Application of soil-water characteristic curve taking stress influence into considerations in unsaturated seepage analysis

2010 ◽  
pp. 155-160
2011 ◽  
Vol 312-315 ◽  
pp. 1172-1177 ◽  
Author(s):  
A. Topa Gomes ◽  
A. Viana Da Fonseca ◽  
A. Silva Cardoso

The seepage analysis in geotechnical problems, namely in excavations, was typically performed assuming saturated conditions in the ground. It is now know that the flow in the non saturated part of the ground assumes also relevant importance and hence it is vital to characterize its behaviour. The Soil Water Characteristic Curve (SWCC) of the soil is probably the most important parameter in defining this behaviour and particularly for estimating the permeability of the soil. This paper presents the definition of the SWCC for a granite residual soil using pressure plates and the filter paper method. Based on experimental data some equations are adjusted and the results obtained are discussed. At the end of the paper some predictions of the non saturated permeability of the ground are also performed.


2011 ◽  
Vol 94-96 ◽  
pp. 1930-1935
Author(s):  
Zhen Hua Shi ◽  
Zhao Wan Gao

A mathematical model for the soil-water characteristic curve is proposed in the light of bounding surface plasticity. The main drying and wetting curves are taken as the asymptotes of the scanning curves, and only one additional parameter is introduced to simulate such scanning curves. To pave to the way for the application of the proposed model, the governing equation of unsaturated seepage problems and the finite element formulations are derived. A FEM program incorporating the SWCC model is then developed and used to study the hydraulic behaviour of an earth dam undergoes a repeated change of reservoir level. Numerical results confirm the possibility and necessity of using such a hysteresis model in unsaturated seepage problems.


2010 ◽  
Vol 12 (3) ◽  
pp. 336-341
Author(s):  
Fei CAI ◽  
Xiaohou SHAO ◽  
Zhenyu WANG ◽  
Mingyong HUANG ◽  
Yaming ZHAI ◽  
...  

2014 ◽  
Vol 919-921 ◽  
pp. 795-799
Author(s):  
Gai Qing Dai ◽  
Dong Fang Tian ◽  
Yao Ruan ◽  
Lang Tian ◽  
You Le Wang

A new soil water characteristic curve (SWCC) experiment contemplating urea concentration is presented in the paper. We focus on the impact of the SWCC considering urea concentration test method for materials selection and introduction, experimental results, and finally, we have conducted some experiments of SWCC and obtained some valuable data which could affect urea concentration. By using linear fitting, an exponential function between water content and suction and urea concentration is established.


2011 ◽  
Vol 261-263 ◽  
pp. 1039-1043
Author(s):  
Yu You Yang ◽  
Qin Xi Zhang ◽  
Gui He Wang ◽  
Jia Xing Yu

A soil water characteristic curve (SWCC) can describe the relationship between unsaturated soil matric suction and water content. By analyzing and researching the test data of the soil water characteristic curve researchers can initially establish the SWCC equation and apply this equation to the actual engineering analysis. In another words, this article is based on the fluid-solid coupling theory of unsaturated soil used to analyze and study the problem of land subsidence caused by tunnel construction. Numerical calculations show that the coupling results agree well with the measured curve works.


1999 ◽  
Vol 36 (2) ◽  
pp. 363-368 ◽  
Author(s):  
Daud W Rassam ◽  
David J Williams

A relationship describing the shear-strength profile of a desiccating soil deposit is essential for the purpose of analysis, especially when a numerical method is adopted where each zone in a discretised grid is assigned an elevation-dependent shear-strength value. The matric-suction profile of a desiccating soil deposit is nonlinear. Up to the air-entry value, an increase in matric suction is associated with a linear increase in shear strength. Beyond air entry, as the soil starts to desaturate, a nonlinear increase in shear strength occurs. The soil-water characteristic curve is stress dependent, as is the shear-strength gain as matric suction increases. In this paper, a three-dimensional, nonlinear regression analysis showed that a power-additive function is suitable to describe the variation of the shear strength of unsaturated soils with matric suction. The proposed function incorporates the effect of normal stress on the contribution of matric suction to the shear strength.Key words: air-entry value, matric suction, nonlinear regression, soil-water characteristic curve, tailings, unsaturated shear strength.


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