In this study a comprehensive set of PULLOUT tests were conducted on geogrid. Apart from measuring the interface properties (i.e., the internal friction angle and dilatancy angle) between the geogrid and two soils, some interesting results concerning the mechanisms behind the behavior of reinforcement in PULLOUT tests were obtained.

This paper presents the results of PULLOUT tests on uniaxial geogrid embedded in silica sand under monotonic and cyclic PULLOUT forces. The new testing device as a recently developed automated PULLOUT test device for soil-geogrid strength and deformation behavior investigation is capable of applying load/displacement controlled monotonic/cyclic forces at different rates/frequencies and wave shapes, through a computer closed-loop system. Two grades of extruded HDPE uniaxial geogrids and uniform silica sand are used throughout the experiments. The effects of vertical surcharge, sand relative density, extensibility of reinforcement and cyclic PULLOUT loads are investigated on the PULLOUT resistance, nodal displacement distributions, post-cyclic PULLOUT resistance and cyclic accumulated displacement of the geogrid. Tell-tale type transducers are implemented along the geogrid at several points to measure the relative displacements along the geogrid embedded length. In monotonic tests, decrease in relative displacement between soil and geogrid by increase of vertical stress and sand relative density are the main conclusions; structural stiffness of geogrid has a direct effect on PULLOUT resistance in different surcharges. In cyclic tests it is observed that the variation of post-cyclic strength ranges from minus 10% to plus 20% of monotonic strength values and cyclic accumulated displacements are increased as normal pressure increase, but no practical specific comment can be made at this stage on the post-cyclic strength of geogrids embedded in silica sand. It is also observed that in loose sand condition, the cyclic accumulated displacements are considerably smaller as compared to dense sand condition.

This paper presents a recently developed automated PULLOUT apparatus for soil-geogrid strength and deformation behavior investigation. The new apparatus is capable of applying load/displacement controlled monotonic/cyclic loads at different rates/frequencies, different wave shapes and loading patterns, through a computer closed-loop system. An extruded uniaxial geogrid and silica sand are used throughout the experiments. The effects of normal pressure (surcharge) and relative density are investigated on displacement distributions and PULLOUT capacity of the geogrid in both monotonic and cyclic tests.In monotonic tests, it is observed that with increase in relative density and surcharge, PULLOUT resistance has increased. In cyclic tests, despite some minor observations of post-cyclic strength increased, no specific comment can be made at this stage on the post-cyclic strength.

1. Introduction: Soil nailing is regarded as one of the cast-in-place reinforcement methods for soil slopes to limit the deformation and increase its safety the use of which is considerably increasing due to some advantages such as short-term construction and low-cost implementation. This method is commonly used in compact and dense soils, as well as slopes where heavy machinery is difficult to access, although its use is limited in loose soils. The reason for using this method in dense soil is that the fine particles are less in this type of soil and have poor cementation, which itself causes little adhesion in the soil. In addition, a proper interaction results from the friction between the soil and the nail wall in this soil...

In this study, the displacement finite element method was employed to evaluate the load-displacement response and estimate the ultimate PULLOUT capacity of anchor plates. A detailed comparison was conducted between conventional and non-conventional shaped single-plate and multi-plate horizontal anchors. The analysis focused on square and plus-shaped anchors, examining the influence of anchor geometry, embedment depth, plate thickness, tie rod diameter, soil relative density, and spacing between plates on their PULLOUT performance. The results indicated that PULLOUT capacity increases with greater relative density, plate thickness, and embedment depth but decreases with larger tie rod diameters. Square anchors demonstrated 15–40% higher PULLOUT capacities than plus-shaped anchors due to their larger contact area. Multi-plate configurations significantly improved PULLOUT resistance compared to single plates, with critical plate spacing optimizing performance: 1.5b for square anchors and 1b for plus-shaped anchors. For dense sand, plus-shaped multi-plate anchors exhibited comparable PULLOUT capacities to square single-plate anchors despite a 25% reduction in anchor area. At an embedment depth of 15 m, square triple-plate anchors achieved a PULLOUT capacity of 360.6 MPa, while plus-shaped anchors reached 256.8 MPa. Stress distribution analysis revealed localized failure patterns above the anchors, with higher stress concentrations near the plates. These findings highlighted the effectiveness of multi-plate configurations and optimized geometries in improving anchor performance, offering practical solutions for geotechnical applications requiring high PULLOUT resistance in sandy soils. Overall, plus-shaped double-plate and triple-plate anchors can effectively replace square-shaped single-plate anchors.