Research on the Retention Capacity of Ruins Soil under Drying Condition

2014 ◽  
Vol 580-583 ◽  
pp. 705-710
Author(s):  
Ping Liu ◽  
Hu Yuan Zhang ◽  
Yi Chen ◽  
Xian Xian Shao ◽  
Xin Yuan Fu
Keyword(s):  
Water Content ◽  
Void Ratio ◽  
Characteristic Curve ◽  
Matric Suction ◽  
Soil Samples ◽  
Degree Of Saturation ◽  
Drying Process ◽  
Retention Capacity ◽  
Pore Water Pressures ◽  
The Relationship

The soil water characteristic curve (SWCC) has been tested during the drying process. In order to define the relationship between suction, degree of saturation and void ratio, fitting models of SWCC was established. Studies have shown that the shape of SWCC of three kinds of samples (taken from Jiaohe, Gaochang and Jiuzhoutai) was similar to the inverted “S”, the relationship between water content and matric suction was inversely proportional. Under the condition of the same moisture, the matric suction of the Jiaohe and Gaochang samples were greater than the Jiuzhoutai samples, and the changes of pore water pressures showed the same trend. The degree of saturation began to decrease when the water content reduced to the air entry value. When the degree of saturation was greater than 90%, the volume of soil samples contracted significantly, and when saturation is below 80%, volume shrinkage stopped.

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.

Using time domain reflectometry in triaxial testing

2000 ◽  
Vol 37 (6) ◽  
pp. 1325-1331
Author(s):  
J LH Grozic ◽  
M E Lefebvre ◽  
P K Robertson ◽  
N R Morgenstern
Keyword(s):  
Cyclic Loading ◽  
Water Content ◽  
Time Domain ◽  
Void Ratio ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Degree Of Saturation ◽  
Triaxial Testing ◽  
Empirical Correlations ◽  
Static And Cyclic Loading

Time domain reflectometry (TDR) can be used to determine the volumetric water content of soils. This note describes the utilization of a TDR miniprobe in triaxial testing. The TDR performance was examined with a series of tests that not only proved its reliability but also resulted in two empirical correlations. Using these correlations, the degree of saturation and volumetric water content during triaxial testing could be determined. The TDR was then put to use in a laboratory program designed to investigate the response of loose gassy sand under static and cyclic loading. Because of the TDR measurements it was possible to determine the degree of saturation and void ratio of the gassy specimens. The TDR miniprobe proved to be accurate, simple to use, and inexpensive to build.Key words: time domain reflectometry, TDR, triaxial testing, gassy, unsaturated.

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.

Laboratory test investigations on soil water characteristic curve and air permeability of municipal solid waste

2018 ◽  
Vol 36 (5) ◽  
pp. 463-470 ◽  
Author(s):  
Jianyong Shi ◽  
Xun Wu ◽  
Yingbo Ai ◽  
Zhen Zhang
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Water Content ◽  
Permeability Coefficient ◽  
Inflection Point ◽  
Void Ratio ◽  
Characteristic Curve ◽  
Air Permeability ◽  
Residual Water ◽  
Residual Water Content

The air permeability coefficient has a high correlation with the water content of municipal solid waste. In this study, continuous drying methodology using a tension meter was employed to construct the soil water characteristic curve of municipal solid waste (M-SWCC). The municipal solid waste air permeability test was conducted by a newly designed apparatus. The measured M-SWCC was well reproduced by the van Genuchten (V-G) model and was used to predict the parameters of typical points in M-SWCC, including saturated water content, field capacity, residual water content and water content at the inflection point. It was found that the M-SWCC was significantly influenced by void ratio. The final evaporation and test period of M-SWCC increase with the increase in void ratio of municipal solid waste. The evolution of air permeability coefficient with water content of municipal solid waste depicted three distinct characteristic stages. It was observed that the water contents that corresponded to the two cut-off points of the three stages were residual water content and water content at the inflection point, respectively. The air permeability coefficient of municipal solid waste decreased with the increase of the water content from zero to the residual water content. The air permeability coefficient was almost invariable when the water content increased from residual water content to the water content at the inflection point. When the water content of municipal solid waste exceeded the water content at the inflection point, the air permeability coefficient sharply decreased with the increase of water content.

Impacts of matric suction equalization on small strain shear modulus of soils during air drying

2020 ◽  
Vol 57 (12) ◽  
pp. 1982-1997
Author(s):  
Thang Pham Ngoc ◽  
Behzad Fatahi ◽  
Hadi Khabbaz ◽  
Daichao Sheng
Keyword(s):  
Shear Modulus ◽  
Water Content ◽  
Soil Sample ◽  
Closed System ◽  
Small Strain ◽  
Matric Suction ◽  
Drying Process ◽  
Air Drying ◽  
Small Strain Shear Modulus ◽  
The Impact

In this study, a weight-control bender element system has been developed to investigate the impact of matric suction equalization on the measurement of small strain shear modulus (Gmax) during an air-drying process. The setup employed is capable of measuring the shear wave velocity and the corresponding Gmax of the soil sample in either an open system in which the soil sample evaporates freely or in a closed system that allows the process of matric suction equalization. The comparison between measurements of Gmax in the open and closed systems revealed underestimations of Gmax when matric suction equalization was ignored due to the nonuniform distribution of water content across the sample cross-sectional area. This study also investigated the time required for matric suction equalization tse to be established for samples with different sizes. The experimental results indicated two main mechanisms driving the matric suction equalization in a closed system during an air-drying process, namely the hydraulic flow of water and the flow of vapour. While the former played the key role when the micropores were still saturated at the high range of water content, effects of the latter increased and finally dominated when more air invaded the micropores at lower water contents.

Study on the Compressibility of the Silt in Hangzhou, China

2013 ◽  
Vol 419 ◽  
pp. 853-857
Author(s):  
Zhen Ying Zhang ◽  
Da Zhi Wu ◽  
Cha Wang
Keyword(s):  
Laboratory Tests ◽  
Void Ratio ◽  
Soil Mechanics ◽  
Soil Samples ◽  
Compression Index ◽  
Uniformity Coefficient ◽  
Initial Void Ratio ◽  
Natural Density ◽  
Engineering Parameters ◽  
The Relationship

To investigate the compressibility of the silt, three soil samples are collected from Xiasha zone, Hangzhou, Zhejiang Province, China. The geotechnical engineering parameters of the silt soil are measured in the soil mechanics laboratory. Tests results show that the uniformity coefficient of the silt is 13.6, the natural density is 1.96t/m3, the moisture content is 17.0%, the plasticity index is 9.4, the compression coefficient varies from 0.06 to 0.40MPa-1, and the compression index varies from 0.015 to 0.108. Finally, the properties of the compression are studied, and find that the compressibility of the silt soil is very large, and the relationship between the initial void ratio and the logarithm pressure is linear.

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.

scholarly journals Investigation into water retention behaviour of deformable soils

2013 ◽  
Vol 50 (2) ◽  
pp. 200-208 ◽  
Author(s):  
Simon Salager ◽  
Mathieu Nuth ◽  
Alessio Ferrari ◽  
Lyesse Laloui
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Void Ratio ◽  
Degree Of Saturation ◽  
Retention Data ◽  
Soil Water Retention ◽  
Retention Behaviour ◽  
Wide Range ◽  
Water Retention Behaviour

The paper presents an experimental and modelling approach for the soil-water retention behaviour of two deformable soils. The objective is to investigate the physical mechanisms that govern the soil-water retention properties and to propose a constitutive framework for the soil-water retention curve accounting for the initial state of compaction and deformability of soils. A granular soil and a clayey soil were subjected to drying over a wide range of suctions so that the residual state of saturation could be attained. Different initial densities were tested for each material. The soil-water retention curves (SWRCs) obtained are synthesized and compared in terms of water content, void ratio, and degree of saturation, and are expressed as a function of the total suction. The studies enable assessment of the effect of the past and present soil deformation on the shape of the curves. The void ratio exerts a clear influence on the air-entry value, revealing that the breakthrough of air into the pores of the soil is more arduous in denser states. In the plane of water content versus suction, the experimental results highlight the fact that from a certain value of suction, the retention curves corresponding to different densities of the same soil are convergent. The observed features of behaviour are conceptualized into a modelling framework expressing the evolution of the degree of saturation as a function of suction. The proposed retention model makes use of the theory of elastoplasticity and can thus be generalized into a hysteretic model applicable to drying–wetting cycles. The calibration of the model requires the experimental retention data for two initial void ratios. The prediction of tests for further ranges of void ratios proves to be accurate, which supports the adequacy of formulated concepts.

Variation of Initial Soil Suction with Compaction Conditions for Clayey Soils

2012 ◽  
Vol 28 (3) ◽  
pp. 431-437 ◽  
Author(s):  
S.-R. Yang ◽  
H.-D. Lin ◽  
W.-H. Huang
Keyword(s):  
Water Content ◽  
Clay Fraction ◽  
Degree Of Saturation ◽  
Soil Suction ◽  
Clayey Soils ◽  
Test Results ◽  
Wide Range ◽  
Initial Soil ◽  
Compaction Energy ◽  
The Relationship

AbstractIn this study, the initial soil suction of as-compacted clayey soils was evaluated for various compaction conditions, covering a wide range of compaction energy and molding water content. The soil specimens were prepared by impact compaction under three levels of compaction energy. The filter paper method was used to measure the initial soil suction of as-compacted specimens. Test results indicate that the relationship between the soil suction and the molding water content is bilinear under three different compaction energies. However, the effect of compaction energy on soil suction is different for the soils with different amounts of clay fraction and is elucidated by the macro soil properties. The change of soil suction due to different compaction energies can be predicted by the void ratio and the degree of saturation.

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