Undrained test, long time

The long-time undrained test for a double-porosity system should also produce the same physical results as a single-porosity system (assuming only that it makes sense at some appropriate larger scale to view the medium as homogeneous). The conditions for this test are that from which follow These require that the overall pore-pressure buildup coefficient be given by  

 562#562 (231)

and that the undrained bulk modulus be given by  

 563#563 (232)