Time-dependent characteristics of strength and deformation of a mudstone

The mechanical properties of soft sedimentary rock, which is extensively distributed in Japan, vary according to the constituent grains and their degree of consolidation, nevertheless the influence of the pore water contained in voids is common to virtually all soft rocks. They also display strain softening and creep behavior which are the causes of progressive and delayed failure. The fundamental studies on these characteristics have been carried continuously on. Above all, Akai & Adachi et al. have continued experimental research into characteristics of porous tuff, and have released results of interest(l979, 1980 etc.).