THREE-DIMENSIONAL SEEPAGE ANALYSIS OF A COAL REFUSE PILE RECLAMATION

2020 ◽  
Vol 9 (4) ◽  
pp. 44-66
Author(s):  
Iuri Lira Santos ◽  
Keyword(s):  
Mine Drainage ◽  
Characteristic Curve ◽  
Water Volume ◽  
Low Permeability ◽  
Initial Water Content ◽  
Initial Water ◽  
Seepage Analysis ◽  
Cover System ◽  
Coal Refuse ◽  
Refuse Pile

Abstract. A coal refuse pile located in Greenbrier County, West Virginia was studied to restrict generation of acid mine drainage through the use of a cap and cover system. This paper presents results of a finite element method seepage analysis on a proposed reclamation design. The proposed reclamation incorporates a cap and cover system with a 0.3-m thick surface vegetation cap layer over a 0.6-m thick low permeability layer. The low permeability layer is directly above the coal refuse. Unsaturated soil mechanics was utilized, adopting the Fredlund and Xing equation for soil-water characteristic curve (SWCC) estimation. SWCC fitting parameters were calculated using the Zapata and the Hernandez estimation techniques. Different precipitation events were used to evaluate seepage throughout the reclamation area and assess the effectiveness of the cap and cover system. A steep area (>4H:1V) and a flat area were considered. The water balance analysis showed a 50% to 88% reduction in water volume at the coal refuse layer and a reduction in the time for the refuse to return to initial water content due to the cap and cover system implementation. Moisture detainment was observed in the growth layer and is important for supporting vegetation persistence.

scholarly journals Influence of bentonite type and producing method on hydraulic conductivity of sand–bentonite mixture

2020 ◽  
Vol 205 ◽  
pp. 10005
Author(s):  
Tomonori Sakita ◽  
Hideo Komine ◽  
Atsuo Yamada ◽  
Hailong Wang ◽  
Shigeru Goto
Keyword(s):  
Hydraulic Conductivity ◽  
Water Content ◽  
Water Mass ◽  
Water Volume ◽  
Dry Density ◽  
Initial Water Content ◽  
Specimen Preparation ◽  
Initial Water ◽  
Compaction Energy ◽  
Low Level Radioactive Waste

Sand-bentonite mixtures with bentonite content of 10-30% had been planned to handle low-level radioactive waste in Japan, because of its low permeability. Hydraulic conductivity of sand–bentonite mixture depends on the bentonite type, bentonite content, initial water content, and other factors. Given this background, falling head permeability tests were conducted on sand–bentonite mixture by varying the compaction energy for specimen preparation, initial water content (10–20%), and bentonite content (15– 30%). For these tests, the hydraulic gradient of 25-500 was set. Consequently, the hydraulic conductivities were 10-8 – 10-13 m/s for all tested conditions. Correlation between the hydraulic conductivity and the effective montmorillonite dry density (montmorillonite mass divided by the sum of montmorillonite, air, water volume), which is often used to correlate the hydraulic conductivity of bentonite, was found. Correlation was also found between the hydraulic conductivity and a new index designated as the effective montmorillonite wet density (sum of montmorillonite and water mass / sum of montmorillonite, air, water volume). Effective montmorillonite wet density reveals differences in the specimen structural distribution through consideration of the initial water content.

scholarly journals Effect of initial gravimetric water content and cyclic wetting-drying on soil-water characteristic curves of disintegrated carbonaceous mudstone

2019 ◽  
Vol 1 (3) ◽  
pp. 230-240
Author(s):  
Ling Zeng ◽  
Fan Li ◽  
Jie Liu ◽  
Qianfeng Gao ◽  
Hanbing Bian
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Initial Water Content ◽  
Test Results ◽  
Initial Water ◽  
Soil Water Characteristic Curves ◽  
Water Holding ◽  
Gravimetric Water Content ◽  
Plate Apparatus

Abstract The soil-water characteristic curve (SWCC) is often used to estimate unsaturated soil properties (e.g. strength, permeability, volume change, solute and thermal diffusivity). The SWCC of soil samples is significantly affected by cyclic wetting-drying. To examine how water content and cyclic wetting-drying affect the SWCC of disintegrated carbonaceous mudstone (DCM), SWCC tests were implemented using a pressure-plate apparatus. In addition, SWCC models for DCM considering the initial gravimetric water content and cyclic wetting-drying were developed. The test results showed that the volumetric water content (θ) of the DCM first decreased rapidly and then became stable as matric suction (s) increased. The initial water content affected the SWCC by altering the pore structure of the DCM. For a given number of wetting-drying cycles, the higher the initial water content, the higher the stabilized θ. At a given s value, θ decreased as the number of wetting-drying cycles increased, which suggests that cyclic wetting-drying reduces the water-holding capacity of DCM. The Gardner model for DCM was constructed considering initial water content and cyclic wetting-drying, and was effective at describing and predicting the SWCC model for DCM.

Research on the Soil Water Characteristic Curve and Prediction of Compacted Bentonite

2012 ◽  
Vol 518-523 ◽  
pp. 2785-2791
Author(s):  
Fa Cheng Yi ◽  
Zhe Wang ◽  
Min Juan Zhou
Keyword(s):  
Soil Water ◽  
Characteristic Curve ◽  
Phase Method ◽  
Dry Density ◽  
Initial Water Content ◽  
Initial Water ◽  
Soil Water Characteristic Curve ◽  
Retention Characteristics ◽  
Stress States ◽  
The Impact

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.

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

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

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

Experimental investigations of the soil-water characteristics of a volcanic soil

2000 ◽  
Vol 37 (6) ◽  
pp. 1252-1264 ◽  
Author(s):  
Charles WW Ng ◽  
Y W Pang
Keyword(s):  
Stress State ◽  
Water Content ◽  
Soil Water ◽  
Characteristic Curve ◽  
Hysteresis Loops ◽  
Initial Water Content ◽  
Volcanic Soil ◽  
Initial Water ◽  
Pressure Plate ◽  
Water Characteristics

Rain-induced landslides are common around the world. To analyse transient seepage and to predict pore-water pressure distribution in unsaturated slopes subjected to rainfall infiltration, it is essential to study soil-water characteristics and water permeability functions. The soil-water characteristic curve (SWCC) is a relationship between suction and water content or degree of saturation. Conventionally, only the drying soil-water characteristic curve of soil specimens is determined in a pressure-plate extractor without the application of any external stress. In this paper, the influences of initial dry density and initial water content, history of drying and wetting, soil structure, and the stress state upon the desorption and adsorption soil-water characteristics of a completely decomposed volcanic soil in Hong Kong are examined and discussed. The experimental results presented are obtained by using a conventional volumetric pressure-plate extractor and a newly modified one-dimensional stress-controllable pressure-plate extractor with deformation measurements. The SWCC of a recompacted specimen is very different from that of a natural specimen with the same initial soil density and initial water content. The SWCC of the recompacted specimen is highly dependent on the history of drying and wetting. The rates of desorption and adsorption are substantially higher at the first drying and wetting cycle than at the second drying and wetting cycle. The size of the hysteresis loop of the recompacted specimen is considerably larger than that of the natural specimens. The SWCC of soil is stress-state dependent. For recompacted specimens subjected to different stress states, the higher the applied stresses, the lower the rate of desorption and the smaller the size of the hysteresis loops. However, for natural specimens, the size of the hysteresis loops seems to be independent of the stress state. Under a higher applied stress, natural specimens exhibit lower rates of desorption and adsorption.Key words: volcanic soil, SWCC, drying and wetting, stress-state dependent.

The Numerical Modeling of Spherical Explosion in the Foam

2016 ◽  
Vol 11 (1) ◽  
pp. 60-65 ◽  
Author(s):  
R.Kh. Bolotnova ◽  
E.F. Gainullina
Keyword(s):  
Shock Wave ◽  
Numerical Modeling ◽  
Initial Pressure ◽  
Water Volume ◽  
Symmetric Model ◽  
Two Phase ◽  
Experimental Conditions ◽  
Initial Water ◽  
Aqueous Foam ◽  
Spherical Explosion

The spherical explosion propagation process in aqueous foam with the initial water volume content α10=0.0083 corresponding to the experimental conditions is analyzed numerically. The solution method is based on the one-dimensional two-temperature spherically symmetric model for two-phase gas-liquid mixture. The numerical simulation is built by the shock capturing method and movable Lagrangian grids. The amplitude and the width of the initial pressure pulse are found from the amount of experimental explosive energy. The numerical modeling results are compared to the real experiment. It’s shown, that the foam compression in the shock wave leads to the significant decrease in velocity and in amplitude of the shock wave.

Influence of initial water content and strain rate on remolded yield stress in marine clay

2021 ◽  
pp. 1-8
Author(s):  
Xiaobing Li ◽  
Jianpeng Chen ◽  
Xiuqing Hu ◽  
Hongtao Fu ◽  
Jun Wang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Water Content ◽  
Yield Stress ◽  
Initial Water Content ◽  
Marine Clay ◽  
Initial Water

scholarly journals Application of the Calorimetric Methods to the Characteristics of Seeds from Olives

Proceedings ◽  
2020 ◽  
Vol 70 (1) ◽  
pp. 90
Author(s):  
Andrzej Bryś ◽  
Joanna Bryś ◽  
Marko Obranović ◽  
Dubravka Škevin ◽  
Szymon Głowacki ◽  
...  
Keyword(s):  
Olive Oil ◽  
Water Content ◽  
Cooling System ◽  
Waste Product ◽  
Normal Pressure ◽  
Ash Content ◽  
Initial Water Content ◽  
Scanning Calorimetry ◽  
Initial Water

The olive oil industry represents an important productive sector in the Mediterranean basin countries. Olive stone is an essential by-product generated in the olive oil extraction industries and it represents roughly 10% by weight of the olive fruit. The seeds of pickled olives are also a significant waste product. In the present study, we have investigated the possibility of the use of differential scanning calorimetry for the thermal characterization of seeds from green and black pickled olives from Croatia. The differential scanning calorimeter (DSC) with a normal pressure cell equipped with a cooling system was used to determine the thermal properties of seeds from olives. The following analyses were also performed: the determination of calorific values in a pressure bomb calorimeter, the determination of initial water content, the determination of changes of water content during drying at the temperatures of 30 °C, 50 °C and 80 °C, the determination of a percentage content of seeds mass to the mass of the whole olives, and the determination of ash content. Seeds from olives are characterized by very good parameters as a biomass. The analyzed olive seeds were characterized by low water content, low ash content, and a relatively high caloric value.

scholarly journals RESEARCH ON MODEL FITTING AND STRENGTH CHARACTERISTICS OF CRITICAL STATE FOR EXPANSIVE SOIL

2013 ◽  
Vol 19 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Zhiqing Li ◽  
Chuan Tang ◽  
Ruilin Hu ◽  
Yingxin Zhou
Keyword(s):  
Critical State ◽  
Model Fitting ◽  
Expansive Soil ◽  
Dry Density ◽  
Initial Water Content ◽  
Test Results ◽  
Stress Strain ◽  
Initial Water ◽  
Curve Model ◽  
Shearing Strength

According to Mengzi expansive soil, consolidated drained tests and undrained tests are carried on under saturated and remoulded conditions. The stress-strain characteristics of saturated soil are researched systematically under different confining pressure, initial dry density, initial water content, shearing rate and drainage condition. The inherent unity of diversity of shearing strength for the same samples measured by different experimental methods is indicated according to the normalization of critical state test results. And the failure lines in p ‘- q - ν space of remoulded saturated expansive soil under consolidated drained and undrained conditions are attained. The hyperbolic curve model can fit well the weak hardening stress-strain curves and the exponential curve model can fit the weak softening stress-strain curves. The test results can provide technical parameters and theoretical help for shearing strength variation of slope during rainfall and strength state of soil structure in normal water level.

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