TY - JOUR

T1 - A new method for the analysis of foundation behavior in sand under drained high-cycle loading

AU - Cao, Shuhan

AU - Abdel-Rahman, Khalid

AU - Achmus, Martin

N1 - Funding Information: Open access funding enabled and organized by Projekt DEAL.

PY - 2023/6/14

Y1 - 2023/6/14

N2 - In offshore technology, especially in offshore wind energy converters, permanent deformations of the structures must be limited. For that purpose, the accumulation of permanent deformation due to cyclic loading must be predicted as accurately as possible. To account for this accumulation in non-cohesive soils, different approaches such as semi-empirical methods, p-y curve methods and numerical methods are available. Among the numerical approaches, the Stiffness Degradation Method (SDM) has the advantage of practical feasibility. However, it is only compatible with a relatively simple constitutive law and does not consider the influence of un- and reloading stress paths in the soil. With the basic concept of SDM, a new method termed Cyclic Strain Accumulation Method (CSAM) is proposed. In CSAM, the weaknesses of SDM, especially its incompatibility with advanced constitutive laws, are overcome, while retaining the practical feasibility as the main advantage of SDM. Through numerical calculations of a monopile, it is found that the CSAM is able to reproduce SDM results if the same material law is applied. The results of SDM and CSAM for the case of a vertical loaded strip footing have been presented. The comparison shows that the CSAM results are more realistic than the SDM results. Besides, CSAM is computationally more efficient and open for further optimisation. The effects of sophisticated material law and the consideration of un- and reloading are investigated. Results show that CSAM is a promising new approach to account for the deformation of foundations under cyclic loading in non-cohesive soils.

AB - In offshore technology, especially in offshore wind energy converters, permanent deformations of the structures must be limited. For that purpose, the accumulation of permanent deformation due to cyclic loading must be predicted as accurately as possible. To account for this accumulation in non-cohesive soils, different approaches such as semi-empirical methods, p-y curve methods and numerical methods are available. Among the numerical approaches, the Stiffness Degradation Method (SDM) has the advantage of practical feasibility. However, it is only compatible with a relatively simple constitutive law and does not consider the influence of un- and reloading stress paths in the soil. With the basic concept of SDM, a new method termed Cyclic Strain Accumulation Method (CSAM) is proposed. In CSAM, the weaknesses of SDM, especially its incompatibility with advanced constitutive laws, are overcome, while retaining the practical feasibility as the main advantage of SDM. Through numerical calculations of a monopile, it is found that the CSAM is able to reproduce SDM results if the same material law is applied. The results of SDM and CSAM for the case of a vertical loaded strip footing have been presented. The comparison shows that the CSAM results are more realistic than the SDM results. Besides, CSAM is computationally more efficient and open for further optimisation. The effects of sophisticated material law and the consideration of un- and reloading are investigated. Results show that CSAM is a promising new approach to account for the deformation of foundations under cyclic loading in non-cohesive soils.

KW - cyclic deformation

KW - cyclic strain accumulation method (CSAM)

KW - finite element method (FEM)

KW - monopile

KW - offshore wind energy converter

KW - stiffness degradation method (SDM)

UR - http://www.scopus.com/inward/record.url?scp=85153596899&partnerID=8YFLogxK

U2 - 10.1002/nag.3542

DO - 10.1002/nag.3542

M3 - Article

AN - SCOPUS:85153596899

VL - 47

SP - 1876

EP - 1893

JO - International Journal for Numerical and Analytical Methods in Geomechanics

JF - International Journal for Numerical and Analytical Methods in Geomechanics

SN - 0363-9061

IS - 10

ER -