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Identification of residual force in static load tests on instrumented screw displacement piles

Adam Krasiński

Adam Krasiński

Faculty of Civil and Environmental Engineering, Gdansk University of TechnologyGdansk, Poland
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Krasiński, Adam
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Mateusz Wiszniewski

Mateusz Wiszniewski

Faculty of Civil and Environmental Engineering, Gdansk University of TechnologyGdansk, Poland
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Wiszniewski, Mateusz
  
Dec 13, 2021
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Article Category: Original Study
Published Online: Dec 13, 2021
Page range: 438 - 451
Received: May 29, 2021
Accepted: Sep 07, 2021
DOI: https://doi.org/10.2478/sgem-2021-0025
Keywords
© 2021 Adam Krasiński et al., published by Sciendo
This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

The stress–strain relation measured in the first section of the pile (pile no. 6293): a) general for loading and unloading, b) only for loading, described by a function.
The stress–strain relation measured in the first section of the pile (pile no. 6293): a) general for loading and unloading, b) only for loading, described by a function.

Figure 2

Axial load distribution along the pile shaft (pile no. 6293)
Axial load distribution along the pile shaft (pile no. 6293)

Figure 3

The mechanism of residual force generation in a screw displacement pile: a) phase of soil spreading by the auger, b) phase after the pile is completed and the concrete has hardened.
The mechanism of residual force generation in a screw displacement pile: a) phase of soil spreading by the auger, b) phase after the pile is completed and the concrete has hardened.

Figure 4

An example of test result with the presence of initial compressive (residual) force in the pile shaft found due to shaft elongation after unloading (pile no. 6293).
An example of test result with the presence of initial compressive (residual) force in the pile shaft found due to shaft elongation after unloading (pile no. 6293).

Figure 5

The stress–strain relation in the first measuring section of the pile shaft, determined for the unloading phase and described by function (for the same example as in Fig. 1, pile no. 6293).
The stress–strain relation in the first measuring section of the pile shaft, determined for the unloading phase and described by function (for the same example as in Fig. 1, pile no. 6293).

Figure 6

Pile no. 6293, CPTu sounding and the basic result of the load test
Pile no. 6293, CPTu sounding and the basic result of the load test

Figure 7

Pile no. 6293, interpretation of qs and qb unit soil resistances around the pile, based on the data from Figs 2 and 6, without taking into account the influence of the residual force.
Pile no. 6293, interpretation of qs and qb unit soil resistances around the pile, based on the data from Figs 2 and 6, without taking into account the influence of the residual force.

Figure 8

Pile no. 6293: (a) determination of the residual force in the pile shaft and (b) its inclusion in the distribution of the axial force along the pile in successive load steps.
Pile no. 6293: (a) determination of the residual force in the pile shaft and (b) its inclusion in the distribution of the axial force along the pile in successive load steps.

Figure 9

Pile no. 6293, interpretation of qs and qb unit soil resistances around the pile after taking the residual force into account.
Pile no. 6293, interpretation of qs and qb unit soil resistances around the pile after taking the residual force into account.

Figure 10

Pile no. 6293, comparison of qs and qb unit soil resistances around the pile for the cases: a) without taking into account the residual force and b) taking into account the residual force
Pile no. 6293, comparison of qs and qb unit soil resistances around the pile for the cases: a) without taking into account the residual force and b) taking into account the residual force

Figure 11

Pile no. 9, basic result of the load test.
Pile no. 9, basic result of the load test.

Figure 12

Pile no. 9, graphs of the pile shaft deformation in individual measuring sections and in subsequent stages of pile loading and unloading.
Pile no. 9, graphs of the pile shaft deformation in individual measuring sections and in subsequent stages of pile loading and unloading.

Figure 13

Stress–strain relation in the pile shaft determined in the first measuring section: a) general for load and unload; b) for load 1, described by a function and c) for unload 1, described by a function.
Stress–strain relation in the pile shaft determined in the first measuring section: a) general for load and unload; b) for load 1, described by a function and c) for unload 1, described by a function.

Figure 14

Pile no. 9. Axial load distribution along the pile shaft without taking into account the influence of the residual force.
Pile no. 9. Axial load distribution along the pile shaft without taking into account the influence of the residual force.

Figure 15

Pile no. 9, interpretation of qs and qb unit soil resistances around the pile without taking into account the influence of the residual force.
Pile no. 9, interpretation of qs and qb unit soil resistances around the pile without taking into account the influence of the residual force.

Figure 16

Pile no. 9, determination of the residual force in the pile shaft (a) after first unloading (b) after second unloading and (c) its inclusion in the distribution of the axial force along the pile in successive load steps.
Pile no. 9, determination of the residual force in the pile shaft (a) after first unloading (b) after second unloading and (c) its inclusion in the distribution of the axial force along the pile in successive load steps.

Figure 17

Pile no. 9, interpretation of qs and qb unit soil resistances around the pile after taking the residual force into account.
Pile no. 9, interpretation of qs and qb unit soil resistances around the pile after taking the residual force into account.

Figure 18

Pile no. 9, comparison of qs and qb unit soil resistances around the pile for the cases: a) without taking into account the residual force and b) taking into account the residual force.
Pile no. 9, comparison of qs and qb unit soil resistances around the pile for the cases: a) without taking into account the residual force and b) taking into account the residual force.
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English
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Geosciences, Geosciences, other, Materials Sciences, Composites, Porous Materials, Physics, Mechanics and Fluid Dynamics
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