A shakedown limit calculation method for geogrid reinforced soils under moving loads: Fid-Bau Portal

A shakedown limit calculation method for geogrid reinforced soils under moving loads

Connolly, D.P. / Yu, H.S.

Abstract A method to calculate the elastic shakedown limit of transportation systems (e.g. pavements and railways) supported by geogrid reinforced soils is presented. For the first time, lower-bound shakedown theory is combined with a strength-based geogrid simulation approach, resulting in a rapid method to quantify the benefit of geogrids on the elastic shakedown limit. It allows decoupling of elastic stress generation and shakedown calculations, meaning it is straightforward to implement, and requires minimal computational effort. Therefore it presents a useful tool to optimise geogrid design for transportation structures such as highway pavements and railways. To show the capability of the method, shakedown limits are calculated for a variety of geogrid configurations using elastic stresses induced by a moving Hertz load. The effect of geogrid depth, soil cohesion, soil friction angle and loading type (normal versus tangential) are investigated for reinforced and non-reinforced soils. It is found that the optimum depth is sensitive to the soil strength properties. Regarding loading, it is shown that for highly tangential loads, shallower geogrids are effective, while for loads with a minimal tangential component, deeper geogrids are effective.

Highlights • A new method is presented to analyse the shakedown limit of geogrid reinforced soil. • Method combines shakedown limit analysis with a strength-based geogrid approach. • Useful for the design of highway pavements and railway structures. • Allows for optimising the depth of geogrid for different soil properties. • Shown that depth, friction angle, cohesion and loading type effect geogrid performance.