Delft screw injection pile tests: factual report

This report presents the execution and results of axial pile load tests on screw injection piles in the south of Delft in 2022. Two types of screw injection piles were tested: a screw injection pile with the steel casing removed (SI, Fundex pile) and a screw injection pile with the casing remaining in-situ (Sic, Tubexpile).The tests were carried out with the guidance of NPR 7201 (NPR 7201, 2017) and NEN 9997-1 (NEN, 2017), with each pile loaded under compression to a pile base displacement of 20%. During this process, strains were measured along the entire pile length, giving comprehensive insights into the pile base and shaft response.

This document provides a factual summary of the results for dissemination to the NPR 7201 advisory committee, with the primary aim of fully detailing of the test methodology and execution, along with the underlying dataset. Minimal interpretation of these results is presented in this report and has instead been published in the following publications:

• Duffy, K.J., Gavin K.G., Korff, M., de Lange, D.A. (2024) Base resistance of screw displacement piles in sand. Journal of Geotechnical and Geoenvironmental Engineering, 150(8), https://doi-org.tudelft.idm.oclc.org/10.1061/JGGEFK.GTENG

• Kevin Duffy (2025) Axial capacity of piles in sand: A field investigation using distributed fibre optic sensing. [Doctoral dissertation, Delft University of Technology]. (to be published)

The data from the tests is publicly available on the 4TU.ResearchData repository under doi: 10.4121/78720ecb-daf4-4676-b5f4-281e93e4388a (Static load tests on screw injection piles with distributed fibre optic sensors in Delft).