Conference Paper

FLAC based 3D numerical analysis of machine foundations resting on geosynthetics reinforced layered soils

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Abstract

The behavior of the machine foundation resting on the geosynthetic reinforced soil bed is not well understood yet. The present study investigates the efficacy of geosynthetics reinforcement in supporting the machine foundations. 3D numerical studies have been performed using the explicit finite difference package FLAC3D. The behaviour of a square footing, 0.6 m wide and 0.5 m deep resting on a non-homogeneous foundation bed has been analysed. Three different cases, namely, unreinforced, geogrid and geocell reinforced conditions were considered. The analysis was carried out by varying the frequency of the excitation. The depth of placement of geogrid and geocell was varied. From the results, the opti-mum depth of placement of geogrid and geocell was found to be 0.4B and 0.1B respectively from the ground surface. Similarly, the optimum width of placement of geocell and geogrid was found to be 4B. In overall, the performance of geocell was found to be better than other conditions. In the presence of geo-cell, displacement amplitude and peak particle velocity were reduced by 44% and 42% respectively as compared to the unreinforced condition. Further, the geocell reinforcement improved the stiffness as well as the resonant frequency by 1.8 and 1.3 times as compared to unreinforced condition.

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... Venkateswarlu et al. (2018a) reported that increase in elastic response of foundation bed due to the inclusion of geocells. Few studies reported the potential using the geocell in mitigating the lateral spreading of machine induced vibration (Venkateswarlu and Hegde, 2018;Venkateswarlu et al., 2018b). ...
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... From the analysis, the lateral spreading of machine induced vibration was found to arrest in the presence of geocell reinforce-ment. The study of Venkateswarlu et al. (2018b) reported the efficacy of geogrid and geocell in improving the nonhomogeneous machine foundation bed through FLAC3D based analysis. The realistic soil profile obtained from the standard penetration test (SPT) data was used in the study. ...
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This paper presents the results of laboratory model loading tests and numerical studies carried out on square footings supported on geosynthetic reinforced sand beds. The relative performance of different forms of geosynthetic reinforcement (i.e. geocell, planar layers and randomly distributed mesh elements) in foundation beds is compared; using same quantity of reinforcement in each test. A biaxial geogrid and a geonet are used for reinforcing the sand beds. Geonet is used in two forms of reinforcement, viz. planar layers and geocell, while the biaxial geogrid was used in three forms of reinforcement, viz. planar layers, geocell and randomly distributed mesh elements. Laboratory load tests on unreinforced and reinforced footings are simulated in a numerical model and the results are analyzed to understand the distribution of displacements and stresses below the footing better. Both the experimental and numerical studies demonstrated that the geocell is the most advantageous form of soil reinforcement technique of those investigated, provided there is no rupture of the material during loading. Geogrid used in the form of randomly distributed mesh elements is found to be inferior to the other two forms. Some significant observations on the difference in reinforcement mechanism for different forms of reinforcement are presented in this paper.
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