ABSTRACT
The relative research on the relaxation of rockmass at home and abroad began from the excavation of the tunnel, and the relaxing zone, the compaction zone and the original rock zone usually had been partitioned mainly based on the change of stress for rockmass. Similarly, the relaxation of slope is refer to the behavior or the phenomena about the relaxation of rockmass because of the change of rock stress during excavating. This chapter discusses the variety of differential principal stress tensor and the change regulation or distribution of plastic zone to clarify the mechanical character of the relaxing zone due to excavation. The rockmass in the plastic relaxing zone step into plastic state, joints splay and slip within which, and the volume of rock mass increases, the elastic wave speed value decreases, the carrying capacity of relaxing zone weakens, and then the reside strength can be used to simulate their mechanical character.
