Lateral Seismic Pressures for Design of Rigid Underground Lifeline Structures

An analytical solution and simplified design procedure is presented for evaluating the lateral seismic stress distribution and resultant force on a rigid buried structure embedded within an infinitely deep soil layer subjected to vertically propagating seismic shear waves. The solution improves upon previous models, which assume the rigid retaining structure is bonded to a rigid foundation and the top of structure is coincident with the ground surface, by incorporating more realistic foundation conditions and allowing for the determination of lateral stresses on structures having the top buried a depth d below the ground surface. The soil in the structure vicinity is modeled as a continuum and incorporates soil stiffness variation with confining pressure. The proposed model provides lower stresses on rigid walls than the previous models, mainly because of different boundary conditions for site response, but provides comparable results with the previous solutions when similar soil and boundary conditions are employed. The model presented herein improves the seismic design and assessment of lifeline systems.