P5II . 8. Buried pipes are frequently used to transport petroleum products in cold climates. The ground temperature, T, at various depths below the surface, assuming a semi-infinite solid, is given by TiTST(x,t)TS=erf)=20e2d, P5II . 8. Buried pipes are frequently used to transport petroleum products in cold climates. The ground temperature, T, at various depths below the surface, assuming a semi-infinite solid, is given by TiTST(x,t)TS=erf)=20e2d