence of the unloading stress path resulting in frequent construction accidents in practice. Here, soft soil in Shenzhen, China, is taken as the research subject, and a series of consolidated-undrained unloading tests are performed. First, K0 consolidation is conducted. Then, unloading tests are performed with different unloading ratios to simulate different unloading stress paths. The test results show that the soft soil deformation characteristics are closely related to the stress path and unloading ratio. Under different unloading ratios, soft soil will undergo compression deformation or rebound deformation. Under unloading conditions, the deviator stress-strain curve satisfies a hyperbolic function and can be normalized with the average consolidation confining pressure. With the increase in the unloading ratio, the initial tangent modulus first decreases and then increases, the cohesion decreases, and the internal friction angle does not change significantly. The loading mechanical parameters are not suitable for numerical calculation in unloading engineering. In this paper, more unloading paths are considered, such as UU1.0 and UU0.5. The results of the study provide a theoretical basis for the calculation of the numerical analysis of the soil body at different depths in rich soft soil pits.

Numerical Analysis of Combined Bending and Torsion of a Work-Hardening Plastic Square Bar

1967 ◽  
Vol 34 (4) ◽  
pp. 1005-1010 ◽  
Author(s):  
P. M. Miller ◽  
L. E. Malvern
Keyword(s):  
Numerical Analysis ◽  
Iterative Scheme ◽  
Unit Length ◽  
Stress Path ◽  
Computational Effort ◽  
Total Strain ◽  
Isotropic Hardening ◽  
Combined Stress ◽  
Entire Cross Section ◽  
Stress Free State

An iterative scheme using a backward difference in the timelike variable is developed, which makes possible a numerical-analysis solution for the incremental plasticity theory formulation with hardly any extra computational effort than that required for total-strain theory; this permits easy comparison between the predictions of the two theories for a variety of bending-twist histories. Isotropic hardening is assumed, using comparable generalizations of the Ramberg-Osgood stress-strain law to combined-stress incremental and total-strain theories, for continuous loading with no unloading, and for a material assumed to have no initial elastic range, so that the entire cross section is plastic. Analysis, of a uniform prismatic square bar, continuously loaded from a stress-free state, by a bending couple in a plane of symmetry, and a twisting couple, shows that the predictions of the two theories agree when the ratio of curvature to angle of twist per unit length is held constant during the deformation, even though the stress path in stress space is nonradial. When the ratio of curvature to unit angle of twist varies during the deformation, the two theories predict different results.

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