Dynamic Replacement: The Influence of Pounder Diameter and Ground Conditions on Shape and Diameter of the Columns

Author(s)	Ground conditions	D_c/D_p [-]	M_p/H_d [Mg] / [m]	Shapes of columns
Kumar [4]	0–0.6 m: fill 0.6–1.5 m: medium stiff sandy silt 1.5–3.0 m: medium stiff silty clay 3.0–12.5 m: loose fine and medium sand	1.0 – 1.25	19 / 21	-
Varaksin and Hamidi [19]	0–1.5 m: disturbed clay from 1.5 m: very stiff clay	1.41	38.5 / 5	-
Lo et al. [25]	0–5.8 m: peaty clay from 5.8 m: old alluvium	-	15 / 15	Inverted truncated cone
Chua et al. [5]	0–2 m: loose sand (fill) 2–3 m: soft clay 3–10 m: medium dense to dense sand	-	24–26/10–20	Inverted truncated cone
Sękowski et al. [27]	0–1.5 m: working platform (semi-dense medium sand) 1.5–3.2 m: soft organic mud 3.2–5.0 m: semi-dense medium sand	1.7–2.4	11 / 10	Inverted truncated cone
Gunaratne et al. [26]	0–1.2 m: working platform 1.2–3.0 m: organic soil from 3.0 m: silty sand	2.46	4 / 12	Cylindrical
Kwiecień and Sękowski [23]	various ground conditions (11 columns)	1.5–2.7	10.5–12.0 / 15–25	Cylindrical, Inverted truncated cone
Kwiecień [22], Kwiecień and Sękowski [24]	various ground conditions (34 columns)	1.23–4.1	9–12 / 15–25	Inverted truncated cone, Barrel-shaped
Kwiecień [15]	various ground conditions (65 columns)	-	9–24 /15–25	End bearing columns: cylindrical, truncated cone, barrel, asymmetrical barrel Floating columns: cylindrical, barrel, inverted truncated cone

1 D_c – diameter of the column, Dp – diameter of the pounder, Hp – height of the pounder, H_s – thickness of the weak soil, Mp mass of the pounder, Hd – height of the pounder drop

Table 2.

Geographic location and ground conditions at the sites

Site No.	Location (Poland)	Ground conditions
1.	S7 motorway, km 711+050	Organic clayey mud, I_C = 0.56 - 0.60 (0 – 1.70 m – C1; 0 – 2.00 m – C2) Gravel, I_D = 50% (down to 4.00 m)
2.	A1 highway, km 516+715	Working platform (0 – 0.60 m) Organic Mud, I_c = 0.56 – 0.60 (0.60 - 1.50 m) Silty Clay + Or, I_c = 0.62 (1.50 – 2.00 m – C3; 1.50 – 2.10 m – C4) Sandy Silt + Or, I_c = 0.42 (2.00 – 2.50 m – C3; 2.10 – 2.60 m – C4) Fine Sand, I_D = 65% (down to 5.00 m)
3.	A1 highway, km 512+520	Working platform (0 – 0.50 m) Made ground (0.50 – 1.20 m) Sandy Silt, I_C = 0.58 (1.20 – 2.80 m – C5; 1.20 - 3.00 m – C6; 1.20 - 3.30 m – C7) Coarse Sand, I_D = 65% (down to 5.00 m).
4.	A4 highway, km 467+260	Working platform (0 - 0.50 m) Silty Clay, I_C = 0.50 (0.50 – 1.00 m – C10) Sandy Silt, I_c = 0.50 (0.50 – 3.20 m – C8; 0.50 – 3.10 m – C9; 1.00 – 3.50 m – C10) Medium Sand, I_D = 55 – 70%, (down to 5.0 m)
5.	A4 highway, km 461+050	Working platform (0 - 0.50 m) Silty Clay + Or, I_C = 0.65 – 0.76 (0.50 – 2.30 m – C11; 0.50 – 2.10 m – C12) Sandy Silt, I_C = 0.52 – 0.56 (2.30 – 3.20 m – C11; 2.10 – 3.20 m – C12) Medium Sand, I_D = 70 – 90% (down to 5.00 m)
6.	A4 highway, km 462+600	Working platform (0 – 0.50 m) Silty Clay + Or, I_C = 0.50 (0.50 – 1.00 m) Peat (1.00 – 1.20 m) Organic Mud, I_C = 0.44 (1.20 – 3.40 m) Gravely Sand, I_D = 50% (down to 5.00 m)
7.	A4 highway, km 464+720	Working platform (0 - 0.20 m Silty Clay + Or, I_C = 0.76 (0.20 – 1.40 m) Organic Mud, I_C = 0.37 (1.40 – 3.40 m – C15; 1.40 – 3.50 m – C16) Medium Sand, I_D = 80% (down to 5.00 m)
8.	A4 highway, km 461 + 150	Working platform (0 – 0.50 m) Clay, Silty Clay, I_C = 0.70 – 0.72 (0.50 – 2.40 m – C17; 0.50 – 2.50 m – C18) Medium Sand, I_D = 0.30 (2.40 – 3.2 m – C17) or Silty Clay, IC = 0.6 (2.5 – 3.2 m – C18) Silty Clay, I_C = 0.60 (3.20 – 3.80 m – C17 & C18) Medium Sand, I_D = 55% (down to 6.00 m)

1 I_C – consistency index: I_C = (w_L – w_n)/(w_L – W_p), where: w_n – natural water content, w_L – liquid limit, W_p – plastic limit; depending on I_C the soil is: very stiff (I_C > 1), stiff (I_c = 0.75 – 1), firm (I_C = 0.5 - 0.75), soft (I_C = 0.25 – 0.5) or very soft I_C < 0.25) [28]; I_D – density index: I_D = (e_max - e)/(e_max - e_mi_n), where e_max – void ratio in the loosest state, e_mi_n – void ratio in the densest state, e – natural voids ratio of the deposit, Or – with organic content; depending on I_D the soil is: very loose (I_D = 0 – 15%), loose (I_D = 15 – 35%), medium dense (I_D = 35 – 65%), dense (I_D = 65 – 85%) or very dense (I_D = 85 – 100%) [28]

Table 3.

List of investigated columns, their diameters, lengths and technological information

Site No.	Column	Diameters of the column (D_cmin – D_cmax)	Length of the column H_c	Shape, diameter (D_p), height (H_p) and mass (M_p) of the pounder	Number x height of the pounder drops/type, grading (d) and volume (V) of the aggregate
1.	C1 C2	2.00–2.24 2.00–2.28	2.00 m 2.00 m	Barrel-shaped, D_p = 1.05 m, H_p = 2.00 m, Mp = 11.50 Mg	1 x 5 m, 10 x 15 m, 1 x 5 m crushed sandstone d = 0 – 400 mm, V = 8.0 m³
2.	C3 C4	1.60–2.50 1.70–2.50	2.50 m 2.60 m	Barrel-shaped, D_p = 1.00 m, H_p = 1.80 m, Mp = 9 Mg	1 x 5 m, 17 x 15 m, 1 x 5 m, blast furnace slag d = 10 – 120 mm, V = 9.5 m³
3.	C5 C6 C7	1.70–2.47 1.80–2.39 1.80–2.40	2.90 m 3.10 m 3.40 m		1 x 5m, 22 x 15 m, 1 x 5 m blast furnace slag d = 10 – 120 mm, V = 11,5–13.0 m³
4.	C8 C9 C10	1.40–2.39 1.90–2.27 1.50–2.26	3.20 m 3.10 m 3.50 m		1 x 5 m, 22 x 15 m, 1 x 5 m blast furnace slag d = 0 – 350 mm, V = 12.0 m³
5.	C11 C12	1.80–2.78 1.50–2.58	3.20 m 3.20 m		1 x 5 m, 22 x 15 m, 1 x 5 m blast furnace slag d = 0 – 350 mm, V = 15.0 m³
6.	C13 C14	1.73 - 2.80 2.00 - 2.69	3.40 m 3.40 m		1 x 5 m, 23 x 15 m, 1 x 5 m blast furnace slag d = 0 – 350 mm, V = 18.0 m³
7.	C15 C16	2.30 - 2.60 2.20 - 2.60	3.40 m 3.50 m		1 x 5 m, 22 x 15 m, 1 x 5 m, blast furnace slag d = 0 – 350 mm, V = 17.0 m³
8.	C17 C18	1.50 - 2.74 1.50 - 2.68	3.80 m 3.80 m		1 x 5 m, 22 x 15 m, 1 x 5 m blast furnace slag d = 0 – 350 mm, V = 18.0 m³

Table 4.

Details on the shapes of the columns, ratio of the thickness of the improved layer and the height of the pounder, the maximum and mean consistency indexes of the soil layers along at the column length and relations to the diameters of the column and of the pounder

Site No.	Column	Diameter variation / Shape	H_s/H_p [-]	I_c(min) [-]	I_c(m) [-]	D_cmax/D_p [-]	D_cmin/D_p [-]	D_cm/D_p [-]	D_cmax/D_cmin [-]
1.	C1	constant / cylindrical	0.85	0.56	0.56	2.13	1.90	2.04	1.12
	C2	constant / cylindrical	1.00	0.60	0.60	2.17	1.90	2.07	1.14
2.	C3	increases with depth / truncated cone	1.39	0.42	0.54	2.50	1.60	2.08	1.56
	C4	increases with depth / truncated cone	1.44	0.42	0.56	2.50	1.70	2.19	1.47
3.	C5	the largest diameter at the bottom / asymmetrical barrel	1.56	0.58	0.58	2.47	1.70	2.20	1.45
	C6		1.67	0.58	0.58	2.39	1.80	2.15	1.33
	C7		1.83	0.58	0.58	2.40	1.80	2.17	1.33
4.	C8	the largest diameter at the mid-length / barrel-shaped	1.77	0.50	0.50	2.39	1.40	2.09	1.71
	C9		1.72	0.50	0.50	2.27	1.90	2.10	1.19
	C10		1.94	0.50	0.50	2.26	1.50	1.99	1.51
5.	C11	the largest diameter at the bottom / asymmetrical barrel	1.78	0.56	0.62	2.78	1.80	2.36	1.54
	C12	the largest diameter at the bottom / asymmetrical barrel	1.78	0.52	0.66	2.58	1.50	2.27	1.72
6.	C13	the largest diameter at barrelthe mid-length /	1.89	0.44	0.45	2.80	1.73	2.45	1.62
	C14	the largest diameter at barrelthe mid-length /	1.89	0.44	0.45	2.69	2.00	2.45	1.35
7.	C15	the largest diameter at the mid-length /	1.89	0.37	0.52	2.60	2.30	2.44	1.13
	C16	the largest diameter at the mid-length /	1.94	0.37	0.51	2.60	2.20	2.38	1.18
8.	C17	the largest diameter at the bottom / asymmetrical barrel	2.11	0.40	0.68	2.74	1.50	2.30	1.83
	C18	the largest diameter at the bottom / asymmetrical barrel	2.11	0.30	0.54	2.68	1.50	2.37	1.79

Shapes of columns at site No. 1.: C1 (left), C2 (right)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 1, columns C1 and C2

Shapes of columns at site No. 2.: C3 (top), C4 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 2, columns C3 and C4

Shapes of columns at site No. 3.: C5 (top), C6 (middle), C7 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 3, columns C5, C6 and C7

Shapes of columns at site No. 4: C8 (top), C9 (middle), C10 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 4, columns C8, C9 and C10

Shapes of columns at site No. 5: C11 (top), C12 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 5, columns C11 and C12

Shapes of columns at site No. 6: C13 (top), C14 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 6, columns C13 and C14

Shapes of columns at site No. 7: C15 (top), C16 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 7, columns C15 and C16

Shapes of columns at site No. 8: C17 (top), C18 (bottom)

Dependence between the ratio of the column and pounder diameters (D_c/D_p) and the relative depth (H/H_c) – Site No. 8, columns C17 and C18

Propagation of the aggregate during driving a floating DR column [15]

Relation between the consistency of the weakest soil and the relative maximal diameters of the columns

Relation between the H_s/H_p ratios and the mean relative diameters of columns D_cm/D_p

Relation between the maximum grain size of the aggregate used as the replacement material and the mean relative diameters of the columns D_cm/D_p

References

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Articles in this issue

DOI: https://doi.org/10.2478/acee-2023-0005 | Journal eISSN: 2720-6947 (formerly 1899-0142) | Journal ISSN: 1899-0142

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Language: English

Page range: 71 - 84

Submitted on: Mar 10, 2022

Accepted on: Dec 13, 2022

Published on: Apr 24, 2023

Published by: Silesian University of Technology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

Dynamic replacement columns,

Geotechnical engineering,

Ground improvement,

Column shape,

Weak soils

Related subjects:

Architecture and design,

Architecture,

Architects, buildings

© 2023 Sławomir Kwiecień, Magdalena Kowalska, published by Silesian University of Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 16 (2023): Issue 1 (March 2023)

Dynamic Replacement: The Influence of Pounder Diameter and Ground Conditions on Shape and Diameter of the Columns

Figures & Tables

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Table 4.

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Figure 13.

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Figure 15.

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Figure 20.

Figure 21.

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