Search

AbstractHelix Stiffened Cement Mixing (HSCM) piles were a new type of composite pile developed in recent years, synchronized with grouting during the installation of helical piles to form a composite pile comprising cement soil. In this study, HSCM piles were installed in groups. This study evaluated the compressive bearing capacity of HSCM pile groups with varying numbers of piles (2, 3, and 4) and different cap configurations (high cap and low cap) in clay soil using laboratory model tests. The load-displacement curves, group pile effect, and load sharing by the cap were analyzed, and finite element models were created for further analysis. Increasing pile spacing enhances the influence of pile number on the ultimate bearing capacity of HSCM pile groups. At higher pile spacings, the group pile effect became minimal or negligible. Furthermore, for low cap HSCM pile groups, the cap distributes the load more effectively, thereby increasing the ultimate compressive capacity. [ABSTRACT FROM AUTHOR]

Helix stiffened cement mixing (HSCM) piles are extensively utilized in soft soil sites due to their excellent seismic and pullout resistance. Initially, the equivalent nodal force formulas for each face under the oblique incidence of SV waves in any spatial direction are derived based on the viscous-spring artificial boundary. The method's applicability in studying pile–soil interactions is verified based on existing pile–soil tests. Subsequently, the HSCM pile–soil model is constructed using finite element software through a Python program. Various analyses of accelerations, relative displacements, soil reactions, and pile–soil dynamic p-y curves are conducted using two different directions of incidence angles (horizontal and vertical) and various types of seismic waves. Subsequently, the backbone line of the dynamic p-y curve is plotted, revealing the pile–soil interaction mechanism under spatial oblique incidence. Finally, Matlock's formula is modified to ensure its applicability to pile–soil interactions under spatially oblique incidence. The results demonstrate that loading the Kobe wave causes the peak acceleration in the x direction, the peak pile–soil relative displacement, and the peak pile-side soil reaction force to increase by 22.64 %, −18.90 % and 18.42 %, respectively, compared to those of the El Centro wave. [ABSTRACT FROM AUTHOR]

Helix Stiffened Cement Mixing (HSCM) pile represents a novel type of grouted composite pile known for its excellent compressive and tensile performance. Based on field tests, this study introduces a laboratory-based test design methodology and piling technique for HSCM piles. A comprehensive analysis of their horizontal bearing capacity, pile-soil failure mode, optimal piling technique, and reinforcement mechanism is performed. SEM-EDS technology is utilized at a microscopic scale to examine the reinforcement mechanism of HSCM piles. Through ABAQUS finite element simulation, a full-scale model simulating the HSCM pile-soil interaction is developed. The analysis includes pile cross-sectional stress, displacement, and pile-soil failure mode. The p−y curve of the HSCM pile is then plotted, elucidating the reinforcement mechanism of cemented soil. The results indicate that compared to ordinary helical piles, the horizontal bearing capacity of HSCM piles increases by 125.9%. SEM-EDS images reveal that cement and kaolin form a mutual bond, enhancing the strength of the soil around the pile. Additionally, unlike other composite piles, the direction of soil flow around HSCM piles encircles the first helix of the pile core. This research offers a design basis for understanding the horizontal bearing performance and failure mechanisms of HSCM piles in marine soft soil. • The optimal pile formation parameters for HSCM piles are proposed. • The lateral load bearing mechanism of HSCM piles is analyzed. • The enhancement mechanism of HSCM piles is analyzed by SEM-EDS and test. • Failure modes of HSCM piles under lateral loads are obtained. [ABSTRACT FROM AUTHOR]