NEHRP Clearinghouse

APOLLO - A Computer Program for the Analysis of Pore Pressure Generation and Dissipation in Horizontal Sand Layers During Cyclic or Earthquake Loading.
Martin, P. P.; Seed, H. B.
National Science Foundation, Washington, DC., October 1978, 68 p.
Identifying Number(s)
Several methods of expressing the rate of build-up of pore water pressures in a sand deposit subjected to earthquake shaking have been developed in recent years. They generally fall into one of two categories: (1) By referring to the fundamentals of the behavior of granular materials under cyclic shear stress applications, it has been possible to isolate the factors and the soil properties which determine the rate of pore water pressure generation. Then these data and mechanisms have been incorporated into methods of effective stress ground response analysis. Yet, unless these basic soil characteristics can be measured with the required degree of accuracy, predicted pore pressures may be somewhat in error. (2) Use can be made of actual measurements of pore water pressure build-up in cyclic loading tests. The only criteria then required to evaluate pore pressure development in any soil element is the evaluation of the number of uniform stress cycles which will produce a condition of initial liquefaction under undrained conditions. This can readily be determined from undrained cyclic simple shear tests or other appropriate tests on representative samples. A method of evaluating soil pore pressure generation and dissipation in horizontal sand deposits subjected to earthquake shaking using the principles described in (2) above has been developed and shown to give reasonable results in comparison with the known behavior of the soil at Niigata, Japan in the earthquake of 1964. This report describes the computer program APOLLO, in which the method has been incorporated, and gives a typical example of its application.
APOLLO computer program; Computer programming; Pore pressure; Earthquake engineering; Water table; Stress analysis; Earthquakes; Soil dynamics; Liquefaction (Soils); Mathematical models; Cyclic loads