ABSTRACT
The study has carried out on the variation of pore graduation and compression volume (s) of hard clay with time (t) based on the Terzaghi Theory. We classified the pores in hard clay and the porewater in them into three types. The compression volume (s) shows periodicity with the time of consolidation. The boundary of the periods is a critical point. The consolidation rate is high at the beginning of each period, but getting slower with time, which we call it a consolidation cycle. The compress volume (s) shows correlatively with time by the form of Terzaghi Theory. But the s-t curve obtained by omitting the cycles does not fit with Terzaghi's theoretical curve well. The practical observation data of subsidence show that the consolidation parameters obtained by consolidation cycles are more approximate to actual conditions, with 10-20 times precision than that got from traditional soil tests. By the analysis of hard clay structure and evolution environment, we found that the occurrence of pores which results from the difference of evolution or environment.
