The Earthquake Engineering Online Archive

GADFLEA: a computer program for the analysis of pore pressure generation and dissipation during cyclic or earthquake loading

Booker, John R.; Rahman, M. Shamimur; Seed, H. Bolton

UCB/EERC-76/24, Earthquake Engineering Research Center, University of California, Berkeley, 1976-10, 63 pages (475/B647/1976)

During earthquakes, pore water pressures are induced in soils by the cyclic stress applications induced by the ground motions. At the same time, pore water pressures may dissipate from the soil due to drainage. Until very recently it had not been possible to couple the two effects. However, it has recently been shown that under onedimensional conditions the pore-pressure generating effects of cyclic loading could be incorporated into a dissipation analysis by the introduction of a source term. This approach has also been extended to situations involving radial flow in studies of the feasibility of using gravel drains to stabilize potentially liquefiable soil deposits. An interesting aspect of this approach is that although it was initially developed to analyze cyclic loads induced by earthquakes it is equally applicable to many other forms of cyclic loading and may thus, for example, be used to analyze pore pressure generation and dissipation induced by wave action on offshore structures. In this report a method of analysis of the equations governing pore pressure generation and dissipation based on the finite element method is developed and illustrated by application to a variety of problems.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-76-24.pdf (1 MB)