<abstract xmlns="http://www.w3.org/1999/xhtml">

<p>With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.</p>
</abstract>

With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the requirements of new constructions. While current European standards include design procedures for structural and geotechnical design, they lack provisions for massive deep foundations with regard to early-age thermal effects. This paper presents aspects of the phenomenon especially important for deep foundations and discusses normative requirements that influence their thermal behaviour. Further, the paper describes the methods and results of the research carried out in the United Kingdom on 1.50-m-thick diaphragm walls of a deep circular shaft. Shaft features are described, as well as the materials used. The measurements were carried out using vibrating wire strain gauges coupled with temperature readings. The results presented refer to one of the test panels concreted in January 2020. The temperature results are analysed together with the influence of work scheduling on the readings. Strain results that indicate contractive behaviour of the test panel are investigated together with the possible causes leading to such readings. Plans and directions for future research are discussed.

Early-Age Thermal-Shrinkage Cracking in Deep Foundations

Studia Geotechnica et Mechanica

This work is licensed under the Creative Commons Attribution 4.0 International License.

{"article-title":"Early-Age Thermal-Shrinkage Cracking in Deep Foundations"}

With the growing rate of urbanisation, deep foundations are playing an ever-larger role in the development of cities, reaching deeper than before to fulfil the...

Measurement level	Depth (m)
L1	24.6
L2	34.6
L3	39.6
L4	49.6
L5	64.6

Parameter	Value	Unit
Cement content (CEM type I, ASTM compliant)	150	kg/m³
Supplementary cementitious material content (GGBS)	310	kg/m³
Superplasticisers and retarders	4.9–5.3	l/m³
Density, ρ	2400	kg/m³
Specific heat, c_p	895	J/(kg·K)

Panel	Event	Date, time	Time elapsed from the start of concreting (days)
P24 (instrumented)	Excavation start	23/01/2020, 10:45	−6
	Excavation end	27/01/2020, 16:45	−2
	Concreting start	29/01/2020, 08:22	0
	Concreting end	29/01/2020, 15:45	0
S23 (counter-clockwise side)	Excavation start	28/02/2020, 08:30	30
	Excavation end	04/03/2020, 15:00	35
	Concreting start	06/03/2020, 07:43	37
	Concreting end	06/03/2020, 19:10	37

Early-Age Thermal-Shrinkage Cracking in Deep Foundations

Article Category: Special Issue Article

Publié en ligne: 16 déc. 2021

Pages: 510 - 520

Reçu: 31 août 2021

Accepté: 05 nov. 2021

DOI: https://doi.org/10.2478/sgem-2021-0033

Mots clés
deep foundations, diaphragm walls, hydration heat, early-age thermal cracking, tremie concrete

© 2021 Łukasz Grabowski et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Measurement levels.

Concrete properties.

Important timeline events for the instrumented panel P24.

Early-Age Thermal-Shrinkage Cracking in Deep Foundations

Article Category: Special Issue Article

Publié en ligne: 16 déc. 2021

Pages: 510 - 520

Reçu: 31 août 2021

Accepté: 05 nov. 2021

DOI: https://doi.org/10.2478/sgem-2021-0033

Mots clésdeep foundations, diaphragm walls, hydration heat, early-age thermal cracking, tremie concrete

© 2021 Łukasz Grabowski et al., published by Sciendo

This work is licensed under the Creative Commons Attribution 4.0 International License.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Measurement levels.

Concrete properties.

Important timeline events for the instrumented panel P24.

Mots clés
deep foundations, diaphragm walls, hydration heat, early-age thermal cracking, tremie concrete