Pipeline Economy Through Design of Backfill

Some methods for the structural design of soil-pipe interaction systems are reviewed and correlated. These methods include wall crippling for which ring compression is an adequate means of analysis under many conditions, and ring deflection. Because precise analysis is not usually justified, practical rules of thumb are proposed for average design based either on wall crippling or ring deflection. Maximum pressure concentrations are evaluated as a worst condition for design when wall crippling controls. Control of ring deflection by compaction of the backfill near the pipe is described. Reduction of soil pressures on the pipe by control of soil compaction near the pipe is proposed. The technique may result in a significant increase in the allowable height of fill on the pipe with consequent economy.