Bearing capacity of circular foundations reinforced with geogrid sheets

Abstract

The ultimate bearing capacity of a circular footing, placed over a soil mass which is reinforced with horizontal layers of circular reinforcement sheets, has been determined by using the upper bound theorem of the limit analysis in conjunction with finite elements and linear optimization. For performing the analysis, three different soil media have been separately considered, namely, (i) fully granular, (ii) cohesive frictional, and (iii) fully cohesive with an additional provision to account for an increase of cohesion with depth. The reinforcement sheets are assumed to be structurally strong to resist axial tension but without having any resistance to bending; such an approximation usually holds good for geogrid sheets. The shear failure between the reinforcement sheet and adjoining soil mass has been considered. The increase in the magnitudes of the bearing capacity factors (N c and N γ ) with an inclusion of the reinforcement has been computed in terms of the efficiency factors η c and η γ . The results have been obtained (i) for different values of ϕ in case of fully granular (c ¼ 0) and c Àϕ soils, and (ii) for different rates (m) at which the cohesion increases with depth for a purely cohesive soil (ϕ ¼ 0 ○ ). The critical positions and corresponding optimum diameter of the reinforcement sheets, for achieving the maximum bearing capacity, have also been established. The increase in the bearing capacity with an employment of the reinforcement increases continuously with an increase in ϕ. The improvement in the bearing capacity becomes quite extensive for two layers of the reinforcements as compared to the single layer of the reinforcement. The results obtained from the study are found to compare well with the available theoretical and experimental data reported in literature.

Mitigating the bridge end bump problem: A case study of a new approach slab system with geosynthetic reinforced soil foundation

“…Meanwhile, extensive experimental studies, including smallscale laboratory model tests and large-scale field tests, were conducted on geosynthetic reinforced soils by the authors in several research studies (Chen, 2007;Chen et al, 2007Chen et al, , 2009Sharma et al, 2009;Abu-Farsakh et al, 2007, 2008Chen and Abu-Farsakh, 2015) and also by other researchers around the world (e.g., Binquet and Lee, 1975;Huang and Tatsuoka, 1990;Adams and Collin, 1997;Tafreshi and Dawson, 2010;Bai et al, 2013;Demir et al, 2013;Chakraborty andKumar 2014, Miao et al, 2014;Naeini and Gholampoor, 2015). The influences of different variables and parameters contributing to the improved performance of reinforced soil foundation (RSF) were examined in these tests.…”

Planar geosynthetic-reinforced soil foundations: a review

“…By calculating the energy dissipation under the action of external forces, the energy dissipation on the cross-section, and the energy dissipation of reinforcements on the sliding surface, the ultimate bearing capacity of the reinforced foundation is finally determined. Some scholars also use the finite-element limit analysis method to evaluate the ultimate bearing capacity of reinforced foundation [92,93]. Except limit equilibrium method and limit analysis method, other analytical methods are also used to calculate the bearing capacity of reinforced foundation, including regression analysis method [30,31,41,88], finite element method [32], and slip line method, etc.…”

Applications and Performance of Geogrids in Structures

“…The bearing capacity of circular rigid foundations increases when the reinforcement and the friction angle increases. The bearing capacity is said to be high for two-layered reinforcement than single layer reinforcement [23]. The bearing capacity depends on the length of the geogrid layers.…”