Geometric factors influencing the optimal position of geogrid reinforcement

The behaviour of geogrid-reinforced clay liners, subject to differential settlement, was investigated using finite element (FE) analyses. The optimal geogrid reinforcement strategy for a liner was determined by generating a Pareto front of maximum liner tensile strain versus total cost of reinforcement. To conduct the number of FE analyses required as input for the optimisation algorithm would have been too expensive. Thus, a surrogate surface was generated with a limited number of FE analyses. This surface was used to interpolate the problem’s response. The optimal reinforcement strategy (ORS) was found to be insensitive to landfill height (overburden pressure) and the clay liner thickness. The width, depth and shape of the imposed settlement trough did however influence the ORS. These preliminary results recommends reinforcement of the liner at both the bottom and the top quarter.