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

Adam Krasiński
Adam Krasiński
, 
Andrzej Słabek
Andrzej Słabek
, 
Paweł Więcławski
Paweł Więcławski
, 
Mateusz Wiszniewski
Mateusz Wiszniewski
, 
Tomasz Kusio
Tomasz Kusio
 and 
Witold Tisler
Witold Tisler
   | Oct 20, 2023
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Published Online: Oct 20, 2023
Page range: 89 - 99
Received: Jan 26, 2023
Accepted: Feb 26, 2023
DOI: https://doi.org/10.2478/acee-2023-0036
Keywords
© 2023 Adam Krasiński et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Figure 1.

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

Figure 2.

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

Figure 3.

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

Figure 4.

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

Figure 5.

Scheme for determining representative values of cone resistances qcs and qcb
Scheme for determining representative values of cone resistances qcs and qcb

Figure 6.

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

Figure 7.

Scheme for determining representative values of DMT membrane resistances ps and pb
Scheme for determining representative values of DMT membrane resistances ps and pb

Figure 8.

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

Figure 9.

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

Figure 10.

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

Figure 11.

Comparison of MT/qcr trend lines for all three augers from all experimental field plots
Comparison of MT/qcr trend lines for all three augers from all experimental field plots

Figure 12.

Derived MT dependencies on qc;r for the tested SDP, DPDT and DPDT-S pile augers
Derived MT dependencies on qc;r for the tested SDP, DPDT and DPDT-S pile augers

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

Soil type Pile shaft ts;ult [kPa] Pile base qb;ult [kPa] Scope of use
Cohesionless saturated ts;ult=85⋅(qcsqref)0.18 {t_{s;ult}} = 85 \cdot {\left( {{{{q_{cs}}} \over {{q_{ref}}}}} \right)^{0.18}} qb;ult=1660⋅(qcbqref)0.27 {q_{b;ult}} = 1660 \cdot {\left( {{{{q_{cb}}} \over {{q_{ref}}}}} \right)^{0.27}} qcb = 5 ÷ 35 MPaqcs = 5 ÷ 35 MPaincl. organ. ≤ 2%
Cohesionless unsaturated qb;ult=2050⋅(qcbqref)0.30 {q_{b;ult}} = 2050 \cdot {\left( {{{{q_{cb}}} \over {{q_{ref}}}}} \right)^{0.30}} qcs = 5 ÷ 35 MPaqcb = 5 ÷ 35 MPaincl. organ. ≤ 2%
Cohesive saturated ts;ult=39⋅(qcsqref)0.44 {t_{s;ult}} = 39 \cdot {\left( {{{{q_{cs}}} \over {{q_{ref}}}}} \right)^{0.44}} qb;ult=330⋅(qcbqref)0.78 {q_{b;ult}} = 330 \cdot {\left( {{{{q_{cb}}} \over {{q_{ref}}}}} \right)^{0.78}} qcs = 1 ÷ 4 MPaqcb = 1 ÷ 4 MPaincl. organ. ≤ 2%
Cohesive unsaturated ts;ult=48⋅(qcsqref)0.39 {t_{s;ult}} = 48 \cdot {\left( {{{{q_{cs}}} \over {{q_{ref}}}}} \right)^{0.39}} No data (A formula for cohesive saturated can be used) qcs = 1 4 MPaqcb = 1 4 MPaincl. organ. ≤ 2%

List of formulas for calculating ultimate resistances ts;ult and qb;ult of DPDT and SDP piles based on DMT soundings

Soil type Pile shaft ts;ult [kPa] Pile base qb;ult [kPa] Scope of use
Cohesionless saturated ts;ult=11.75⋅(Δpspref)0.31 {t_{s;ult}} = 11.75 \cdot {\left( {{{\Delta {p_s}} \over {{p_{ref}}}}} \right)^{0.31}} qb;ult=525⋅(Δpbpref)0.26 {q_{b;ult}} = 525 \cdot {\left( {{{\Delta {p_b}} \over {{p_{ref}}}}} \right)^{0.26}} Δps = 400 ÷ 2500 kPaΔpb = 500 ÷ 3000 kPaincl. organ. ≤ 2%
Cohesionless unsaturated qb;ult=950⋅(Δpbpref)0.24 {q_{b;ult}} = 950 \cdot {\left( {{{\Delta {p_b}} \over {{p_{ref}}}}} \right)^{0.24}} Δps = 400 ÷ 2500 kPaΔpb = 600 ÷ 3000 kPaincl. Organ. ≤ 2%
Cohesive saturated ts;ult=22⋅(Δpspref)0.14 {t_{s;ult}} = 22 \cdot {\left( {{{\Delta {p_s}} \over {{p_{ref}}}}} \right)^{0.14}} qb;ult=110⋅(Δpbpref)0.37 {q_{b;ult}} = 110 \cdot {\left( {{{\Delta {p_b}} \over {{p_{ref}}}}} \right)^{0.37}} Δps = 100 ÷ 600 kPaΔpb = 100 ÷ 1000 kPaincl. organ. ≤ 2%
Cohesive unsaturated ts;ult=25⋅(Δpspref)0.17 {t_{s;ult}} = 25 \cdot {\left( {{{\Delta {p_s}} \over {{p_{ref}}}}} \right)^{0.17}} No data (A formula for cohesive saturated can be used) Δps = 100 ÷ 600 kPaΔpb = 100 ÷1000 kPaincl. organ. ≤ 2%
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