Geofoam has been used to control loading on rigid buried pipes by development of an induced trench condition (Vaslestad 1991). It is also feasible to consider reducing stresses on large flexible culverts by placement of geofoam.

References :

Valslestad, J., (1991). "Load Reduction on Buried Rigid Pipes." 10th European Conference on Soil Mechanics and Foundation Engineering, Vol. 2, Florence, May 1991.