Experimental study on earth pressure reduction of waste tyre bales used as a backfill for rigid retaining structures

Aleksander Duda; Tomasz Siwowski

doi:10.2478/sgem-2021-0023

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Experimental study on earth pressure reduction of waste tyre bales used as a backfill for rigid retaining structures

Studia Geotechnica et Mechanica

Volume 43 (2021): Issue 4 (December 2021)

By: Aleksander Duda and Tomasz Siwowski

Open Access

|Nov 2021

Figures & Tables

Typical tyre bale used in the current study.

Scheme of a tyre bale with the basic dimensions.

Table 1

Basic dimensions and weights of tyre bales.

Bale no.	Number of tyres	Length L	Width B	Hight H	Area A	Volume V	Weight G	Unit weight γAVG
Bale no.	Number of tyres	(m)			(m²)	(m³)	(kg)	(kg/m³)
P-1	135	2.070	1.310	0.747	2.712	2.026	1038	512.43
P-2	135	2.040	1.317	0.757	2.689	2.034	1022	502.50
P-3	135	2.050	1.310	0.740	2.686	1.987	1012	509.24
P-4	135	2.040	1.323	0.737	2.699	1.989	1034	519.83
P-5	135	2.070	1.317	0.750	2.726	2.045	1049	513.05
P-6	135	2.060	1.295	0.750	2.668	2.001	1032	515.80
Avg.	135	2.055	1.312	0.747	2.697	2.014	1031	512.14

Table 2

Basic material characteristics of the filling materials.

Filling material	Granulation	Weight density	Moisture	Friction angle	Cohesion	State
Filling material	(mm)	(kN/m³)	(%)	(°)	(kPa)	State
Medium sand	0.25–1.00	18.5 ± 0.5	12.6–12.8	35.2	0	Loose / medium concentrated
LECA aggregate	8–20	3.2	18.7–22.2	35.3	0	Loose
Rubber aggregate	4–20	4.2	9.8–11.0	20.5^*	10.5^*	Loose

* Own tests for high normal stresses

Tyre bale–filling material interface test set-up (without additional normal loading).

(a) View of the test stand, (b) close-up on LVDTs sensors.

Exemplary curves for P-2 specimen in stage IV of tyre–medium sand shear test: (a) load–time curve, (b) load–displacement curve.

Table 3

Shear and normal stresses along the tyre bale–medium sand interface.

Bale no.	Area A	Normal load V	Failure load H_f	Normal stress σ	Shear stress τ	Shear stress τ_cal	Error estimation
Bale no.	(m²)	(kN)	(kN)	(kPa)	(kPa)	(kPa)	(%)
P-1	2.686	22.2	14.01	8.27	5.22	5.47	4.58
P-1	2.686	28.4	18.24	10.57	6.79	6.78	0.18
38.4	23.00	14.30	8.56	8.90	3.74
44.0	25.71	16.38	9.57	10.08	5.05
P-2	2.712	22.2	13.86	8.19	5.11	5.42	5.73
P-2	2.712	28.4	18.61	10.47	6.86	6.72	2.10
38.4	23.00	14.16	8.48	8.82	3.82
44.0	28.03	16.22	10.34	9.99	3.45
P-3	2.726	22.2	16.45	8.14	6.03	5.40	11.80
P-3	2.726	28.4	17.80	10.42	6.53	6.69	2.40
38.4	24.70	14.09	9.06	8.78	3.25
44.0	28.41	16.14	10.42	9.94	4.81

Table 4

Shear and normal stresses along the tyre bale–LECA interface.

Bale no.	Area A	Normal load V	Failure load H_f	Normal stress σ	Shear stress τ	Shear stress τ_cal	Error estimation
Bale no.	(m²)	(kN)	(kN)	(kPa)	(kPa)	(kPa)	(%)
P-1	2.686	22.2	12.00	8.27	4.47	4.28	4.28
P-1	2.686	28.4	14.22	10.57	5.29	5.46	3.00
38.4	20.41	14.30	7.60	7.35	3.37
44.0	22.79	16.38	8.48	8.41	0.87
P-2	2.712	22.2	11.62	8.19	4.28	4.24	0.96
P-2	2.712	28.4	14.59	10.47	5.38	5.41	0.49
38.4	19.86	14.16	7.32	7.28	0.57
44.0	22.69	16.22	8.37	8.33	0.42
P-3	2.726	22.2	11.30	8.14	4.15	4.22	1.83
P-3	2.726	28.4	14.56	10.42	5.34	5.38	0.71
38.4	19.23	14.09	7.05	7.24	2.63
44.0	22.25	16.14	8.16	8.29	1.53

Table 5

Shear and normal stresses along the tyre bale–rubber aggregate interface.

Bale no.	Area A	Normal load V	Failure load H_f	Normal stress σ	Shear stress τ	Shear stress τ_cal	Error estimation
Bale no.	(m²)	(kN)	(kN)	(kPa)	(kPa)	(kPa)	(%)
P-1	2.686	22.2	12.88	8.27	4.80	4.68	2.57
P-1	2.686	28.4	16.15	10.57	6.01	5.84	2.96
38.4	21.32	14.30	7.94	7.72	2.83
44.0	24.51	16.38	9.13	8.77	4.04
P-2	2.712	22.2	12.18	8.19	4.49	4.64	3.11
P-2	2.712	28.4	15.46	10.47	5.70	5.79	1.52
38.4	20.64	14.16	7.61	7.65	0.51
44.0	23.62	16.22	8.71	8.69	0.21
P-3	2.726	22.2	12.34	8.14	4.53	4.61	1.89
P-3	2.726	28.4	15.88	10.42	5.83	5.76	1.10
38.4	20.51	14.09	7.52	7.61	1.17
44.0	22.20	16.14	8.14	8.65	5.85

Shear stress–displacement curves for P-2 specimen in subsequent normal load stages: (a) medium sand test, (b) LECA aggregate test, (c) rubber aggregate test.

Shear strength envelopes: (a) tyre–medium sand interface, (b) tyre–LECA interface, (c) tyre–rubber aggregate interface.

Table 6

Shear strength parameters of tyre–filling interface.

Filling material	Friction angle Δ	Cohesion c	Determination coefficient R²
Filling material	(°)	(kPa)	Determination coefficient R²
Medium sand	29.6	0.77	0.962
LECA aggregate	27.0	0.08	0.994
Rubber aggregate	26.8	0.50	0.983

Active earth pressure distribution on a rigid wall in three load cases.

Table 7

Earth pressure reduction factors λ_E for a typical bridge abutment (H = 8.0 m, b = 4.0 m) and standard vertical surface load (q = 25 kPa).

Backfill type	ρ_IL	ρ_TB	ρ_b	ϕ_b	E_S/E_TB	λ_E
Backfill type	kN/m³	kN/m³	kN/m³	°	kN/m	%
Case A
Medium sand	19.00	0.00	19.00	35.0	164.8	0.0
Tyre–sand	19.00	5.40	7.67	29.6	25.4	84.6
Tyre–LECA	5.25	5.40	5.38	27.0	77.1	53.2
Tyre–rubber	5.40	5.40	5.40	26.8	77.5	53.0
Case B
Medium sand	19.00	0.00	19.00	35.0	200.0	0.0
Tyre–sand	19.00	5.40	7.67	29.6	64.2	67.9
Tyre–LECA	5.25	5.40	5.38	27.0	117.5	41.2
Tyre–rubber	5.40	5.40	5.40	26.8	118.0	41.0
Case C
Medium sand	19.00	0.00	19.00	35.0	219.0	0.0
Tyre–sand	19.00	5.40	7.67	29.6	17.1	92.2
Tyre–LECA	5.25	5.40	5.38	27.0	76.8	64.9
Tyre–rubber	5.40	5.40	5.40	26.8	77.7	64.5

[i] The standard vertical surface load q = 25 kPa according to PN-EN 1997-1 [23] was applied in this assessment.

Table 8

Earth pressure reduction factor λ_E in dependence on the wall's geometry.

Earth pressure reduction factor λE		H (m)
Earth pressure reduction factor λE		4	5	6	7	8	9	10
b (m)	1	26.0	22.3	19.6	17.5	15.8	14.5	13.3
	2	56.2	47.1	40.8	36.1	32.4	29.5	27.0
	3	91.7	74.6	63.6	55.7	49.7	45.0	41.2
4	100.0	100.0	88.3	76.6	67.9	61.2	55.7
5	100.0	100.0	100.0	98.7	86.9	77.9	70.7
6	100.0	100.0	100.0	100.0	100.0	95.3	86.3

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DOI: https://doi.org/10.2478/sgem-2021-0023 | Journal eISSN: 2083-831X (formerly 0137-124X) | Journal ISSN: 0137-6365

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Language: English

Page range: 411 - 424

Submitted on: Mar 30, 2021

Accepted on: Aug 31, 2021

Published on: Nov 1, 2021

Published by: Wroclaw University of Science and Technology

In partnership with: Paradigm Publishing Services

Keywords:

Related subjects:

Physics,

Mechanics and fluid dynamics

© 2021 Aleksander Duda, Tomasz Siwowski, published by Wroclaw University of Science and Technology
This work is licensed under the Creative Commons Attribution 4.0 License.

Volume 43 (2021): Issue 4 (December 2021)

Experimental study on earth pressure reduction of waste tyre bales used as a backfill for rigid retaining structures

Figures & Tables

Figure 1

Figure 2

Table 1

Table 2

Figure 3

Figure 4

Figure 5

Table 3

Table 4

Table 5

Figure 6

Figure 7

Table 6

Figure 8

Table 7

Table 8

Figure 9

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