Response of pile groups with X and circular cross-sections subject to lateral spreading: 3D numerical simulations

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 126; p. 105774
• Main Authors: Li, Wenwen, Stuedlein, Armin W., Chen, Yumin, Liu, Hanlong, Cheng, Zhao
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.11.2019; Elsevier BV
• Subjects: Bored piles; Computer simulation; Cross-sections; Ground motion; Interaction parameters; Lateral displacement; Lateral spreading; Liquefaction; Liquefaction mitigation; Mathematical models; Nonlinear dynamics; Numerical modeling; Numerical simulations; Periodic boundary; Pile groups; Piles; Seismic response; Simulation; Slopes; Soil-pile interaction; Soils; Spreading; Structural design; Structural engineering; Unit cell; X-shaped cross-section; Numerical modeling; Piles; X-shaped cross-section; Liquefaction mitigation; Periodic boundary; Lateral spreading
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2019.105774

Recent 1-g shake table experiments have shown that the relatively new X-shaped cast-in-place piles can improve the seismic response of slopes susceptible to lateral-spreading as compared to conventional bored piles when mitigated using the pile-pinning method. This paper presents three-dimensional (3D) nonlinear dynamic numerical simulations of groups of piles with X-shaped cross-sections subjected to lateral spreading to broaden the understanding of their effectiveness in mitigating slope displacements. The unit cell method is used with the stress-ratio controlled and critical state-compatible Dafalias-Manzari model to capture appropriate cyclic behavior of the liquefiable soil surrounding the piles subjected to seismic ground motions. The numerical simulations facilitate the evaluation of various parameters controlling soil-pile interaction and the structural pile response, including the effect of pile spacing, pile fixity, pile orientation, slope angle, and geometrical effects of the pile cross-section with emphasis on the X-shaped section. The results demonstrate that X-shaped pile groups can significantly reduce lateral slope displacements compared to the unimproved or circular pile-improved ground, and that the spacing, pile orientation and pile fixity play a critical role in the deformation response. These findings provide insight to the design of pile-improved ground as well as the structural design of piling adjacent to or within liquefiable slopes. •The unit cell method is used with Dafalias-Manzari model to capture cyclic behavior of the liquefiable soil.•Various parameters controlling soil-pile interaction and the structural pile response are investigated.•X-shaped pile groups can significantly reduce the lateral slope displacements compared to the unimproved ground.•The pile spacing, pile orientation and pile fixity play a critical role in the deformation response.