Results of the “DPDT-Auger” Research Project on Screw Displacement Piles

Adam Krasiński; Andrzej Słabek; Paweł Więcławski; Mateusz Wiszniewski; Tomasz Kusio; Witold Tisler

doi:10.2478/acee-2023-0036

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Results of the “DPDT-Auger” Research Project on Screw Displacement Piles

Architecture, Civil Engineering, Environment

Volume 16 (2023): Issue 3 (September 2023)

By: Adam Krasiński, Andrzej Słabek, Paweł Więcławski, Mateusz Wiszniewski, Tomasz Kusio and Witold Tisler

Open Access

|Oct 2023

Figures & Tables

Construction of the prototype DPDT drill auger according to Patent No. PL 235442 B1, [1]

Displacement pile augers tested in the research project: a) DPDT auger, b) DPDT-S auger (shortened length version), c) SDP auger, [6]

A graphical comparison of the screwing parameters of DPDT, DPDT-S and SDP augers (Test plot No. 2)

Comparative results of pile load tests from experimental plot No. 2, [6]

Scheme for determining representative values of cone resistances *q_cs* and *q_cb*

Correlations between ultimate unit resistances of DPDT and SDP piles and representative CPT(U) cone resistances for cohesionless and cohesive soils

Scheme for determining representative values of DMT membrane resistances *p_s* and *p_b*

Correlations of ultimate unit resistances around DPDT and SDP piles and representative DMT membrane resistances

Table 1.

List of formulas for calculating ultimate resistances t_s;ult and q_b;u_lt of the soil around DPDT and SDP piles, based on CPT(U) soundings

Soil type	Pile shaft t_s;ult [kPa]	Pile base q_b;ult [kPa]	Scope of use
Cohesionless saturated	$t_{s; ult} = 85 \cdot {(\frac{q_{cs}}{q_{ref}})}^{0.18}$	$q_{b; ult} = 1660 \cdot {(\frac{q_{cb}}{q_{ref}})}^{0.27}$	q_cb = 5 ÷ 35 MPa qcs = 5 ÷ 35 MPa incl. organ. ≤ 2%
Cohesionless unsaturated	$t_{s; ult} = 85 \cdot {(\frac{q_{cs}}{q_{ref}})}^{0.18}$	$q_{b; ult} = 2050 \cdot {(\frac{q_{cb}}{q_{ref}})}^{0.30}$	q_cs = 5 ÷ 35 MPa q_cb = 5 ÷ 35 MPa incl. organ. ≤ 2%
Cohesive saturated	$t_{s; ult} = 39 \cdot {(\frac{q_{cs}}{q_{ref}})}^{0.44}$	$q_{b; ult} = 330 \cdot {(\frac{q_{cb}}{q_{ref}})}^{0.78}$	q_cs = 1 ÷ 4 MPa q_cb = 1 ÷ 4 MPa incl. organ. ≤ 2%
Cohesive unsaturated	$t_{s; ult} = 48 \cdot {(\frac{q_{cs}}{q_{ref}})}^{0.39}$	No data (A formula for cohesive saturated can be used)	q_cs = 1 4 MPa q_cb = 1 4 MPa incl. organ. ≤ 2%

[i] Comments:

[ii] 1) values of q_cs;i and q_cb should be given in MPa

[iii] 2) reference stress should be taken as q_ref = 1 MPa

Table 2.

List of formulas for calculating ultimate resistances t_s;ult and q_b;u_lt of DPDT and SDP piles based on DMT soundings

Soil type	Pile shaft t_s;ult [kPa]	Pile base q_b;ult [kPa]	Scope of use
Cohesionless saturated	$t_{s; ult} = 11.75 \cdot {(\frac{Δ p_{s}}{p_{ref}})}^{0.31}$	$q_{b; ult} = 525 \cdot {(\frac{Δ p_{b}}{p_{ref}})}^{0.26}$	Δp_s = 400 ÷ 2500 kPa Δp_b = 500 ÷ 3000 kPa incl. organ. ≤ 2%
Cohesionless unsaturated		$q_{b; ult} = 950 \cdot {(\frac{Δ p_{b}}{p_{ref}})}^{0.24}$	Δp_s = 400 ÷ 2500 kPa Δp_b = 600 ÷ 3000 kPa incl. Organ. ≤ 2%
Cohesive saturated	$t_{s; ult} = 22 \cdot {(\frac{Δ p_{s}}{p_{ref}})}^{0.14}$	$q_{b; ult} = 110 \cdot {(\frac{Δ p_{b}}{p_{ref}})}^{0.37}$	Δp_s = 100 ÷ 600 kPa Δp_b = 100 ÷ 1000 kPa incl. organ. ≤ 2%
Cohesive unsaturated	$t_{s; ult} = 25 \cdot {(\frac{Δ p_{s}}{p_{ref}})}^{0.17}$	No data (A formula for cohesive saturated can be used)	Δp_s = 100 ÷ 600 kPa Δp_b = 100 ÷1000 kPa incl. organ. ≤ 2%

[i] Comments:

[ii] 1) values of Δp_s and Δp_b should be given in kPa

[iii] 2) reference stress should be taken as p_ref = 1 kPa

An example of calculating and determining the *Q-s* characteristic of a DPDT pile

Scheme for determining representative cone resistance values *q_cr* from CPT probing graph and for individual pile auger types

Comparison of *M_T/q_cr* trend lines for all three augers from all experimental field plots

Derived *M_T* dependencies on *q_c;r* for the tested SDP, DPDT and DPDT-S pile augers

References

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DOI: https://doi.org/10.2478/acee-2023-0036 | Journal eISSN: 2720-6947 (formerly 1899-0142) | Journal ISSN: 1899-0142

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Language: English

Page range: 89 - 99

Submitted on: Jan 26, 2023

Accepted on: Feb 26, 2023

Published on: Oct 20, 2023

Published by: Silesian University of Technology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

Screw displacement pile,

Pile auger,

Pile load capacity,

Soil resistance during pile formation,

Piles calculation

Related subjects:

Architecture and design,

Architecture,

Architects, buildings

© 2023 Adam Krasiński, Andrzej Słabek, Paweł Więcławski, Mateusz Wiszniewski, Tomasz Kusio, Witold Tisler, published by Silesian University of Technology
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 License.

Volume 16 (2023): Issue 3 (September 2023)

Results of the “DPDT-Auger” Research Project on Screw Displacement Piles

Figures & Tables

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Table 1.

Table 2.

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