Abstract: The computing formulas of superimposed load on adjacent level parallel pipe induced both by bulkhead additive thrust, force of friction between shield and soil, and force of friction between follow-up pipes and soil are derived from the Mindlin solution in elastic mechanics. The influences of pipe net spacing distance, pipe diameter, buried depth and soil’s Poisson ratio on the distribution of superimposed load are discussed. The analytical results show that the pressure on adjacent level parallel pipe induced by force of friction between follow-up pipes and soil is small during injecting slurry; and the peak value appears at the back of excavation face. When construction is in normal, superimposed load induced by bulkhead additive thrust is very small. For adjacent level parallel pipes, pressure is produced in front of excavation face while pull force at the back. They distributed antisymmetrically with the axes of excavation face. Superimposed load induced by force of friction between shield and soil and is much larger than that of bulkhead additive thrust with its “zero point” at the middle of shield. The force of friction between shield and soil plays a leading role, thus, it should be considered highly during construction.

Key words: parallel pipe jacking, bulkhead additive thrust, force of friction, Mindlin solution, superimposed load