Efficiency of types of reinforcement systems for existing foundations (footings and piles)

Construction near existing structures can induce ground movements that compromise foundation performance, including excessive settlements and loss of bearing capacity. This study evaluates reinforcement strategies for deteriorated shallow footings and pile foundations under combined vertical and lateral loads. Reinforcement is achieved by transferring loads to deeper, more stable soil strata. A finite element analysis simulated soil-structure interaction and assessed total and differential displacements. Cylindrical Type Sheet Piles (CTSP) were installed at varying depths and inclinations, and compared with Deep Cement Mixing (DCM). For footing foundations, CTSP installation reduced horizontal displacement by 72-80% and vertical settlement by 96-98 %. Additional reinforcement using H-beams and inclined CTSP slightly varied reduction, with horizontal displacement decreasing 22-72 % and vertical settlement 23-96 %. For pile foundations, CTSP reduced horizontal displacement by 93-95 % and vertical settlement by 97 %, while DCM provided an economical alternative with 81 % and 86 % reduction, respectively. Increasing CTSP embedment depth from 10 m to 20 m further minimized displacement, particularly in pile foundations. These results provide quantitative guidance for selecting optimal reinforcement systems to enhance stability and performance of existing foundations under complex geotechnical conditions.