This Paper demonstrates the evaluation of stress distribution below a layer of load bearing geocells using the Huang’s analysis for a two layered system to evaluate deflections at the interface of the two layers, and the Authors have extended the analysis to determine the stresses at the interface.  The proposed technique does not require any sophisticated analytical tool or software other than Huang’s curves based on elastic theory.

When a vertical pressure over a limited area, such as from a footing is applied onto a geocell panel, wide-angle load spread is a phenomenon has been observed by several researchers and geocell organizations through field and laboratory tests.  The geocell panel develops its rigidity through infill of congruous geocells as well as the vertical curvilinear geocell walls which are rhomboidal in plan.  The composite structure is quite complex for analyses through conventional mechanics.

One solution lies in considering the geocell layer as yet another soil layer over the subgrade as a second layer.  The elastic characteristics of the infilled geocell are different from the underlying subgrade material.  A geocell for load bearing applications is a composite of a three-dimensional HDPE cellular structure infilled with non-plastic soil; far from an isotropic material, elastic or otherwise.  To begin with, Burmister’s two layer theory is being considered with assumptions.

Where geocells are concerned, the objective is to determine the spatial extent to which they are effective.  This is best determined by computing the stresses along the interface between the geocell layer and the subgrade and determine the distance at which the stresses due to the externally imposed loading die out.

It is a proven point that the modulus of a non-plastic soil significantly improves when it is infilled within the confines of a geocell system.  This has been earlier proven through tests by researchers and by Strata Geosystems.  This improvement is cited as the “Modulus Improvement Factor”, MIF.  The improvement in the modulus value extends beyond the height of the geocells.  The Authors has considered a MIF of 2.5 in many cases, but it is best to compute the improved E value from conventional cyclic plate load tests on infilled geocell layer at the project site itself.  The solution for geocell on a subgrade may be approached through Burmister’s solution as a two layer problem.  Burmister’s solution does not reflect the extent to which the geocell is effective.  With the help of curves derived by Huang as an extension of Burmister’s analysis, one can determine deformations below the geocell layer and thereby the stresses and their distribution.  Analysis indicates that the spread of stresses below the geocell layer is dependent on the size of the loaded area.