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Three-Dimensional Numerical Analysis of Static and Cyclic Pull-out Response of Plate Anchors in Reinforced Soft Clay
Journal
International Journal of Geosynthetics and Ground Engineering
ISSN
21999260
Date Issued
2024-06-01
Author(s)
Subramaniam, Ravishankar
Abstract
Constructing infrastructures such as traffic and railway gantries, transmission towers, and near-shore sea walls on soft soils, demands specially designed foundation systems capable of withstanding pull-out forces. Plate anchors are crafted for such environments. It consists of a steel plate embedded in the soil and connected to the external structure through a tie-rod. These anchors have become increasingly prevalent in engineering projects designed to withstand the pull-out forces from the superstructure. The present study investigates the vertical pull-out response of embedded anchors, subjected to cyclic disturbances, using three-dimensional finite element analysis. Advanced constitutive models, including the Soft Soil (SS) model and Hardening Soil model with small-strain stiffness (HSsmall), are employed to study the non-linear and time-dependent response of soils under monotonic and cyclic pull-out loads. The numerical analysis indicates that, in addition to soil type and anchor size, the placement and nature of loading, influence the anchor capacity. It was noted that under cyclic loads, anchors buried in saturated soft soils display a non-linear hysteresis response and a degradation in pull-out resistance with loading cycles. This reduction in anchor resistance with an increment in the loading cycle is noted when the anchor is subjected to higher cyclic stresses. A series of numerical investigations were carried out to analyse the impact of reinforcing the soil above the anchor with geotextile. This approach aimed to address the challenges associated with soft soils and enhance the performance of anchor-soil foundation systems under different loading scenarios. The results highlight the substantial role of geotextile reinforcement in enhancing anchor stability and resistance against vertical pull-out and cyclic disturbances. Reinforcing the soil above the anchor plate amplifies the pull-out resistance up to 45%, in contrast to anchors placed in unreinforced soil. In addition, the anchors exhibit improved performance under cyclic loads, with an enhancement in cyclic pull-out resistance up to 29%, without causing additional degradation of the soil’s shear strength under repeated cyclic loading. This improvement in cyclic pull-out resistance is attributed to the resilient cyclic characteristics of geotextile reinforcement.
Volume
10
Subjects