Research on artificial lateral boundaries in the numerical seismic analysis of underground structures.

Artificial lateral boundary is important in the numerical simulation of seismic responses of underground structures. In this paper, the performance of three commonly artificial lateral boundaries (i.e., tied boundary, fixed boundary and roller boundary) are compared based the nonlinear finite element simulation of an underground structure-soil system. The accuracy of the three artificial boundaries is discussed in terms of structural racking deformation and acceleration responses. For each artificial boundary, the influence of distance away from underground structure is discussed. The results show that when the distance from the edge of the structure to the lateral artificial boundary is more than 9 times its own width, the simulation errors of all kinds of artificial boundary are less than 5%. Among the three types of artificial boundaries, the calculation accuracy of roller boundary is best. Its distance is 3 times the width of the structure, which can satisfy the calculation error of both the structural acceleration response and the inter-story drift response within 5%. [ABSTRACT FROM AUTHOR]