The pattern transition in stress-strain relations of soils

which is a mechanical phenomenon generally existed in many soils

is revealed for the first time

based on analyzing the data of stress-strain relation tests published in literatures. Two new parameters

post-failure Modulus Epost and critical confining pressureσ3cr

are suggested for recognizing of pattern transition of stress-strain relations of soils. The factors influencing the phenomenon of pattern transition such as soil types

confining pressure

initial density or water content

drainage conditions

stress paths

etc.

are briefly analyzed. Finally

a combined model for describing the pattern transition in stress-strain relations of sands is schematically suggested.