Seismic behaviour of square lined underground structures

The case of elastic lined square underground structures in a homogeneous isotropic elastic medium under seismic excitation is hereby examined and the peak sectional forces and moments exerted on the lining investigated. A two-dimensional finite-difference model is used to study the effect of the structure depth, the frequency of the excitation and the flexibility ratio of the soil-structure system. A comparison with the pseudo-static method (Simplified Frame Analysis Model) is also performed. The results of all analyses have shown that seismic excitation causes sectional forces/moments that depend strongly on the structure depth, the flexibility ratio, and the frequencies of the shear wave. Furthermore, the pseudo-static as compared to the dynamic method has proved inefficient under specific circumstances. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. "Reprinted with permission from Elsevier".