To see the other types of publications on this topic, follow the link: Soil water characteristic curve (SWCC).
Journal articles on the topic 'Soil water characteristic curve (SWCC)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Soil water characteristic curve (SWCC).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Fredlund, Delwyn G., Daichao Sheng, and Jidong Zhao. "Estimation of soil suction from the soil-water characteristic curve." Canadian Geotechnical Journal 48, no. 2 (February 2011): 186–98. http://dx.doi.org/10.1139/t10-060.
Full textAbstract:
Soil-water characteristic curves (SWCCs) are routinely used for the estimation of unsaturated soil property functions (e.g., permeability functions, water storage functions, shear strength functions, and thermal property functions). This paper examines the possibility of using the SWCC for the estimation of in situ soil suction. The paper focuses on the limitations of estimating soil suctions from the SWCC and also suggests a context under which soil suction estimations should be used. The potential range of estimated suction values is known to be large because of hysteresis between drying and wetting SWCCs. For this, and other reasons, the estimation of in situ suctions from the SWCC has been discouraged. However, a framework is suggested in this paper for estimating the median value for in situ soil suction along with a likely range of soil suction values (i.e., maximum and minimum values). The percentage error in the estimation of soil suction from the SWCC is shown to be lowest for sand soils and highest for clay soils.
2
Li, J. H., L. M. Zhang, and X. Li. "Soil-water characteristic curve and permeability function for unsaturated cracked soil." Canadian Geotechnical Journal 48, no. 7 (July 2011): 1010–31. http://dx.doi.org/10.1139/t11-027.
Full textAbstract:
Cracks are widely present in natural and engineered soils. As water infiltration into a cracked soil often starts from unsaturated conditions, the soil-water characteristic curve (SWCC) and permeability function for the cracked soil are required when conducting seepage analysis. This paper presents a method to predict the SWCC and permeability function for cracked soil considering crack volume changes during drying–wetting processes. The cracked soil is viewed as an overlapping continuum of a crack network system and a soil matrix system. The pore-size distributions for the two pore systems at a particular state can be determined and used to estimate the SWCCs and permeability functions. The estimated SWCCs and permeability functions for the two pore systems can be combined to give the SWCC and the permeability function for the cracked soil at that state. Then, the SWCC and permeability function for the cracked soil at different states along a crack development path can be obtained and combined to give the SWCC or permeability function for the cracked soil considering crack volume changes. Examples are presented to illustrate the prediction of the SWCCs and permeability functions for a cracked soil along five crack development paths.
3
Thu, Trinh Minh, Harianto Rahardjo, and Eng-Choon Leong. "Soil-water characteristic curve and consolidation behavior for a compacted silt." Canadian Geotechnical Journal 44, no. 3 (March 1, 2007): 266–75. http://dx.doi.org/10.1139/t06-114.
Full textAbstract:
Measurement of the soil-water characteristic curve (SWCC) in the laboratory is commonly conducted under zero confining pressure. However, in the field, the soil is under a confining stress. Therefore, it is important to study the effects of the confining stress on SWCC. In addition, the consolidation curve is normally generated under saturated conditions. However, the soil above the water table is usually unsaturated. Hence, it is also necessary to investigate the effects of matric suction on the characteristics of the consolidation curves. This paper presents the SWCCs under different net confining stresses and the isotropic consolidation curves under different matric suctions that describe the volume change characteristics of unsaturated soils with respect to stress state variables, net normal stress, and matric suction. A series of SWCCs was determined for statically compacted silt specimens in a triaxial cell apparatus under different net confining stresses. Isotropic consolidation tests under different matric suctions were also carried out. The results of the SWCC tests show that the air-entry value increased with increasing net confining stress. The yield points (i.e., yield suction, s0) obtained from the SWCC tests also increased with increasing net confining stress. The results of isotropic consolidation tests indicate the strong influence of matric suction on compressibility and stiffness of the compacted silt specimens.Key words: soil-water characteristic curve, isotropic consolidation, pore-water pressure, volume change, NTU mini suction probe, matric suction.
4
Yang, Hong, Harianto Rahardjo, Eng-Choon Leong, and D. G. Fredlund. "Factors affecting drying and wetting soil-water characteristic curves of sandy soils." Canadian Geotechnical Journal 41, no. 5 (September 1, 2004): 908–20. http://dx.doi.org/10.1139/t04-042.
Full textAbstract:
Drying and wetting soil-water characteristic curves (SWCCs) for five sandy soils are investigated using a Tempe pressure cell and capillary rise open tube. The test data are fitted to two SWCC equations using a least-squares algorithm. The obtained fitting parameters and some hysteretic behaviour are discussed and correlated with grain-size distribution parameters. A concept of total hysteresis is proposed to quantify the hysteresis of SWCC. The measured SWCC for one soil is also compared with the SWCC estimated from its grain-size distribution. The SWCC was also obtained at a high dry density for one of the soils. The results show that the shapes of the SWCCs are similar to the grain-size distributions of the soils and are affected by the dry density of the soil. A coarse-grained soil has a lower air-entry value, residual matric suction, and water-entry value and less total hysteresis than a fine-grained soil. The residual matric suction and water-entry value tend to approach the same value when the effective grain size D10 of the soil is small, in the range of 3-6 mm. SWCCs of uniform soils have steeper slopes and less total hysteresis than those of less uniform soils. Soils with a low dry density have a lower air-entry value and residual matric suction than soils with a high dry density. The SWCC predicted from grain-size distribution is found to be sufficiently accurate.Key words: soil-water characteristic curve, water content, suction, hysteresis, grain size.
5
Satyanaga, Alfrendo, Jong Kim, Sung-Woo Moon, and Martin Wijaya. "Exponential Functions for Modelling Hysteresis of Soil-Water Characteristic Curves." E3S Web of Conferences 195 (2020): 02002. http://dx.doi.org/10.1051/e3sconf/202019502002.
Full textAbstract:
Soil – water characteristic curve (SWCC) is an important property of unsaturated soils that can be used to estimate various parameters to describe unsaturated soil behavior. SWCC is reported to be hysteretic because the water content at a given suction in the wetting process is less than that in the drying process. In order to simulate the hysteretic characteristics of SWCC, many models have been proposed by different researchers. However, majority of the existing models are complex and their parameters are not related to the physical significances of SWCC variables. In this study, the new equations are developed to model drying and wetting SWCC. In addition, some indexes are proposed to estimate the wetting SWCC from drying SWCC. The new equations for SWCCs were evaluated with the laboratory data from published literatures. The results showed that the proposed equations performed well in modelling drying and wetting SWCC. The new equation has less parameters than the existing published equation.
6
Abbaszadeh, Mohammad M., and Sandra L. Houston. "Influence of Soil Cracking on the Soil-Water Characteristic Curve of Clay Soil." Soils and Rocks 38, no. 1 (January 1, 2015): 49–58. http://dx.doi.org/10.28927/sr.381049.
Full textAbstract:
The hydraulic conductivity for unsaturated soil conditions is more difficult to estimate than for the saturated condition. In addition, as the soil transitions from intact to cracked, the difficulty in estimating the unsaturated hydraulic conductivity increases. One critical step in the determination of unsaturated flow hydraulic conductivity is the evaluation of the Soil-Water Characteristic Curve (SWCC). In this paper, a series of laboratory studies of direct measurements of cracked soil SWCCs is presented, including challenges associated with the control of very low suction levels associated with crack dewatering. An oedometer-type SWCC apparatus, capable of suction and net normal stress control, and volume change measurement, was used in these experimental studies. It is common that SWCCs are comprised of matric suction values below about 1500 kPa, and total suction values for suctions higher than about 1500 kPa (Fredlund et al., 2012). In this study, all measured or controlled suction values were less than 1500 kPa and obtained using the axis translation method, and the curve in the higher suction range was projected by forcing the SWCC through 106 kPa for completely dried conditions (Fredlund et al., 2012). Volume change corrections were made to the reported volumetric water contents, which is of particular importance when the soil under consideration undergoes volume change in response to wetting or drying. A technique for the determination of the SWCC for cracked clay soils is presented. Test results validated the fact that the SWCC of a cracked soil can be represented by a bimodal function due to the Air Entry Value (AEV) of the cracks being much lower than the AEV of the soil matrix. It was also found that differences between the SWCC for cracked and intact soil appears only in the very low suction range.
7
Xu, Xu, Fu You Zhang, and Ming Gu. "Experimental Research on Soil-Water Characteristic Curve of Unsaturated Soils." Applied Mechanics and Materials 353-356 (August 2013): 554–57. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.554.
Full textAbstract:
The soil-water characteristic curve (SWCC) reflects water storage capacity, Measuring it accurately is important in engineering. This paper concluded main factors of SWCC, measured soil-water characteristic of loess under conditions of different dry densities, the curve of volume water content, saturation and matric suction were presented, the curves showed similar change trend, saturation mainly determined the matric suction when matric suction was small.
8
Syarifudin, Achmad, and Alfrendo Satyanaga. "Variability of Bimodal Soil-Water Characteristic Curves under Different Confining Pressures." Applied and Environmental Soil Science 2021 (June 5, 2021): 1–10. http://dx.doi.org/10.1155/2021/5569491.
Full textAbstract:
Soils with two subcurves of Soil-Water Characteristic Curve (SWCC) (dual porosity soils) might be found within various residual soils. Soils located in different depths have different confining pressure. Residual soils are found in the unsaturated zones due to the deep groundwater table. There is a linear correlation between the hydraulic properties of the soil in the unsaturated area and that of its unsaturated properties. This study aims to examine the influence of the confining pressure towards the SWCC of dual porosity soil. The scope of this study involves measurements of the drying and wetting SWCC using Tempe cells, pressure plates, and an advanced triaxial apparatus. In this study, the mathematical equations were developed to explain the effect of confining pressure on SWCC. The experimental results indicated that the dual porosity soil exhibits bimodal characteristics for the drying curve of SWCC and it exhibits unimodal characteristics for the wetting curve of SWCC. As the confining pressure increases, the air entry values, the inflection points, and the standard deviation of drying SWCC increase. In addition, the hysteresis of SWCC is becoming smaller with the increasing confining pressure.
9
Ramos-Rivera, Johnatan, Daniel Parra-Holguín, Yamile Valencia-González, and Oscar Echeverri-Ramírez. "Estimating soil-water characteristic curve based on soil type and best-fitting regressions derived from a simplified method using Aburra Valley dataset." MATEC Web of Conferences 337 (2021): 02002. http://dx.doi.org/10.1051/matecconf/202133702002.
Full textAbstract:
In unsaturated soil mechanics, many attempts have been made to estimate the SWCC based on soil texture and grain-size distribution. This paper proposes a simplified method to estimate the soil-water characteristic curve (SWCC) for both coarse and fine-grained soils using SWCC data and machine learning computer code in the Aburra Valley. Fredlund and Xing parameters has been used to estimate the SWCC correlations. Soil samples collected from field survey were subjected to laboratory testing, SWCCs were estimated using filter paper method. Each SWCC data set from Aburra Valley was fitted with Fredlund and Xing curve using multiple regression analysis, correlations were derived for those four parameters based on predictors derived from machine learning. The proposed method gives a good estimation and low residual errors of the SWCC.
10
Schafer, Haley, and Nicholas Beier. "Estimating soil-water characteristic curve from soil-freezing characteristic curve for mine waste tailings using time domain reflectometry." Canadian Geotechnical Journal 57, no. 1 (January 2020): 73–84. http://dx.doi.org/10.1139/cgj-2018-0145.
Full textAbstract:
The unsaturated properties of a soil are required to predict the rate of dewatering and magnitude of strength gain of a mine waste tailings deposit during desiccation dewatering. This prediction requires the soil-water characteristic curve (SWCC), which is time-consuming and challenging to attain and may take anywhere from weeks to months to complete a single test. As a result, alternative methods are needed to estimate the SWCC. Past research has indicated that the soil-freezing characteristic curve (SFCC) can be used to estimate the SWCC in some soils. An experimental method and apparatus were developed to measure the SFCC to estimate the SWCC for different mine waste tailings, including copper tailings, gold tailings, and oil sands centrifuge cake. The experimental method involved using a resistance temperature detector to measure the temperature and time domain reflectometry to determine the unfrozen water content of the soil. The results showed that the SFCC could be used to estimate the SWCC for tailings from metal mines (gold tailings and copper tailings) with a high portion of sand-sized particles and a small amount of clay-sized particles, but was not able to estimate the SWCC for oil sands tailings.
11
NASCIMENTO, ÍCARO VASCONCELOS DO, THIAGO LEITE DE ALENCAR, CARLOS LEVI ANASTÁCIO DOS SANTOS, RAIMUNDO NONATO DE ASSIS JÚNIOR, and JAEDSON CLÁUDIO ANUNCIATO MOTA. "EFFECT OF SAMPLE RE-SATURATION ON SOIL-WATER CHARACTERISTIC CURVE." Revista Caatinga 31, no. 2 (June 2018): 446–54. http://dx.doi.org/10.1590/1983-21252018v31n221rc.
Full textAbstract:
ABSTRACT Soil-water characteristic curve (SWCC) is an important tool for water management in irrigated agriculture. However, factors such as texture and structure of soils influence SWCC behavior. According to the literature, wetting and drying cycles alter SWCC. A similar process of re-saturation and drying occurs during SWCC obtainment under laboratory conditions. Based on the hypothesis that re-saturation process alters SWCC due to clay loss in the sample, this study aimed to obtain the SWCC, S index, and pore size distribution from samples submitted to re-saturation cycles, as well as from not re-saturated samples but under higher matric potentials (-2, -4, -6, -8, and -10 kPa). For this, disturbed and undisturbed soil samples, collected from the A (sandy texture) and Btg (sandy clay loam texture) horizons of a Argissolo Acizentado, were used. After obtaining SWCC, each air-dried soil sample was submitted to particle size and clay dispersed in water analyses to verify whether the soil lost clay. The experimental design was a completely randomized design with two methods of SWCC constructing (with and without re-saturation) and eight replications. The re-saturation process generates a loss of clay in the sample, not causing significant changes in SWCC considering the assessed textural soil classes. In addition, sandy soil samples are more sensitive to changes in pore size distribution when submitted to re-saturation.
12
Yang, Chunliu, Jianhua Wu, Peiyue Li, Yuanhang Wang, and Ningning Yang. "Evaluation of Soil-Water Characteristic Curves for Different Textural Soils Using Fractal Analysis." Water 15, no. 4 (February 15, 2023): 772. http://dx.doi.org/10.3390/w15040772.
Full textAbstract:
The soil-water characteristic curve (SWCC) is an essential tool to determine hydraulic and mechanical properties of unsaturated soils. As an inherent influencing factor, soil texture controls the characteristics of SWCCs. Fractal theory can quantitatively describe the physical characteristics of soil. This study used particle size distribution data and water content data contained in the UNSODA2.0 database to explore the fractal characteristics of 12 soil types with different textures under different matrix suctions. The SWCC fractal model was adopted to characterize the hydraulic properties of soil with various soil textures. The findings revealed that the mass fractal dimensions of particles from these 12 different soil types significantly differed and were closely related to the clay content. Fractal dimension increased with increasing clay content. The fractal dimension established a good relationship between soil structure and hydraulic properties. Fractal analysis can be used to determine the connection between physical properties and soil hydraulic parameters. The estimated results of the SWCC fractal model indicated that it had a good performance regarding the description of SWCCs for the 12 soil textures. The soil structure could be described through fractal dimensions, which can effectively indicate soil hydraulic characteristics. The estimated fractal dimension of this model could be obtained by particle size distribution. Furthermore, using the SWCC fractal model, we found that the SWCC of coarse textured soil changed sharply in the low suction stage and its residual water content was small, and the SWCC of fine textured soil changed gently with a large residual water content. The water retention capacity followed the order clay > silty clay > sandy clay > clay loam > silty clay loam > sandy clay loam > loam > silt loam > sandy loam > silt > loamy sand > sand.
13
Chin, Kheng-Boon, Eng-Choon Leong, and Harianto Rahardjo. "A simplified method to estimate the soil-water characteristic curve." Canadian Geotechnical Journal 47, no. 12 (December 2010): 1382–400. http://dx.doi.org/10.1139/t10-033.
Full textAbstract:
This paper proposes a simplified method to estimate the soil-water characteristic curve (SWCC) for both coarse- and fine-grained soils using one-point SWCC measurement and basic index properties. Parameters of the Fredlund and Xing SWCC equation were correlated with the basic properties of 60 soils: 30 soils each of coarse- and fine-grained types. Sensitivity analysis revealed that the location of the one-point measurement at matric suctions of 10 and 500 kPa gave the most reliable SWCC using the proposed method for coarse- and fine-grained soils, respectively. The validity of the proposed method was evaluated using a total of 62 soils collated from published literature with 31 soils each of the coarse- and fine-grained types. The proposed method gives a good estimation of the SWCC and uses fewer parameters when compared with existing one-point SWCC estimation methods.
14
Yan, Wei, Emanuel Birle, and Roberto Cudmani. "A simple approach for predicting soil water characteristic curve of clayey soils using pore size distribution data." MATEC Web of Conferences 337 (2021): 02012. http://dx.doi.org/10.1051/matecconf/202133702012.
Full textAbstract:
The soil water characteristic curve (SWCC) of soils can be derived from the measured pore size distribution (PSD) data by applying capillary models. This method is limited for clayey soils due to the PSD changes during SWCC testing. In this study, a suction-dependent multimodal PSD model based on probability theory is developed and used to derive SWCC. The model is validated by simulating the drying branches of SWCCs of four compacted Lias Clay samples with different initial states. A good consistency between the measured and predicted SWCC is shown.
15
Peranić, Josip, Željko Arbanas, Sabatino Cuomo, and Matej Maček. "Soil-Water Characteristic Curve of Residual Soil from a Flysch Rock Mass." Geofluids 2018 (July 29, 2018): 1–15. http://dx.doi.org/10.1155/2018/6297819.
Full textAbstract:
Depending on the nature of the material and suction range, laboratory measurements of the soil-water characteristic curve (SWCC) can be time-consuming and expensive, especially for residual soils, in which a wide range of particle sizes and soil structures typically results in SWCCs that cover a wide range of suction. Investigations of the SWCCs of residual soil from flysch rock masses are rare, and so far, no results were presented in the literature which were obtained by performing measurements on undisturbed specimens. In this paper, a detailed examination of water retention characteristics is performed for a specific type of residual soil (CL) formed by the weathering of a flysch rock mass. Measurements performed by using different techniques and devices on intact specimens were successfully combined to obtain the SWCC during both drying and wetting processes, under different stress conditions, and from saturated to air-dried conditions. Used procedures are suitable for the determination of SWCCs of soils that undergo volume changes during the drying or the wetting process, since instantaneous volumetric water content can be determined. Results presented in this paper can be used to assess the influence of desaturation of the residual soil covering flysch slopes during dry summer periods by providing key-in material properties required to analyze the transient rainfall infiltration process.
16
Okovido, J. O., and E. O. Obroku. "Soil water characteristic curve of a compacted A-7-5 tropical red earth soil." Nigerian Journal of Technology 40, no. 3 (October 20, 2021): 379–86. http://dx.doi.org/10.4314/njt.v40i3.4.
Full textAbstract:
Soil water characteristic curve (SWCC) is a very important property of unsaturated soil and by extension tropical red earth soils. This is because several other important soils’ properties can be related to it. The Filter paper method was employed in the determination of the A-7-5(5) tropical red earth WCC. The gravimetric water content was utilized in the computation of the SWCC. Four models, Fredlund and Xing (1994), FX; Van Genuchten (1980), VG; Brooks and Corey (1964), BC; and Kosugi (1996), K were used to estimate the SWCCs of the soil and the minimum SSEnorm (MSSE), Average Relative Error (ARE), and R2 values were used to determine the most suitable model for predicting the SWCC. Results show that all four models can be used to predict A-7-5(5) WCC as they all had R2 value greater than 89% although BC and K models perform best with coefficient of determination of over 97%. MSSE and ARE% were also significantly low for BC and K models.
17
Habasimbi, Paul, and Tomoyoshi Nishimura. "Comparison of Soil–Water Characteristic Curves in One-Dimensional and Isotropic Stress Conditions." Soil Systems 2, no. 3 (July 26, 2018): 43. http://dx.doi.org/10.3390/soilsystems2030043.
Full textAbstract:
Understanding unsaturated soil behavior is key to the design of foundations and embankment structures. Geotechnical engineers have applied net normal stress and matric suction to these engineering problems. Water retention activity in soils is used to predict seepage problems and stability of slope failures. Soil–Water Characteristic Curve (SWCC) tests contribute largely to matric suction interpretation. Determination of SWCCs in the laboratory is usually done using a pressure plate apparatus where vertical or confining stress cannot be applied. Mathematical models of SWCC though commonly accepted in geotechnical engineering practices, do not take into consideration stress conditions such as the difference between a one-dimensional condition and isotropic confining conditions. This study conducted SWCC tests of a silt soil under one-dimensional and isotropic confining stress conditions and focused on the differences between these types of SWCC data sets. Vertical and isotropic confining stresses ranging from 100 to 600 kPa were applied under both stress conditions. SWCCs appears to be affected by the influence of different stress conditions. Lateral pressure and confinement on an isotropic compression condition caused the soil specimen to become dense in void structure and consequently, soil moisture flow movement decreased. This probably induced high retention activities in the silt soil specimen. The study further suggests that the current SWCC models require further development to take into consideration the effect of different stress conditions.
18
Xie, Xiao, Ping Li, Xiaokun Hou, Tonglu Li, and Guowei Zhang. "Microstructure of Compacted Loess and Its Influence on the Soil-Water Characteristic Curve." Advances in Materials Science and Engineering 2020 (January 8, 2020): 1–12. http://dx.doi.org/10.1155/2020/3402607.
Full textAbstract:
Soil-water characteristic curve (SWCC) is a key constitutive relationship for studying unsaturated soil, and as is known, microstructure of the soil has great influence on the mechanical behaviour of the soil. In this study, the wetting and drying soil-water characteristic curves (SWCCs) of loess compacted at three different water contents were measured using the filter paper method. And microproperties of compacted loess were obtained by the mercury intrusion method (MIP) and scanning electron microscope (SEM). Results show that the compaction water contents have significant influence on the SWCC and microstructure. The pore size distribution (PSD) curves have great differences in macropore range and are similar in micropore range. Loess compacted at optimum and dry of optimum are generally connected, while there are certain number of nonintruded pores in loess compacted at wet of optimum. The SWCC curves vary significantly in low suction (ua − uw < 1000 kPa) and tend to converge together in high suction (ua − uw ≥ 1000 kPa). Hysteresis in the SWCCs is more obvious for loess compacted at optimum and dry of optimum in the matric suction of 0∼100 kPa; however, there is a pronounced hysteresis for loess compacted at wet of optimum in full matric suction range. The characteristic of the SWCCs including their hysteresis can be well interpreted from the loess microstructure.
19
Fredlund, Murray D., G. Ward Wilson, and Delwyn G. Fredlund. "Use of the grain-size distribution for estimation of the soil-water characteristic curve." Canadian Geotechnical Journal 39, no. 5 (October 1, 2002): 1103–17. http://dx.doi.org/10.1139/t02-049.
Full textAbstract:
The implementation of unsaturated soil mechanics into engineering practice is dependent, to a large extent, upon an ability to estimate unsaturated soil property functions. The soil-water characteristic curve (SWCC), along with the saturated soil properties, has proven to provide a satisfactory basis for estimating the permeability function and shear strength functions for an unsaturated soil. The volume change functions have not been totally defined nor applied in geotechnical engineering. The objective of this paper is to present a procedure for estimating the SWCC from information on the grain-size distribution and the volumemass properties of a soil. SWCCs represent a continuous water content versus soil suction relationship. The proposed method provides an approximate means of estimating the desorption curve corresponding to a soil initially slurried near the liquid limit. The effects of stress history, fabric, confining pressure, and hysteresis are not addressed. A database of published data is used to verify the proposed procedure. The database contains independent measurements of the grain-size distribution and the SWCC. The level of fit between the estimated and measured SWCCs is analyzed statistically. The proposed procedure is compared to previously proposed methods for predicting the SWCC from the grain-size distribution. The results show that the proposed procedure is somewhat superior to previous methods.Key words: soil-water characteristic curve, grain-size distribution, volume-mass properties, pedo-transfer function, unsaturated soil property functions.
20
Li, Xiong Wei, Yong Wang, and Xiao Shu Jiang. "Predicting Reservoir Pressure with Soil-Water Characteristic Curve." Advanced Materials Research 1073-1076 (December 2014): 2215–18. http://dx.doi.org/10.4028/www.scientific.net/amr.1073-1076.2215.
Full textAbstract:
Experiment study on shallow gassy unsaturated sand under different confining pressure with GDS triaxial system's 4D stress path module is carried out. Different SWCC shapes under different confining pressures are analyzed. The results show that unsaturated sand's water retention capacity declines gradually with confining pressure infliction and accretion. Finally, shallow gassy sand's gas reservoir pressure characteristics with SWCC are analyzed and forecast, and it's conservative if the same thing is done based on SWCC without confining pressure.
21
Fang, Xiang Wei, Shu Ping Jiang, Chun Ni Shen, Yun Xie, and Gang Li. "Influences of Deviatoric Stress on the Soil-Water Characteristic Curve." Advanced Materials Research 243-249 (May 2011): 2456–59. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2456.
Full textAbstract:
The soil-water characteristic curve (SWCC) is one of the major research subjects in unsaturated soil mechanics. To study the influence of deviatoric stress on the SWCC of an unsaturated soil, a series of triaxial drained shear tests by controlling constant net mean stress and suction were conducted. It was found that the SWCC was dependent on deviatoric stress. A unified SWCC equation was proposed including not only water content and suction, but also net mean stress and deviatoric stress.
22
Zhang, Junhui, Junhui Peng, Yejuan Chen, Jue Li, and Feng Li. "Estimation of Soil-Water Characteristic Curve for Cohesive Soils with Methylene Blue Value." Advances in Civil Engineering 2018 (July 5, 2018): 1–7. http://dx.doi.org/10.1155/2018/9213674.
Full textAbstract:
This study described a new methylene blue test to measure the methylene blue value (MBV) for 15 cohesive soils and established the relationship between MBV and plasticity index (PI) and between MBV and percent passing No. 200 sieve (P200), respectively. Thereafter, the soil-water characteristic curves (SWCCs) for 15 cohesive soils based on Fredlund and Xing’s model were generated by the pressure plate test. Then, regression equations for determining the four fitting parameters in a previously developed SWCC equation by using the measured MBV were utilized to generate the SWCC for the cohesive soils. At the same time, the slope parameter, bf, in the SWCC equations was found to be associated with the moisture susceptibility of cohesive soils. A higher bf value indicates that the material is more moisture susceptible. In addition, a lower MBV/PI/P200 shows a lower suction at the same degree of saturation; on the other hand, a higher MBV/PI/P200 presents a higher suction. Therefore, the moisture-holding capacity of cohesive soils increases with increasing MBV, PI, and P200. Finally, the proposed estimation method was validated by a comparison between the four determined fitting parameters from MBV and the pressure plate test.
23
Yang, Yu You, Qin Xi Zhang, Gui He Wang, and Chen Liu. "Study on the Test of Soil Water Characteristic Curve." Advanced Materials Research 261-263 (May 2011): 1094–98. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1094.
Full textAbstract:
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.
24
Angelaki, Anastasia, Vasiliki Bota, and Iraklis Chalkidis. "Estimation of Hydraulic Parameters from the Soil Water Characteristic Curve." Sustainability 15, no. 8 (April 15, 2023): 6714. http://dx.doi.org/10.3390/su15086714.
Full textAbstract:
Soil water characteristic curve (SWCC) is one of the most essential hydraulic properties that play fundamental role in various environmental issues and water management. SWCC gives important information for water movement, soil behavior, infiltration, and drainage mechanism, affecting the water circle and the aquifer recharge. Since most of the world’s freshwater withdrawals go for irrigation uses, decoding SWCC is beneficial, as it affects water saving through irrigation planning. Estimation of crucial parameters, such as field capacity (FC) and permanent wilting point (PWP) is the key solution for water saving. Modelling of the SWCC and hydraulic parameters estimation are of great importance, since the laboratory experimental procedures and the experiments in the field are often time-consuming processes. In the present study, the SWCC along with FC and PWP of two soil types were obtained via specific experimental procedures in the laboratory. In order to simulate the SWCC and estimate FC and PWP, the experimental data were approximated with van Genuchten’s model. Results showed that using SWCC to estimate FC gives excellent results, while the method rationally overestimates the PWP. Hence, the presented method leads to estimation of crucial hydraulic parameters that can be used in irrigation planning and water saving practices.
25
Alowaisy, Adel, Noriyuki Yasufuku, Ryohei Ishikura, Masanori Hatakeyama, and Shuu Kyono. "Novel rapid measurement system of undisturbed soils water characteristics curve utilizing the continuous pressurization method." E3S Web of Conferences 92 (2019): 07008. http://dx.doi.org/10.1051/e3sconf/20199207008.
Full textAbstract:
Through this paper, a sampling methodology and a novel full automatic system adopting the continuous pressurization method which is capable of determining the Soil Water Characteristics Curve (SWCC) for both remoulded and undisturbed samples in a very short time were developed. The proposed system was validated by comparing the SWCCs of standard testing soils obtained using the developed system to the SWCCs obtained using a conventional method. Remoulded and undisturbed natural soil samples were tested, where the degree of disturbance influence on the obtained SWCC was discussed. In addition, the undisturbed samples containing moulds material influence on the obtained SWCC was investigated. It was found that remoulded samples do not properly represent the in-situ conditions with significant error that should be carefully considered when conducting analysis and proposing countermeasures against unsaturated soils related Geo-disasters. In addition, the material which the containing mould is made from has minor influence on the obtained SWCC which can be neglected. Finally, it can be concluded that the developed undisturbed soil water characteristics curve obtaining system is direct, rapid, reliable and simple. In addition, the proposed undisturbed sampling and testing methodology can be used to accurately evaluate the spatial variations of the SWCC regardless the heterogeneity of the soil profile.
26
Wang, You Le, Dong Fang Tian, Gai Qing Dai, Yao Ruan, and Lang Tian. "A Soil Water Characteristic Curve Model Considering Urea Concentration." Advanced Materials Research 798-799 (September 2013): 157–60. http://dx.doi.org/10.4028/www.scientific.net/amr.798-799.157.
Full textAbstract:
A new soil water characteristic curve (SWCC) model considering urea concentration is presented in the paper. Two assumptions are used to obtain the model. One is SWCC which could be described by exponential functions in the experiments. Another is relationship between the parameters of exponential functions and urea concentration which is linear based on experimental data. In the research, we have carried out 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.
27
Zainal, Abdul-Kareem Esmat, and Shaimaa Hasan Fadhil. "Prediction of soil water characteristic curve using artificial neural network: a new approach." MATEC Web of Conferences 162 (2018): 01014. http://dx.doi.org/10.1051/matecconf/201816201014.
Full textAbstract:
Soil-Water Characteristic Curve (SWCC) is an important relationship between matric suction and volumetric water content of soils especially when dealing with unsaturated soil problems, these problems may include seepage, bearing capacity, volume change, etc. where the matric or total suction may have a considerable effect on unsaturated soil properties. Obtaining an accurate SWCC for a soil could be cumbersome and sometimes it is time consuming and needs effort for some soils, either through laboratory tests or through field tests. Accurate prediction of this curve can give more precise expectations in design or analysis that include some unsaturated soil properties, which can save more effort and time. This work will concentrate on proposing a new approach for determining the SWCC using Artificial Neural Network (ANN) depending on some soil properties (air-entry point and residual degree of saturation) through computer software MatLab as a tool for ANN. The new approach is to plot the SWCC curve points instead of obtaining the parameters used in Brooks and Corey (BC) Model (1964), van Genuchten (VG) Model (1980), or Fredlund and Xing (FX) Model (1994). Results showed close agreement in determination of the SWCC by verification of the ANN results with an additional curve sample.
28
Matlan, Siti Jahara, Muhammad Mukhlisin, and Mohd Raihan Taha. "Performance Evaluation of Four-Parameter Models of the Soil-Water Characteristic Curve." Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/569851.
Full textAbstract:
Soil-water characteristic curves (SWCCs) are important in terms of groundwater recharge, agriculture, and soil chemistry. These relationships are also of considerable value in geotechnical and geoenvironmental engineering. Their measurement, however, is difficult, expensive, and time-consuming. Many empirical models have been developed to describe the SWCC. Statistical assessment of soil-water characteristic curve models found that exponential-based model equations were the most difficult to fit and generally provided the poorest fit to the soil-water characteristic data. In this paper, an exponential-based model is devised to describe the SWCC. The modified equation is similar to those previously reported by Gardner (1956) but includes exponential variable. Verification was performed with 24 independent data sets for a wide range of soil textures. Prediction results were compared with the most widely used models to assess the model’s performance. It was proven that the exponential-based equation of the modified model provided greater flexibility and a better fit to data on various types of soil.
29
Wang, Lin, Wengang Zhang, and Fuyong Chen. "Bayesian Approach for Predicting Soil-Water Characteristic Curve from Particle-Size Distribution Data." Energies 12, no. 15 (August 2, 2019): 2992. http://dx.doi.org/10.3390/en12152992.
Full textAbstract:
Soil-water characteristic curve (SWCC) is a significant prerequisite for slope stability analysis involving unsaturated soils. However, it is difficult to measure an entire SWCC over a wide suction range using in-situ or laboratory tests. As an alternative, the Arya and Paris (AP) model provides a feasible way to predict SWCC from the routinely available particle-size distribution (PSD) data by introducing a scaling parameter. The accuracy of AP model is generally dependent on the calibrated database which contains test data collected from other sites. How to use the available test data to determine the scaling parameter and to predict the SWCC remains an unresolved problem. This paper develops a Bayesian approach to predict SWCC from PSD. The proposed approach not only determines the scaling parameter, but also identifies fitting parameters of the parametric SWCC model. Finally, the proposed approach is illustrated using real data in Unsaturated Soil Database (UNSODA). Results show that the proposed approach provides a proper prediction of SWCC by making use of the available test data. Additionally, the proposed approach is capable of predicting SWCC in the high suction range, allowing engineers to obtain a complete SWCC in practice with reasonable accuracy.
30
Oh, Won-Taek, and Mahsa Bajestani. "Effect of Soil-Water Characteristic Curve on the Stability of Unsupported Vertical Trenches in Unsaturated Soils." E3S Web of Conferences 382 (2023): 13002. http://dx.doi.org/10.1051/e3sconf/202338213002.
Full textAbstract:
In geotechnical engineering practice, unsupported vertical trenches are typically excavated in unsaturated soils. In this case, the variation of shear strength and hydraulic conductivity with respect to soil suction is key information to analyze the stability of an unsupported vertical trench. Most shear strength and hydraulic conductivity models use the soil-water characteristic curve (SWCC) as a main tool. Various models are available to determine SWCC, shear strength, and hydraulic conductivity for unsaturated soils. Scholars or practitioners use one the existing models in numerical analyses to estimate the stability of unsupported vertical trench considering rainfall events. However, limited studies have been undertaken to investigate the effect of SWCC and hydraulic conductivity functions on the stability of unsupported vertical trenches in unsaturated soils. In the present study, numerical stability analyses are carried out by using different SWCCs and hydraulic conductivity functions to investigate their influence on the estimated safe height and stand-up time of unsupported vertical trenches. The same shear strength model was used for entire numerical analyses.
31
Castro, Cíntia, Anderson Soares, and Marcos Aguiar. "Soil-water characteristic curve of polypropylene fibrereinforced sandy soil." Soils and Rocks 45, no. 3 (July 15, 2022): 1–9. http://dx.doi.org/10.28927/sr.2022.070021.
Full textAbstract:
Fibre reinforcement is considered a good alternative for improving the geotechnical properties of soil. However, studies that investigate its behaviour, accounting for the unsaturated condition, and the hydraulic behaviour of soil mixtures with fibre, are limited. Therefore, the current study evaluates the impact of the inclusion of polypropylene fibres on the hydraulic behaviour of soil through geotechnical characterisation, scanning electron microscopy (SEM), macroporosity and microporosity tests, and filter paper tests. The soil-water characteristic curve (SWCC) of different mixtures of fibre-reinforced soil was adjusted by the models enshrined in the literature, using polypropylene fibres of length 6 mm, diameter 18 μm, and fibre contents 0.25% (SF025), 0.75% (SF075), 1.0% (SF100), and 1.25% (SF125) relative to the dry weight of the soil. The results indicated a transition from unimodal to bimodal shape in the SWCC for the polypropylene fibre-reinforcement, suggesting that their inclusion altered the soil structure. The same bimodal behaviour of SWCC was observed in all reinforced samples that produced similar values of air-entry suction and residual volumetric water content, but with increased water retention for the same level of suction for higher fibre content. The results of the tension table test indicated an increase in the volume of macropores with an increase in fibre content and a decrease in micropore volumes. These results agree with the compaction tests, which showed a decrease in the dry maximum density with an increased fibre content, whereas the optimum water content increased.
32
V A Alexander, Damian, Kyung Ho Park, and Derek Anthony Gay. "An estimation of the soil water characteristics curves of Trinidad's expansive clays." E3S Web of Conferences 195 (2020): 03009. http://dx.doi.org/10.1051/e3sconf/202019503009.
Full textAbstract:
Volume change behaviour of expansive clays has been one of the leading causes of damage to civil infrastructures worldwide. Contributing factors that lead to failures relate to changes in water content within the soil. Variations of water content can vary significantly based on an area’s climate regime. Trinidad has two seasons, the dry season (January to June) and the wet season (July to December). This variation leads to volume changes of expansive clay, where they exist mainly within the central and south regions of Trinidad. These areas are densely populated by residential and commercial buildings, which can be susceptible to damages from unsaturated expansive clays. The Soil Water Characteristic Curve (SWCC) for expansive clays is critical to estimate their unsaturated properties for the analysis of water flow movement. This study investigates the SWCCs for two expansive clay soil types in Trinidad. A WP4-T (Water Potential Measurement) is used to measure soil suction. The shrinkage curve (SC) test is conducted to consider the volume change of soil. The Fredlund and Xing (1994) SWCC equation and Fredlund and Zhang (2013) SC equation are used to fit the measured data. The SWCCs in terms of gravimetric and volumetric water contents and degree of saturation are compared. It is found that the normalised degree of saturation SWCC can provide a better display of the SWCC and estimation of the air-entry value.
33
Guo-Quan, Ding, Bian Xia, Yuan Jun-Ping, and Zhu Jun-Gao. "Bimodal SWCC and Bimodal PSD of Soils with Dual-Porosity Structure." Mathematical Problems in Engineering 2022 (June 24, 2022): 1–10. http://dx.doi.org/10.1155/2022/4052956.
Full textAbstract:
The soil–water characteristic curve (SWCC) and pore-size distribution (PSD) are fundamental characteristics of soils that determine many physical and mechanical properties. Recent studies demonstrate that both SWCC and PSD sometimes exhibit a bimodal feature. In this paper, soils with bimodal SWCCs are mainly divided into three categories: gap-graded soils, compacted clayey soils, and natural dual-porosity structural soils, from the perspective of microporosity structure. Based on the Fredlund and Xing unimodal SWCC equation, a bimodal SWCC equation is presented. The bimodal PSD equation d v / d log r for mercury intrusion porosimetry (MIP) is derived theoretically, according to the relationship between the mercury intrusion process in MIP and the water desorption process along the drying SWCC. These two associated equations have the same set of parameters, so the corresponding relationship between the bimodal SWCC and bimodal PSD can be directly shown. Three main presenting forms of PSD in MIP tests are summarized. Regression analysis results show that the proposed PSD equation can well fit bimodal PSD experimental data of various soils in the literature, and the SWCCs are predicted at the same time.
34
Yi, Fa Cheng, Zhe Wang, and Min Juan Zhou. "Research on the Soil Water Characteristic Curve and Prediction of Compacted Bentonite." Advanced Materials Research 518-523 (May 2012): 2785–91. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.2785.
Full textAbstract:
In this paper, the soil water characteristic curve (SWCC)of Xinjiang Altay bentonite under different stress states, different initial dry density and different initial water content has been tested by dialysis method and vapor phase method, and the impact of the various factors on the water retention characteristics of Xinjiang Altay bentonite has been analyzed comprehensively. The mercury intrusion porosimetry (MIP) test has been carried out on the soil sample, and then the SWCC is predicted by the Pore size distribution(PSD)curve which is got from the MIP test. Finally, the predicted SWCC is compared with the measured SWCC, and it shows that the predicted SWCC is close to the measured values, but there are deviations in the high suction.
35
Thu, Trinh Minh, Harianto Rahardjo, and Eng-Choon Leong. "Elastoplastic model for unsaturated soil with incorporation of the soil-water characteristic curve." Canadian Geotechnical Journal 44, no. 1 (January 1, 2007): 67–77. http://dx.doi.org/10.1139/t06-091.
Full textAbstract:
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.
36
Yang, Yu You, Qin Xi Zhang, Gui He Wang, and Jia Xing Yu. "Soil Water Characteristic Curve and its Applications in Tunnel." Advanced Materials Research 261-263 (May 2011): 1039–43. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1039.
Full textAbstract:
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.
37
Zhou, Jie, Junjie Ren, and Zeyao Li. "An Improved Prediction Method of Soil-Water Characteristic Curve by Geometrical Derivation and Empirical Equation." Mathematical Problems in Engineering 2021 (June 17, 2021): 1–22. http://dx.doi.org/10.1155/2021/9956824.
Full textAbstract:
Much attention has been paid on the soil-water characteristic curve (SWCC) during decades because it plays great roles in unsaturated soil mechanics. However, it is time-consuming and costly to obtain a series of entire saturation-suction data by experiments. The curves acquired by directly fitting empirical equations to limited experimental data are greatly different from the actual SWCC, and the relevant soil parameters obtained by inaccurate curve are also incorrect. Thus, an improved prediction method for more accurate entire SWCC was established. This novel method was based on the analysis of shape characteristics of SWCC with three critical points S , C 1 , and C 2 under the hypothesis of geometrical symmetric relation. The theoretical computation was specifically deduced under conventional Gardner, VG, and FX models, respectively, and then inferred on different soil types of 45 collected SWCC datasets. This geometrical symmetric relation exhibited well in all these three conventional empirical equations, especially in Gardner equation. Finally, a series of filer paper tests on sand, silt, and clay were also carried out to acquire entire SWCC curve for the verification and evaluation of the proposed geometrical method. Results show that this improved prediction method effectively decreases deviation resulting from directly fitting empirical equations to limited data of wide types of soils. The averaged improvement was larger under VG equation than under Gardner and FX equation. It proved that the accuracy of predicting greatly depends on the shape characteristic point of maximum curve curvature (point C 2 ), other than the number of points. This research provides a novel computation method to improve prediction accuracy even under relative less experimental data.
38
Han, Zhong, Sai K. Vanapalli, and Wei-lie Zou. "Integrated approaches for predicting soil-water characteristic curve and resilient modulus of compacted fine-grained subgrade soils." Canadian Geotechnical Journal 54, no. 5 (May 2017): 646–63. http://dx.doi.org/10.1139/cgj-2016-0349.
Full textAbstract:
This paper combines a series of approaches for predicting the soil-water characteristic curve (SWCC) and the variation of the resilient modulus (MR) of compacted fine-grained subgrade soils with moisture content, which is the key information required in mechanistic pavement design methods. The presented approaches for the SWCC and MR are integrated, as (i) they are developed following the same philosophy, (ii) they require only the measurements of the suction and moisture content or MR at saturated and optimum moisture content conditions for prediction, and (iii) the predicted SWCC is used for predicting the MR – moisture content relationship. Experimental studies have been performed on five fine-grained subgrade soils that were collected from different regions in Ontario, Canada, to determine their MR at various external stress levels and post-compaction moisture contents, as well as their SWCCs after the MR tests. Experimental measurements are predicted using the integrated approaches and the empirical approaches currently used in the mechanistic–empirical pavement design guide (MEPDG). It is demonstrated that the integrated approaches are easy to use and show improved reliability in predicting both the SWCC and MR for the investigated subgrade soils in spite of using limited experimental data.
39
Dafalla, M. A., A. M. Al-Mahbashi, A. Almajed, and M. Al-Shamrani. "Predicting Soil-Water Characteristic Curves of Clayey Sand Soils Using Area Computation." Mathematical Problems in Engineering 2020 (June 3, 2020): 1–9. http://dx.doi.org/10.1155/2020/4548912.
Full textAbstract:
The soil-water characteristic curves (SWCCs) for soils are important for geotechnical engineers in the prediction of clay behavior in case of partially saturated conditions. In the wastewater and waste containment industry, variable clay content is considered. It is not practical to run a time-consuming test several times to obtain the soil-water characteristic curves for every proportion. This study is aimed at introducing a practical procedure to predict the response of clay of known mineralogy and geological setting when clay content within a liner is variable. Fitting curves were performed using Fredlund and Xing’s (1994) equations. The general trends were established for selected clay of known high content of smectite minerals. Obtained curves were examined, and areas under the suction curve were integrated from the starting point to the inflection point for clay-sand material with 5%, 10%, 15%, 30%, 60%, and 100% clay content. This area can be used to estimate the profile of the SWCC for higher or lower clay content based on an area factor determined for a specific clay type or clay of known mineralogy. Other clay of similar nature, but not typical mineralogy, were compared in order to observe and validate the use of the area method in predicting the SWCC for similar soils.
40
Zhang, Yuwei, Zhanping Song, Xiaolin Weng, and Yongli Xie. "A New Soil-Water Characteristic Curve Model for Unsaturated Loess Based on Wetting-Induced Pore Deformation." Geofluids 2019 (April 15, 2019): 1–14. http://dx.doi.org/10.1155/2019/1672418.
Full textAbstract:
The soil-water characteristic curve (SWCC) is the basis for describing seepage, strength, and constitutive model of unsaturated soil. The existing SWCC models do not work accurately for evaluating loess, because they do not consider the pore deformation that is induced by wetting. The present study develops a new SWCC model for unsaturated loess. The model considers the effect of wetting-induced pore deformation (WIPD) on the SWCC. The new model includes 6 parameters, which could be confirmed by laboratory tests. The pore volume function (PVF) was described by the WIPD. The shift factor ξ1i and the compression factor ξ2i were introduced into the model. The relationship between the void ratio e and ξ1i and ξ2i was established using the average pore radius. The new SWCC model for saturated loess was improved based on the classical van Genuchten (V-G) model. If the WIPD had not been considered, the new model would regress into the classical V-G model. SWCC tests of unsaturated loess with different void ratios were carried out to verify the new model. The model parameters were calibrated in the original state, and the SWCCs of different void ratios were predicted by the new model and found to be in good agreement with the test results.
41
Tao, Gaoliang, Yin Chen, Henglin Xiao, Qingsheng Chen, and Juan Wan. "Determining Soil-Water Characteristic Curves from Mercury Intrusion Porosimeter Test Data Using Fractal Theory." Energies 12, no. 4 (February 24, 2019): 752. http://dx.doi.org/10.3390/en12040752.
Full textAbstract:
Accurate determination of soil-water characteristic curve (SWCC) is of immense importance for understanding the mechanical behavior of unsaturated soils. Due to the difficulty and long duration of experimental procedures, it is of great significance to estimate the SWCC by indirect methods. To address this issue, in this article an effective fractal method is proposed for predicting the SWCC based on mercury intrusion porosimeter (MIP) data. Only two characteristic parameters, namely the fractal dimension and air-entry value, are needed in the presented approach. Detailed procedures for determining the parameters are clearly elaborated. Due to the influence of sample size difference on the equivalent connected pore size, a sample scale effect coefficient is proposed to predict air-entry values. The concept of “critical pore size” is introduced to obtain the optimal fractal dimension, which can accurately reflect the fractal behaviour of SWCC samples. By comparisons between predicted and experimental SWCCs, the validation of the proposed method is verified. The comparisons reveal the good agreement between the proposed approach and laboratory experiments.
42
Kocaman, Kadir, Askin Ozocak, Tuncer B. Edil, Ertan Bol, Sedat Sert, Kurban Onturk, and Mustafa Ozsagir. "Evaluation of Soil-Water Characteristic Curve and Pore-Size Distribution of Fine-Grained Soils." Water 14, no. 21 (October 29, 2022): 3445. http://dx.doi.org/10.3390/w14213445.
Full textAbstract:
A soil’s physical properties, mineral types, and pore structure significantly influence the shape and properties of the soil-water characteristic curve (SWCC). This study investigated the effects of the soil’s physical properties and mineral types on the SWCC and pore-size distribution (PSD). Eight different soils from an alluvial deposit in Istanbul and Adapazarı/Türkiye were used in the study. The test samples were prepared by compaction at optimum water content (OWC) and wet side of optimum water content (wet of OWC). The samples were prepared by consolidation from the slurry. The PSDs of the samples were calculated using the SWCCs and evaluated with scanning electron microscope (SEM) analysis. In addition, the mineral types of all soils were determined by X-ray diffraction analysis. The soil which contains illite-type minerals has higher matric suction than containing kaolin-type. The effect of the clay percentage is more pronounced in silty soils than in plasticity and activity. Soil suction increased with decreasing compaction water content in clayey soils. The air entry water contents rose as the void ratio, liquid limit, clay content, and plasticity increased. The compaction conditions affected the macropore structure more than the micropore structure. In addition, the ratio of macro-micro pore sizes increased with the rise of the compaction water content.
43
Lizana Olarte, Diego Edson Meliton, Zenón Aguilar-Bardales, and Diana Lucia Calderón-Cahuana. "Estimación de la curva característica suelo agua en suelos arenosos mediante el ensayo de papel filtro." TECNIA 33, no. 1 (August 2, 2023): 52–60. http://dx.doi.org/10.21754/tecnia.v33i1.1397.
Full textAbstract:
The unsaturated soils mechanics is strongly related to the suction phenomenon that occurs between solid soil particles, which changes when the soil water content does not remain constant. The soil-water characteristic curve (SWCC) provides information related to suction and water content of the soil; and to obtain such a curve different direct and indirect methods can be used. In this research the soil-water characteristic curve for sands is obtained through the implementation of the filter paper test. For this purpose, three reconstituted samples of sandy soils from Lima – Peru (relative density between 20% and 60%) were tested following the wet path of the curve. The samples were stored at least seven days until equilibrium was reached. In this way, discrete points of the soil-water characteristic curve were obtained. SWCC equations such as Brooks and Corey (1964), Van Genuchten (1980), and Fredlund and Xing (1994) were used to adjust the data and obtain their respective parameters for sandy soils. Results show that the filter paper test can be used to obtain the soil-water characteristic curves of reconstituted sandy soils; and that the matric suction of sandy soil can be obtained in seven days period by means of this method; whereas a longer storage time could require to reach the equilibrium and to obtain the total suction for these soils.
44
Feng, Jun, and Guangze Zhang. "Study on Soil Water and Suction Stress Characteristics for Unsaturated Clay Soil of Airport Engineering Based on Laboratory Tests." Geofluids 2021 (July 22, 2021): 1–8. http://dx.doi.org/10.1155/2021/5233045.
Full textAbstract:
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.
45
Ahmed, Asif, Md Jobair Bin Alam, Pratibha Pandey, and MD Sahadat Hossain. "Estimation of unsaturated flow parameters and hysteresis curve from field instrumentation." MATEC Web of Conferences 337 (2021): 01008. http://dx.doi.org/10.1051/matecconf/202133701008.
Full textAbstract:
Abstract: The negative pore water pressure or soil suction has significant effect on the performance of geotechnical infrastructures (e.g., slope, pavement, embankment etc.). The unsaturated behavior of soil is not static, rather offers variation in response to climatic loading. The objective of the study was to evaluate field-based techniques of SWCC construction in terms of capturing these variation as compared to laboratory methods and predictive models. The field assessment could allow the quantification of hysteresis effect on the SWCC. Instrumentation data from one Texas, USA highway was used in this study. Soil Water Characteristic Curves (SWCCs) were regenerated utilizing co-located moisture and suction data from the field. Laboratory and field measured SWCCs from the instrumented site were fitted by van Genuchten model. Previously developed predicted models were also utilized to evaluate the SWCC parameters. Based on the evapotranspiration and rainfall amounts, distinct drying and wetting cycles were recorded. Though hourly data was collected in this study, average daily values were used for the analysis. Unsaturated flow parameters (α, n, m) were determined from both laboratory testing and field moisture-suction data along with the predictive models. Clear differences were observed between the values obtained from predictive models and field generated SWCC. The outcome from this study revealed that field reconstructed SWCCs can be used to simulate higher precision in numerical modeling in numerous geotechnical applications.
46
Liu, Shiyu, Noriyuki Yasufuku, Qiang Liu, Kiyoshi Omine, and Hazarika Hemanta. "Bimodal and multimodal descriptions of soil-water characteristic curves for structural soils." Water Science and Technology 67, no. 8 (April 1, 2013): 1740–47. http://dx.doi.org/10.2166/wst.2013.046.
Full textAbstract:
In the last decades several approaches have been developed to describe bimodal or multimodal soil-water characteristic curves (SWCCs). Unfortunately, most of these models were derived empirically. In the presented study, physically based bimodal and multimodal SWCC functions have been developed for structural soils. The model involved two or more continual pore series; the probability density functions for each pore series were assumed to be lognormal distribution and can be superposed to obtain the overall probability density function of the structural soils. The proposed functions were capable of simulating bimodal or multimodal SWCCs using parameters which can be related to physical properties of the structural soils. The experimental SWCC data were used to verify the proposed method. The fitting results showed that the proposed approaches resulted in good agreement between measurement and simulation. These functions can potentially be used as effective tools for indentifying hydraulic porosities in the structural mediums.
47
Carnavale, Thiago de Souza, Ana Carolina de Campos Viana, Paula Morais Canedo de Magalhães, and Tácio Mauro Pereira de Campos. "Soil-water resistivity curve of a tropical soil." MATEC Web of Conferences 337 (2021): 01011. http://dx.doi.org/10.1051/matecconf/202133701011.
Full textAbstract:
The evaluation of soil-water characteristic curve is one of the most important procedures in the matter of understanding the soil behaviour during wetting and drying processes. Even though it might be carried out by established methods, this practice is considered a time-consuming technique, and because of this it is still under-used in comparison with its potential applications. In this way, this paper aims to analyse the correlation of soil suction and soil resistivity to produce a time-reduced soil-water characteristic curve (SWCC), based on resistivity measured values. To perform this research, it was used a set of soil samples collected from Nova Friburgo, Rio de Janeiro – Brazil. The material was geotechnically characterized by standard methods. To determine the (SWCC), it was used the filter paper method and the volumetric water content/suctions were obtained by wetting and drying stages for two paths that emerged from the field moisture content. The results revealed a remarkable relationship between suction and the resistivity measured data, emphasizing the feasibility of determining the Soil-Water Characteristic Curve by resistivity measurements, here named Soil-Water Resistivity Curve (SWResC).
48
Singh, D. N., and Sneha J. Kuriyan. "Estimation of unsaturated hydraulic conductivity using soil suction measurements obtained by an insertion tensiometer." Canadian Geotechnical Journal 40, no. 2 (April 1, 2003): 476–83. http://dx.doi.org/10.1139/t02-112.
Full textAbstract:
To estimate the unsaturated soil hydraulic conductivity of a silty soil, an insertion tensiometer has been used for measuring its suction corresponding to different water contents. These suction values have been used for developing the soil-water characteristic curve (SWCC). The obtained SWCC has been compared with the trends predicted by various fits available in the literature. Further, with the help of the obtained SWCC, the unsaturated soil hydraulic conductivity has been estimated. The study demonstrates the usefulness of insertion tensiometers for measuring soil suction and for estimating its hydraulic conductivity.Key words: silty soil, suction, insertion tensiometer, soil-water characteristic curve, unsaturated soil hydraulic conductivity.
49
Bashir, Rashid, Jitendra Sharma, and Halina Stefaniak. "Effect of hysteresis of soil-water characteristic curves on infiltration under different climatic conditions." Canadian Geotechnical Journal 53, no. 2 (February 2016): 273–84. http://dx.doi.org/10.1139/cgj-2015-0004.
Full textAbstract:
This paper presents results of a numerical modelling exercise that investigates the effects of hysteresis of the soil-water characteristic curve (SWCC) on the infiltration characteristics of soils subjected to four different climatic conditions — from very dry to wet — within the Canadian province of Alberta. Multi-year climate datasets from four different natural regions and subregions of Alberta are compiled, classified, and applied as the soil–atmosphere boundary condition in one-dimensional finite element unsaturated flow models using Hydrus-1D software. Multi-year simulations are carried out with and without consideration of the SWCC hysteresis. Simulation results are analyzed in terms of water balance at the ground surface and temporal distribution and storage of water within the soil domain. It is demonstrated that hysteresis of the SWCC can significantly affect the prediction of flow, redistribution, and storage of water in the unsaturated zone. It is found that for soils that exhibit hysteretic SWCC, consideration of hysteresis in unsaturated flow modelling results in the prediction of lower infiltration and less movement of water through the soil. It is also found that the use of wetting parameters results in the prediction of increased infiltration and movement of water compared with the predictions using drying or hysteretic parameters. It is concluded that, for soils that exhibit a greater degree of SWCC hysteresis, it is important to measure both the drying and wetting branches of the SWCC accurately and that accurate simulation of hysteretic behaviour requires climate datasets at appropriate resolution. The results presented in this paper highlight the importance of considering SWCC hysteresis for a wide range of geotechnical problems, such as soil cover design, prediction of groundwater recharge, contaminant transport through unsaturated soils, soil erosion, slope stability, and swelling–shrinkage of expansive soils.
50
Wang, Ming Wu, Shuai Qin, and Jian Li. "Soil-Water Characteristics of Lime-Treated Expansive Clays in Hefei." Applied Mechanics and Materials 256-259 (December 2012): 558–62. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.558.
Full textAbstract:
Lime treatment technique is a convenient and common method used to improve expansive clays in engineering properties. The soil-water characteristic curve (SWCC) plays a role on engineering features of unsaturated lime-treated expansive clays. Herein, the soil-water characteristic tests by means of GDS and simulations were conducted to investigate the SWCCs of lime-treated expansive clays in Hefei. The results show that lime-treated expansive soil behaves hysteretic characteristics. Under the same value of suction, the higher cell pressure the larger the volumetric water content is. The numerical simulations from Fredlund model do good agreement with tests.