Localized Deformation, Bifurcation Analysis Of The Theoretical Studies Of High-porosity Rocks

Many localized deformation exist in the crust. Understanding the formation and the evolution of these deformation are fundamental to geophysics and tectonics. Porous rock is not only the major subject of kinds of movement of crust but also the carrier of fluid and minerals. Therefore, investigation of the localized deformation of high porous rock is important for studying the deformation of the crust and geology action. Three types of localized deformation of high porous rock: compression zone, shear zone and dilatation zone have been found in the field, and compression zone and shear zone have been confirmed in labs. With the bifurcation analysis theory by Rudnicki and Rice (1975) and the improvement to this theory by Issen and Olssen, Fssen and Olssen (2001) proposed a new set of justify conditions of localized deformation zones. This article introduce the "cap yield curve model", simplify the cap yield surface and plastic potential energy surface by ellipse and circle, and get a new justify condition. After verifying the rationality an discussing the advantage of this model, the new model is thought to have a better applicability than older one. Besides, this article analyze amount of tri-axis compression experiments of high porous rock, and study some figures of stress-strain curve. It also discusses the segments of whole stress-strain curve, investigates the "stress-flat", which relates to the compression zone. It also studies the acoustic emission.