The distribution regularity of total additional load on perpendicularly crossing buried pipeline induced by double parallel shields construction is studied.The calculation formulas of soil additional stress

which is induced by bulkhead additive thrust

frictional force between shield and soil and grouting pressure

are derived from Mindlin solution in elastic mechanics at the end of the shield during double parallel shields excavation.On the basis of the Winkler model

the calculation formula for vertical additional stress in soil caused by soil excavation is derived.The analytical results show:the additional load of underground pipeline caused by the frictional force and the pressure of shield tail grouting in double line shields construction is large

while the additional load caused by bulkhead additive thrust is relatively small.Soil excavation is the main cause of the vertical load.The additional load on underground pipeline above the second shield changes obviously as the distance Q between the excavation faces of the first and second shield tunnels reduces.The peak values of the additional load on the pipeline in xand zdirections reduce as the parallel distance Lbetween the first and second shield tunnels increases.