Abstract
Deployment of renewable energy foundations, be it piles or gravity based structures, may come into contact with chalk in southern UK waters and in other parts of European offshore and nearshore deployment. To aid more appropriate design it is useful to understand the interface shear strength between the foundation and the underlying rock where this is exposed at surface or where the foundation penetrates. In this paper, the interface shear strength between chalk and unbonded concrete is investigated for constant normal stress conditions over a range of normal stresses using tilt table and specialised interface shear testing apparatus. The results show that the interface strength of chalk is significantly influenced by the normal stress used during testing where at lower stresses the interface strength exceeds the basic friction angle determined for a chalk-chalk interface and degradation of the interface strength below the basic friction angle occurs when normal stresses exceed 73% of the tensile strength of the chalk material. This degradation is more severe at small displacements than previously observed for chalk-steel interfaces. At low normal stresses and displacements, the shear strength of the chalkconcrete interface can be represented by an alpha type approach related to the chalk unconfined compressive strength as previously developed for higher strength rocks.
| Original language | English |
|---|---|
| Title of host publication | Engineering in Chalk |
| Subtitle of host publication | Proceedings of the Chalk 2018 Conference |
| Editors | J. A. Lawrence, M. Preene, U. L. Lawrence, R. Buckley |
| Place of Publication | London |
| Publisher | ICE Publishing |
| Pages | 521-527 |
| Number of pages | 7 |
| ISBN (Electronic) | 9780727764089 |
| ISBN (Print) | 9780727764072 |
| DOIs | |
| Publication status | Published - 2018 |
| Event | Engineering in Chalk 2018 International Conference - Imperial College London, London, United Kingdom Duration: 17 Sep 2018 → 19 Sep 2018 https://www.chalk2018.org/about/committees |
Conference
| Conference | Engineering in Chalk 2018 International Conference |
|---|---|
| Country | United Kingdom |
| City | London |
| Period | 17/09/18 → 19/09/18 |
| Internet address |
Fingerprint
Keywords
- Chalk
- interface
- Shear
- Renewable energy
- marine energy
- concrete
Cite this
}
Characterising chalk-concrete interfaces for offshore renewable energy foundations. / Ziogos, A.; Brown, M. J.; Ivanovic, A.; Morgan, N.
Engineering in Chalk: Proceedings of the Chalk 2018 Conference. ed. / J. A. Lawrence; M. Preene; U. L. Lawrence; R. Buckley. London : ICE Publishing, 2018. p. 521-527.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
TY - GEN
T1 - Characterising chalk-concrete interfaces for offshore renewable energy foundations
AU - Ziogos, A.
AU - Brown, M. J.
AU - Ivanovic, A.
AU - Morgan, N.
PY - 2018
Y1 - 2018
N2 - Deployment of renewable energy foundations, be it piles or gravity based structures, may come into contact with chalk in southern UK waters and in other parts of European offshore and nearshore deployment. To aid more appropriate design it is useful to understand the interface shear strength between the foundation and the underlying rock where this is exposed at surface or where the foundation penetrates. In this paper, the interface shear strength between chalk and unbonded concrete is investigated for constant normal stress conditions over a range of normal stresses using tilt table and specialised interface shear testing apparatus. The results show that the interface strength of chalk is significantly influenced by the normal stress used during testing where at lower stresses the interface strength exceeds the basic friction angle determined for a chalk-chalk interface and degradation of the interface strength below the basic friction angle occurs when normal stresses exceed 73% of the tensile strength of the chalk material. This degradation is more severe at small displacements than previously observed for chalk-steel interfaces. At low normal stresses and displacements, the shear strength of the chalkconcrete interface can be represented by an alpha type approach related to the chalk unconfined compressive strength as previously developed for higher strength rocks.
AB - Deployment of renewable energy foundations, be it piles or gravity based structures, may come into contact with chalk in southern UK waters and in other parts of European offshore and nearshore deployment. To aid more appropriate design it is useful to understand the interface shear strength between the foundation and the underlying rock where this is exposed at surface or where the foundation penetrates. In this paper, the interface shear strength between chalk and unbonded concrete is investigated for constant normal stress conditions over a range of normal stresses using tilt table and specialised interface shear testing apparatus. The results show that the interface strength of chalk is significantly influenced by the normal stress used during testing where at lower stresses the interface strength exceeds the basic friction angle determined for a chalk-chalk interface and degradation of the interface strength below the basic friction angle occurs when normal stresses exceed 73% of the tensile strength of the chalk material. This degradation is more severe at small displacements than previously observed for chalk-steel interfaces. At low normal stresses and displacements, the shear strength of the chalkconcrete interface can be represented by an alpha type approach related to the chalk unconfined compressive strength as previously developed for higher strength rocks.
KW - Chalk
KW - interface
KW - Shear
KW - Renewable energy
KW - marine energy
KW - concrete
UR - http://www.scopus.com/inward/record.url?scp=85067663900&partnerID=8YFLogxK
U2 - 10.1680/eiccf.64072.521
DO - 10.1680/eiccf.64072.521
M3 - Conference contribution
SN - 9780727764072
SP - 521
EP - 527
BT - Engineering in Chalk
A2 - Lawrence, J. A.
A2 - Preene, M.
A2 - Lawrence, U. L.
A2 - Buckley, R.
PB - ICE Publishing
CY - London
ER -