Abstract：The disturbance scopes in lateral and vertical directions，and calculational formulas for ground settlement are gained by analyzing the rules for ground deformation induced by level parallel pipe jacking construction in one underconsolidation soil. It shows that the ground settlement produced by middle zone is greater because of double disturbance during parallel pipe jacking construction. Also，the surrounding soil disturbance due to former pipe jacking construction will strengthen the disturbance during latter pipe jacking construction. Thus，the maximal ground settlement and width of settlement tank during latter pipe jacking construction are greater than those of the former. Ground settlement due to parallel pipe jacking construction is produced not only by the ground loss but also by the reconsolidation and secondary consolidation of the disturbed soil. Excess pore water pressure from soil disturbance is the reason for post-construction settlement. Finally，post-construction settlement in underconsolidation soil is basically proportional to the logarithm of time.
