Study on the Test of Soil Water Characteristic Curve

2011 ◽  
Vol 261-263 ◽  
pp. 1094-1098
Author(s):  
Yu You Yang ◽  
Qin Xi Zhang ◽  
Gui He Wang ◽  
Chen Liu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Mathematic Model ◽  
Matric Suction ◽  
Engineering Properties ◽  
Soil Water Characteristic Curve ◽  
Van Genuchten Model ◽  
The Relationship

The test of soil water characteristic curve (SWCC) and its mathematic model are present. The SWCC can describe the relationship between unsaturated soil matric suction and water content. Matric suction is an important parameter to address when studying the engineering properties of unsaturated soil. And while the measurement of substrate attraction is a very difficult issue, it is also one of the biggest obstacles in the engineering applications of unsaturated soil. By analyzing and researching the test data of SWCC researchers can initially establish the mathematic model which is the SWCC equation. The Van Genuchten model and the Fredlund and Xing model were used to simulate better the changes between the volume water content and the matric suction. Predictions were compared with experimental results to determine the simulation capability of the model for the soil of Beijing.

Soil Water Characteristic Curve and its Applications in Tunnel

2011 ◽  
Vol 261-263 ◽  
pp. 1039-1043
Author(s):  
Yu You Yang ◽  
Qin Xi Zhang ◽  
Gui He Wang ◽  
Jia Xing Yu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Land Subsidence ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Tunnel Construction ◽  
Coupling Theory ◽  
Engineering Analysis ◽  
Soil Water Characteristic Curve ◽  
The Relationship

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.

scholarly journals Study on Soil Water and Suction Stress Characteristics for Unsaturated Clay Soil of Airport Engineering Based on Laboratory Tests

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jun Feng ◽  
Guangze Zhang
Keyword(s):  
Soil Water ◽  
Unsaturated Soil ◽  
Triaxial Test ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Deviatoric Stress ◽  
Soil Water Characteristic Curve ◽  
Suction Stress ◽  
Suction Control ◽  
Van Genuchten Model

For the unsaturated soil in Feidong China, this study examined the suction stress characteristics based on the soil-water characteristic curve (SWCC), which was different from traditional research ideas. At the same time, the unsaturated consolidation device was adopted for SWCC tests, with consideration of the influence of yielding stress of soil, which was different from the traditional test approach of the soil-water characteristic curve. The results were estimated using the van Genuchten model, which was revealed that this is well-fit for the studied unsaturated soil, and the triaxial shear-strength tests were conducted with suction control. Then, the suction stress characteristic curve (SSCC) was analyzed, and SWCC-predicted data were compared with triaxial test-derived suction stress data. For the studied unsaturated soil, the deviatoric stress increased with the net inner stress p − u a at the same matric suction. At the same net inner pressure, the deviatoric stress increased with the matric suction, which verified the hardening activity of matric suction on the tested unsaturated soil strength. Besides, triaxial test-derived suction stress data greatly conformed to SWCC data-derived SSCC that was determined using identical parameters used in the SWCC model.

The Study of Correction Method for Soil-Water Characteristic Curve of Swelling-Shrinking Soil

2013 ◽  
Vol 712-715 ◽  
pp. 873-876
Author(s):  
Peng Du ◽  
Xiao Ling Liu ◽  
Xiao Ying Li
Keyword(s):  
Soil Water ◽  
Volume Fraction ◽  
Characteristic Curve ◽  
Correction Method ◽  
Matric Suction ◽  
Engineering Properties ◽  
Water Volume ◽  
Volume Deformation ◽  
Water Volume Fraction ◽  
The Relationship

The swelling-shrinking soil embodies the features of expanding when absorbing water and shrinking when drying out; its engineering properties are sensitive to water fluctuation. Mainstream test instruments of SWCC cannot accurately get its relationship between matric suction and water volume fraction. So a correction method based on the results of shrinkage test is carried out. The method is accomplished by using the volume deformation which is obtained in shrinkage test to calculate its real water volume fraction and then combining the results of SWCC test and finally constructing the relationship between matric suction and water volume fraction. Through real application, this method is proved to be feasible and essential.

Model for the prediction of shear strength with respect to soil suction

1996 ◽  
Vol 33 (3) ◽  
pp. 379-392 ◽  
Author(s):  
S K Vanapalli ◽  
D G Fredlund ◽  
D E Pufahl ◽  
A W Clifton
Keyword(s):  
Shear Strength ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Experimental Studies ◽  
Matric Suction ◽  
Glacial Till ◽  
Soil Suction ◽  
Soil Water Characteristic Curve

Experimental studies on unsaturated soils are generally costly, time-consuming, and difficult to conduct. Shear strength data from the research literature suggests that there is a nonlinear increase in strength as the soil desaturates as a result of an increase in matric suction. Since the shear strength of an unsaturated soil is strongly related to the amount of water in the voids of the soil, and therefore to matric suction, it is postulated that the shear strength of an unsaturated soil should also bear a relationship to the soil-water characteristic curve. This paper describes the relationship between the soil-water characteristic curve and the shear strength of an unsaturated soil with respect to matric suction. Am empirical, analytical model is developed to predict the shear strength in terms of soil suction. The formulation makes use of the soil-water characteristic curve and the saturated shear strength parameters. The results of the model developed for predicting the shear strength are compared with experimental results for a glacial till. The shear strength of statically compacted glacial till specimens was measured using a modified direct shear apparatus. Specimens were prepared at three different water contents and densities (i.e., corresponding to dry of optimum, and wet of optimum conditions). Various net normal stresses and matric suctions were applied to the specimens. There is a good correlation between the predicted and measured values of shear strength for the unsaturated soil. Key words: soil-water characteristic curve, shear strength, unsaturated soil, soil suction, matric suction.

Predicting the permeability function for unsaturated soils using the soil-water characteristic curve

1994 ◽  
Vol 31 (4) ◽  
pp. 533-546 ◽  
Author(s):  
D.G. Fredlund ◽  
Anqing Xing ◽  
Shangyan Huang
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Characteristic Curve ◽  
Degree Of Saturation ◽  
Residual Water ◽  
Soil Water Characteristic Curve ◽  
Coefficient Of Permeability ◽  
Permeability Function

The coefficient of permeability for an unsaturated soil is primarily determined by the pore-size distribution of the soil and can be predicted from the soil-water characteristic curve. A general equation, which describes the soil-water characteristic curve over the entire suction range (i.e., from 0 to 106 kPa), was proposed by the first two authors in another paper. This equation is used to predict the coefficient of permeability for unsaturated soils. By using this equation, an evaluation of the residual water content is no longer required in the prediction of the coefficient of permeability. The proposed permeability function is an integration form of the suction versus water content relationship. The proposed equation has been best fit with example data from the literature where both the soil-water characteristic curve and the coefficient of permeability were measured. The fit between the data and the theory was excellent. It was found that the integration can be done from zero water content to the saturated water content. Therefore, it is possible to use the normalized water content (volumetric or gravimetric) or the degree of saturation data versus suction in the prediction of the permeability function. Key words : coefficient of permeability, soil-water characteristic curve, unsaturated soil, water content, soil suction.

Elastoplastic model for unsaturated soil with incorporation of the soil-water characteristic curve

2007 ◽  
Vol 44 (1) ◽  
pp. 67-77 ◽  
Author(s):  
Trinh Minh Thu ◽  
Harianto Rahardjo ◽  
Eng-Choon Leong
Keyword(s):  
Soil Water ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Rate Of Change ◽  
Soil Parameters ◽  
Published Data ◽  
Elastoplastic Model ◽  
Soil Water Characteristic Curve ◽  
Isotropic Consolidation

An elastoplastic model is proposed in this paper that incorporates the soil-water characteristic curve (SWCC) for obtaining soil parameters of unsaturated soil. The SWCC is shown to govern the rate of change in the soil parameters for the elastoplastic model with respect to matric suction. A series of isotropic consolidation tests under different matric suctions and tests for obtaining SWCC were carried out on statically compacted kaolin specimens. Nanyang Technological University (NTU) mini suction probes were installed along the height of the specimen to measure pore-water pressures during isotropic consolidation and SWCC tests. The results of isotropic consolidation tests demonstrate the strong influence of matric suction on compressibility and stiffness of the soil specimens. The experiments were also simulated using the proposed elastoplastic model and SWCC of the compacted kaolin. The simulated results agree closely with the experimental results. In addition, the proposed elastoplastic model was also verified against published data from the literature.Key words: matric suction, yield surface, soil-water characteristic curve, mini suction probe, elastoplastic model, unsaturated soil.

Experimental Research of Matrix Suction of the Unsaturated Red Clay

2014 ◽  
Vol 919-921 ◽  
pp. 835-838 ◽  
Author(s):  
Wen Feng Zhao ◽  
Long Li ◽  
Yu Hang Xiao
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Matric Suction ◽  
High Water Content ◽  
Dry Density ◽  
Red Clay ◽  
Soil Water Characteristic Curve ◽  
Matrix Suction ◽  
The Impact

Matric suction has great impact on the strength of soil. Some physico-mechanical indexes, such as the water content, dry density of soil, have close relationship with the matric suction. The experiments were conducted in the laboratory to study the relationship between the matric suction, the water content and dry density of unsaturated red clay. The filter paper method was used to get the soil-water characteristic curve of the unsaturated red clay. The results show that: water content has great impact on matrix suction. The soil-water characteristic curve can be divided into three stages. In low water content area, matrix suction decreases rapidly with the increase of water content.Then, the rate of change slows down after the inflection point. Matrix suction increases obviously with the increase of dry density under the condition of low water content, but the impact disappears under high water content. So the matrix suction is affected by dry density and water content.

Study on the Tests of Soil-Water Characteristic Curves of Unsaturated Soil

2013 ◽  
Vol 353-356 ◽  
pp. 16-19
Author(s):  
Xian Chun Zheng ◽  
Fang Zhao ◽  
Si Zhong Sun
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Unsaturated Soil ◽  
Characteristic Curve ◽  
Initial Water Content ◽  
Initial Water ◽  
Soil Water Characteristic Curve ◽  
The Matrix ◽  
Practical Engineering ◽  
Matrix Suction

Soil-water characteristic curve is used to describe the matrix suction and water content of the curve of the relationship between volume, according to the soil-water characteristic curve can be deduced the unsaturated soil shear strength, permeability coefficient, etc., this paper gives the different initial water content and different types of soil, soil-water characteristic curve for practical engineering foundation reinforcement to provide reference.

The Experiment on Soil Water Characteristic Curve Considering the Effect of Urea Concentration

2014 ◽  
Vol 919-921 ◽  
pp. 795-799
Author(s):  
Gai Qing Dai ◽  
Dong Fang Tian ◽  
Yao Ruan ◽  
Lang Tian ◽  
You Le Wang
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Urea Concentration ◽  
Test Method ◽  
Materials Selection ◽  
Valuable Data ◽  
Soil Water Characteristic Curve ◽  
Concentration Test ◽  
The Impact

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.

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