Effectiveness of strip footing with geogrid reinforcement for different types of soils in Mosul, Iraq

Abstract

The main cause of problematic soil failure under a certain load is due to low bearing capacity and excessive settlement. With a growing interest in employing shallow foundation to support heavy structures, it is important to study the soil improvement techniques. The technique of using geosynthetic reinforcement is commonly applied over the last few decades. This paper aims to determine the effect of using geogrid Tensar BX1500 on the bearing capacity and settlement of strip footing for different types of soils, namely Al-Hamedat, Ba’shiqah, and Al-Rashidia in Mosul, Iraq. The analysis of reinforced and unreinforced soil foundations was conducted numerically and analytically. A series of conditions were tested by varying the number (N) and the width (b) of the geogrid layers. The results showed that the geogrid could improve the footing’s bearing capacity and reduce settlement. The soil of the Al-Rashidia site was sandy and indicated better improvement than the other two sites’ soils (clayey soils). The optimum geogrid width (b) was five times the footing width (B), while no optimum geogrid number (N) was obtained. Finally, the numerical results of the ultimate bearing capacity were compared with the analytical results, and the comparison showed good agreement between both the analyses and the optimum range published in the literature. The significant findings reveal that the geogrid reinforcement may induce improvement to the soil foundation, however, not directly subject to the width and number of the geogrid alone. The varying soil properties and footing size also contribute to both BCR and SRR values supported by the improvement factor calculations. Hence, the output complemented the benefit of applying reinforced soil foundations effectively.

Analysis of the Shear Strength of a Soil-Geosynthetic Interface

“…In the case of geogrid, an increase or decrease in the soil-geosynthetics interface shear strength depends on the internal shear strength of the material within the geogrid's open area, the friction between the material and the surface of the geosynthetics, and mobilization of the resistance between the material and the transverse ribs; see e.g., [21]. The shear strength of the material within the geogrid's open area usually has no impact on the change of the interface coefficient , and the interface's shear strength is equal to the shear strength of the unreinforced material, Fig.…”

“…19, Issue 1, 452-463 see e.g. [20][21]. The actual value of the parameter  depends on the properties of the reinforced material and the parameters of the geosynthetic reinforcement.…”

Comparative Study on the Reinforced Sand-Bed and the Stone Column in Improving the Clay Deposit Supporting Isolated Footing

“…Several studies are related to these two techniques. In most of them, the geosynthetics applications focussed on bearing capacity improvement [1][2][3] and settlement reduction [3,4].…”

Finite Element Analysis for Improving the bearing capacity of Existed strip footing s ABSTRACT 1

“…Et. al., 2020) they studied numerically and analytically the effectiveness of geogrid reinforcement on the behavior of strip footings on clayey and sandy soils [9][10] . Other materials like using waste tires shreds-soil mixture beneath foundation was studied by (Gourav Gill.…”