Hydraulic Characterization of a Self-Weight Compacted Coal

Antonio Mario Federico; Osvaldo Bottiglieri; Francesco Cafaro; Gaetano Elia

doi:10.2478/sgem-2019-0031

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Hydraulic Characterization of a Self-Weight Compacted Coal

Studia Geotechnica et Mechanica

Volume 42 (2020): Issue 1 (April 2020)

By: Antonio Mario Federico, Osvaldo Bottiglieri, Francesco Cafaro and Gaetano Elia

Open Access

|Mar 2020

Figures & Tables

Particle size distribution of two coal samples.

Block of Indonesian Coal subjected to swelling/shrinkage test.

PVC cylindrical cell for the preliminary evaluation of the water retention potential of the coal.

Dry unit weights of coal cylindrical samples and physical model

a) View of coal during drying at room temperature; b) phase of prototype filling

a) Location of the mini-tensiometers; b) continuous data logging system; c) details of the mini-tensiometers

Spillways detail and filtering sheets: a) first layer; b) second layer

First imbibition phase: experimental data and corresponding numerical results

Comparison between measured and predicted variation of suction with time at ch1

Predicted infiltration due to: (a) an extreme rainfall event through an initially wet stockpile; (b) an extreme rainfall event through an initially dry stockpile; (c) a constant rainfall through an initially wet stockpile; (d) a constant rainfall through an initially dry stockpile.

Physical-volumetric parameters of the coal cylindrical samples: a) at initial state; b) after imbibition

a)

Sample	w₀	γ₀ (kN/m³)	G_s^*	γ_d (kN/m³)	e₀	S_r	θ	drying procedure / time (day)
1	15.9%	8.4	1.2	7.2	0.63	30%	0.12	hygroscopic / -
3	9.7%	8.5	1.2	7.8	0.52	23%	0.08	free drying / 2
2	7.7%	8.5	1.2	7.9	0.49	19%	0.06	free drying / 4
4	0.0%	7.7	1.2	7.7	0.52	0%	0.00	oven drying at 105°C / 2

Matric suction values measured along the central vertical of the prototype model: a) at initial state; b) during the drying phase

a)

ch1	ch2	ch3
(kPa)	(kPa)	(kPa)
61.9	56.3	65.1

Hydraulic function parameters: a) at the first infiltration test; b) at the second infiltration test

a)
θ_r	θ₀	α	*a=1/*α	n′	k_s	l
		(kPa)⁻¹	(kPa)		(m/s)
0.0165	0.3014	1.670	0.598	1.703	8.0E-04	1

Compositional data of the coal

Determination	Standard/Method	Weight (%)	Note
Moisture in the Analysis Sample*	ISO 11722:1999	11.1	Air Dried Basis
Ash Content*	ISO 1171:2010 (E)	5.8	As Received Basis
Volatile Matter*	ISO 562:2010 (E)	37.4	As Received Basis
Fixed Carbon*	By calculation	42.3	As Received Basis
Carbon**	ASTM D 5373-08	65.7	Air Dried Basis
Hydrogen**	ASTM D 5373-08	4.4	Air Dried Basis
Nitrogen**	ASTM D 5373-08	1.3	Air Dried Basis
Sulphur**	ASTM D 4239-10	0.8	Air Dried Basis
Oxygen**	By calculation	10.7	Air Dried Basis

Hydraulic properties of the Indonesian coal in comparison to other granular materials

*Material*	a (kPa)	*k_s (m/s)*
Indonesian Coal – virgin state(present study)	0.60	8.0E-4
Indonesian Coal – after collapse(present study)	1.23	1.0E-5
Silty Clayey Sand(Cafaro et al. 2008)	0.63	1.58E-6
Pervious Concrete – different mixtures(Marzulli et al. 2018)	3.071.56	2E-45E-3
Sand(Lu and Likos 2004)	10	3E-4

WRC parameters for the drying phase following the first imbibition stage

θ_r	θ₀	α	*a=1/*α	n′
		(kPa)⁻¹	(kPa)
0.0165	0.3014	0.812	1.231	1.703

Physical-volumetric state of the coal in the prototype model during the drying phases

*After 7 days of drying at room temperature*
w	W (N)	W_d(N)	H (m)	V (m³)	G_s^*
17.70%	2096	1781	0.895	0.2238	1.20
γ (kN/m³)	γ_d (kN/m³)	e	n	S_r	θ
9.37	7.96	0.48	0.32	44.39%	0.144
*After 14 days of drying at room temperature*
w	W (N)	W_d (N)	H (m)	V (m³)	G_s^*
16.73%	2082	1781	0.895	0.2238	1.20
γ (kN/m³)	γ_d (kN/m³)	e	n	S_r	θ
9.31	7.96	0.48	0.32	41.97%	0.136

Physical-volumetric parameters of the coal in the prototype model: a) at initial state; b) after volumetric collapse

a)

w₀	W₀ (N)	W_d(N)	H (m)	V (m³)	G_s^*
11.21%	1984	1784	1.002	0.2505	1.20
γ (kN/m³)	γ_d (kN/m³)	e	n	S_r	θ
7.92	7.12	0.65	0.39	20.61%	0.081

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DOI: https://doi.org/10.2478/sgem-2019-0031 | Journal eISSN: 2083-831X | Journal ISSN: 0137-6365

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Language: English

Page range: 48 - 60

Submitted on: May 2, 2019

Accepted on: Sep 17, 2019

Published on: Mar 19, 2020

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

Environmental engineering,

seepage,

coal stocks,

unsaturated soils,

porous-media characterisation,

mining and environmental issues

Related subjects:

Physics,

Mechanics and fluid dynamics

© 2020 Antonio Mario Federico, Osvaldo Bottiglieri, Francesco Cafaro, Gaetano Elia, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 42 (2020): Issue 1 (April 2020)

Hydraulic Characterization of a Self-Weight Compacted Coal

Figures & Tables

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Physical-volumetric parameters of the coal cylindrical samples: a) at initial state; b) after imbibition

Matric suction values measured along the central vertical of the prototype model: a) at initial state; b) during the drying phase

Hydraulic function parameters: a) at the first infiltration test; b) at the second infiltration test

Compositional data of the coal

Hydraulic properties of the Indonesian coal in comparison to other granular materials

WRC parameters for the drying phase following the first imbibition stage

Physical-volumetric state of the coal in the prototype model during the drying phases

Physical-volumetric parameters of the coal in the prototype model: a) at initial state; b) after volumetric collapse

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