Study on Consolidation Test for Fresh Soft Dredger Fill

2014 ◽  
Vol 501-504 ◽  
pp. 71-74
Author(s):  
Ai Rong Zheng ◽  
Fan Liu ◽  
Ju Chen
Keyword(s):  
Water Content ◽  
Soil Sample ◽  
Deformation Rate ◽  
Inverse Relationship ◽  
Compression Modulus ◽  
Consolidation Test ◽  
Sample Height ◽  
Compressibility Coefficient ◽  
Consolidation Coefficient ◽  
Dredger Fill

The consolidation test was performed to samples of fresh soft dredger fill with heights of 2cm, 3cm and 4cm with full-automatic pneumatic consolidometer. The results show that: the soil sample deforms greatly during the consolidation with significant decrease in water content and small consolidation coefficient. The sample height has negligible effect on the deformation rate, compression modulus, compressibility coefficient, etc., while it is closely related to the consolidation coefficient with an inverse relationship.

Mechanical aspects of rabbit fecal dehydration

1990 ◽  
Vol 258 (3) ◽  
pp. G391-G394 ◽  
Author(s):  
A. T. McKie ◽  
W. Powrie ◽  
R. J. Naftalin
Keyword(s):  
Water Content ◽  
Distal Colon ◽  
Mechanical Pressure ◽  
Physiological Conditions ◽  
Fluid Permeability ◽  
Consolidation Coefficient ◽  
Fecal Water ◽  
Prolonged Retention ◽  
Sufficient Magnitude ◽  
Rabbit Feces

The hydrostatic pressure required to reduce the water content of rabbit feces in an odometer from greater than 80 to less than 65% was approximately 5 atm. This pressure was unaffected by raising the temperature from 20 to 37 degrees C. It became progressively more difficult to dehydrate feces as consolidation occurred, as is evident from the significant (P less than 0.001) reduction in the fecal consolidation coefficient (Co) from 1.76 +/- 0.25 X 10(-6) (n = 4) to 1.35 +/- 0.093 X 10(-7) m2/s (n = 4) and the fecal fluid permeability coefficient (k) from 4.10 +/- 0.51 X 10(-8) (n = 4) to 1.42 +/- 0.12 X 10(-10) m/s (n = 4), concomitant with the reduction in fecal water content. The results suggest that rabbit hard feces are unlikely to be produced, under physiological conditions, by mechanical pressure exerted by the wall of the colon or by a prolonged retention time of hard feces by the distal colon. The hypertonic absorbate (1,000 mosmol/kg) produced by rabbit descending colon is of sufficient magnitude to overcome the fecal resistance to dehydration.

EXPERIMENTAL STUDY ON UNSATURATED DOUBLE-POROSITY SOIL PHENOMENA UNDER VIBRATION EFFECT

2017 ◽  
Vol 79 (4) ◽  
Author(s):  
Loke Kok Foong ◽  
Norhan Abd Rahman ◽  
Ramli Nazir
Keyword(s):  
Water Content ◽  
Soil Sample ◽  
Soil Structure ◽  
Double Porosity ◽  
Dominant Factor ◽  
Response Analysis ◽  
Surface Cracks ◽  
Ground Acceleration ◽  
Small Surface ◽  
Vibration Effect

A physical experiment approach was conducted to observe the deformation of double-porosity soil under vibration effect. The double-porosity soil characteristic was created using kaolin soil. An experiment on a soil sample fitted with accelerometer was conducted on a vibratory table to obtain peak ground acceleration and peak surface acceleration. After the vibration process, the deformable double-porosity soil was verified through field emission scanning electron microscopy tests. As seen in the microscope images, large surface cracks were observed due to the weakness of aggregated kaolin soil structure with its 25% water content. However, the 30% water content soil had small surface cracks due to its stronger soil structure. It was found that the deformable double-porosity soil had more fractured pores compared to the intact soil sample. From the acceleration response analysis, it was seen that both samples had amplification and dis-amplification shaking. In conclusion, the fractured double-porosity, as expected, has high permeability become a dominant factor in fluid migration. Meanwhile, the unconstrained soil and large fracture structure fabric showed significantly different porosity. The percentage of water content plays an important role in the structure of fractured double-porosity soil. 

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.

scholarly journals A QUANTITATIVE EVALUATION OF THE WATER DISTRIBUTION IN A SOIL SAMPLE USING NEUTRON IMAGING

2016 ◽  
Vol 56 (5) ◽  
pp. 388-394 ◽  
Author(s):  
Jan Šácha ◽  
Michal Sněhota ◽  
Jan Hovind
Keyword(s):  
Water Content ◽  
Soil Sample ◽  
Neutron Radiography ◽  
Three Dimensional ◽  
Neutron Imaging ◽  
Water Infiltration ◽  
Water Volume ◽  
Two Dimensional ◽  
Total Water ◽  
Beam Hardening

This paper presents an empirical method by Kang et al. recently proposed for correcting two-dimensional neutron radiography for water quantification in soil. The method was tested on data from neutron imaging of the water infiltration in a soil sample. The raw data were affected by neutron scattering and by beam hardening artefacts. Two strategies for identifying the correction parameters are proposed in this paper. The method has been further developed for the case of three-dimensional neutron tomography. In a related experiment, neutron imaging is used to record ponded-infiltration experiments in two artificial soil samples. Radiograms, i.e., two-dimensional projections of the sample, were acquired during infiltration. A calculation was made of the amount of water and its distribution within the radiograms, in the form of two-dimensional water thickness maps. Tomograms were reconstructed from the corrected and uncorrected water thickness maps to obtain the 3D spatial distribution of the water content within the sample. Without the correction, the beam hardening and the scattering effects overestimated the water content values close to the perimeter of the sample, and at the same time underestimated the values close to the centre of the sample. The total water content of the entire sample was the same in both cases. The empirical correction method presented in this study is a relatively accurate, rapid and simple way to obtain the quantitatively determined water content from two-dimensional and three-dimensional neutron images. However, an independent method for measuring the total water volume in the sample is needed in order to identify the correction parameters.

Uncertainty of One-Dimensional Consolidation of Multi-Layered Soft Clay Soils

2011 ◽  
Vol 250-253 ◽  
pp. 1838-1841
Author(s):  
Xiao Yong Li
Keyword(s):  
Soft Clay ◽  
Compression Modulus ◽  
Probability Characteristic ◽  
Coefficient Of Consolidation ◽  
One Dimensional ◽  
The Monte Carlo Method ◽  
Consolidation Coefficient ◽  
Characteristic Values ◽  
Consolidation Degree ◽  
Substantial Degree

The measured coefficient of consolidation can have a substantial degree of variation even in a uniform clay layer. The probability characteristic values for such parameters as consolidation coefficient and compression modulus are analyzed from local engineering data. This paper, through a probabilistic analysis, examines the variability of one-dimensional consolidation solutions. The multilayer models are evaluated. Then the Monte Carlo method is used to develop solutions for one dimensional consolidation. It identified the influence of the parameter uncertainty on the probability characteristic of the consolidation degree. The uncertainty of consolidation coefficient has a great impact on the probabilistic characteristics of the consolidation degree, but for compression modulus it is opposite true. It proposed a simplification analysis method that considers only the uncertainty of consolidation coefficient without consideration of the uncertainty of compression modulus, and its erroneous precision can meet the engineering requirements.

Estimation of hydraulic conductivity of unsaturated soils using a geotechnical centrifuge

2002 ◽  
Vol 39 (3) ◽  
pp. 684-694 ◽  
Author(s):  
D N Singh ◽  
Sneha J Kuriyan
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Soil Sample ◽  
Unsaturated Soil ◽  
Unsaturated Soils ◽  
Soil Hydraulic Conductivity ◽  
Centrifuge Testing ◽  
Geotechnical Centrifuge ◽  
Silty Soil ◽  
Unsaturated Hydraulic Conductivity

A saturated silty soil sample is centrifuged in a geotechnical centrifuge to create an unsaturated state. The change in water content of the soil sample is recorded at different points along the length of the sample to obtain the water-content profile, which is then used to obtain the unsaturated hydraulic conductivity of the soil sample. These hydraulic conductivity values are compared with those obtained and reported by previous researchers by conducting accelerated falling-head tests on this soil sample in a centrifuge. The study demonstrates the use of centrifugation techniques to obtain hydraulic conductivities of unsaturated soils.Key words: silty soil, saturated soil, unsaturated soil, hydraulic conductivity, centrifuge testing.

scholarly journals Pengaruh Penambahan Abu Serbuk Kayu Dan Serbuk Batu Bata Berdasarkan Uji Konsolidasi Dan Waktu Penurunan Tanah Lempung

2021 ◽  
Vol 9 (2) ◽  
pp. 124-128
Author(s):  
Ranggaski Yoan Vianus ◽  
Mohammad Ikhwan Yani ◽  
Fatma Sarie
Keyword(s):  
Mechanical Properties ◽  
Clay Soil ◽  
Physical And Mechanical Properties ◽  
Central Kalimantan ◽  
One Dimensional ◽  
Consolidation Test ◽  
A Value ◽  
Brick Powder ◽  
Consolidation Coefficient ◽  
Mixed Material

The waste from the wood and brick industry in Central Kalimantan is largely unused. The research objective aims to analyze the physical and mechanical properties of clay soil in the Tumbang Rungan area of ​​Palangka Raya City, Central Kalimantan and the effect of adding sawdust ash and brick powder based on the consolidation test and the time of subsidence of the clay soil using the Terzaghi one-dimensional consolidation method with the addition of a mixture of 2 variations 2,5%, 5% and 7,5%. Tests conducted are to obtain the consolidation reduction value (Sc) and the consolidation coefficient value (Cv). The results of the study using a mixture of sawdust ash and brick powder obtained changes in the Sc and Cv values ​​of the original soil. The original soil has a value of Sc (e) = 0.291 cm and Cv (t50) = 0.01913205 cm²/s, Cv (t90) = 0.031062161 cm²/s and the addition of a mixture of 5% variation of material has decreased the value of Sc (e) = 0.203 cm and Cv (t50) = 0.00722173 cm²/s, Cv (t90) = 0.011679143 cm²/s. The effective mixture variation for adding mixed material to clay is a variation of 5%.

scholarly journals An Investigation of Time-Dependent Deformation Characteristics of Soft Dredger Fill

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Wanying Wang ◽  
Qingzi Luo ◽  
Bingxiang Yuan ◽  
Xiaoping Chen
Keyword(s):  
Soft Clay ◽  
Deformation Characteristics ◽  
Soft Clays ◽  
Creep Coefficient ◽  
Creep Characteristics ◽  
Deformation Features ◽  
Consolidation Coefficient ◽  
Geometric Confinement ◽  
Dredger Fill ◽  
Two Parameters

The creep characteristics of soft clays have been studied for decades. However, the lateral deformation of soils is not allowed during the commonly used one-dimensional consolidation tests, which cannot describe the real deformation features of soils in practice. On the other hand, the influence of drainage distance on the mechanical properties of soil is still controversial, classified as hypothesis A and hypothesis B. For a better understanding of deformation characteristics of soft clay, especially which in long-terms, a series of conventional oedometer tests as well as novel geometric confined consolidation tests was conducted on soft dredger fill. The results show that the secondary consolidation coefficient of the soil sample Cα would increase firstly, followed by a small decrease with the increase of consolidation pressure generally. Cα would decrease with the consolidation time and also be reduced by preloading. The strain at the completion of primary consolidation would increase with the drainage distance, but the Cα would be affected little. Both compression index Cc and Cα of soft clay would reduce after preconsolidation, in which two parameters show an approximate linear relationship. The creep coefficient of soft clay under the geometric confinement Cαε k is larger than that under the oedometer test Cαε. However, the trends of the relationship between the creep coefficient and loading are consistent regardless of the confinement conditions.

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