APOLLO

Legacy software from 1978 that incorporates a simplified procedure for one-dimensional analysis of generation and dissipation of pore water pressures in a sand deposit due to seismic excitation. Source code in FORTRAN and related reports can be downloaded from the earthquake engineering online archive maintained by University of California Berkeley.

APOLLO: Analysis of Potential Liquefaction of Soil Layers for One-Dimensional Seepage

Martin, Philippe P.; Seed, H. Bolton

Department of Civil Engineering, University of California, Berkeley, 1978,

This program incorporates a simplified procedure for one-dimensional analysis of generation and dissipation of pore water pressures in a sand deposit due to seismic excitation. The method of liquefaction analysis in APOLLO is outlined by the following steps: (1) By means of a dynamic response analysis of the soil deposit under investigation, time histories of shear stress developed by earthquake are determined at the various depths of interest; (2) For each depth in the soil profile, determine the equivalent uniform cyclic stress, the equivalent number of uniform stress cycles and the effective period of each stress cycle representing the induced stress history; (3) Determine from laboratory cyclic load test the relationships between the applied cyclic shear stresses and the number of stress cycles required to produce a condition of initial liquefaction under undrained conditions; (4) Determine the number of stress cycles required to cause initial liquefaction; (5) Determine rate of pore pressure build up for each elemental layer of the deposit; (6) From a knowledge of the coefficients of permeability and compressibility of the soil layers, determine the corresponding values of the coefficient of consolidation for the different layers; (7) Solve the governing differential equation for the known values of soil characteristics, pore pressure generation expressions and boundary conditions. Program APOLLO is used to solve this equation by an implicit finite difference method.