With rapid development of underground structure

it is very urgent to solve the problem of reevaluating the underground structure’s anti-earthquake stability because of many damages caused by earthquakes. Using methods of cyclic triaxial test and resonant column triaxial test

a seismic analyzing model is established in the paper which is based on the seismic stress-strain relation of Shanghai soft soil

the rising law of pore water pressure and the law of settlement induced by seism. Based on the theory of seismic response analysis by FE effective stress

the seismic analyzing model mentioned above

the dynamic reciprocity theory and the dynamic reliability theory

the analyzing method of anti-earthquake and dy namic reliability of the underground structure on Shanghai soft soils are presented. Such method is used to analyze the anti-earthquake stability of subway stations and tunnels in Shanghai. The results is not only useful to projects but also useful for designing of under-structures with anti-earthquake dynamic reliability. The aspects of dynamic response analysis include the dynamic stresses of tunnels

subway stations

injected materials and surrounding soils as well as pore water pressures and settlements of surrounding soil. The results provide reliable foundation for anti-earthquake designing of under-structure in two typical soft soil of Shanghai. The numerical test shows that: （1） In the case of Shanghai subway tunnels and stations with soft soil

the effect of an earthquake on groundstructure in 7 degree intensity area can be neglected

but the effect of an earthquake on groundstructure in 8 degree intensity area is significant

because the vibration pore pressure and the settlement of the soil in vicinity of groundstructure arc large; （2）The pore pressure ratio and the settlement of soil are sensitive to earthquake input; the dynamic shear stress and the structural stress deviate slightly for different earthquake inputs; （3）The largest tensile stress occures at the top part of a conjucture of subway station and shield-constructed tunnel

at the bottom part of which the largest compressive stress occures. In addition

the results also demonstrate that the law of soil damage caused by earthquake using accumulative damage model agrees with that of dynamic shear stress ratio and vibration pore water pressure ratio. By fitting performance analysis

it is concluded that the maximum dynamic shear stress obey the logarithmic normal curve distribution law. So it is possible to use random wave to simulate earthquake wave in dynamic reliability analysis. Thus it eliminates the limitation of using traditional earthquake wave as an input in dynamic analysis of understucture.