The Theory Study On Creep Stability Of Rock Structure

The structure of rock is extremely complicated discontinuous and heterogeneous body, its mechanics property has non-linear, anisotropism and rheology characteristic, which changed over time. The characteristic stress state of rock structure is keeping constant before its losing steady, and suddenly destroyed with releasing energy, namely creep is losing steady. So it is important theory meaning and reality value to long-term stability of rock engineering to launch research of rock creeping destroying mechanism.The text proceeds from the whole stress-strain characteristic and creep curve of rock, set up creep losing steady model, regard two parameters of model as changing with deformation of rock, draw losing steady criterion and modified creep equation, and then has explained losing steady phenomenon at the third stage of rock creep; At the same time we derived out analytical solution of the creep model from different angles, and indicate constitutive of rock and deformation of modulus which relate to the condition and history of loading, and prove that it is a perfect rheology model which can describe decay creep, stability creep and accelerate creep of rock.The text combines creep model and general solution of rheology mechanics, deriving out visco-elasto-plastic analytic solution of critical load and stress of operation goaf hanging beam, and analyzed its stability; Deriving out displacement of wall rock which increases with time changes, and has drawn radius of plasticity district; Set up losing steady beam model of slope containing weak intermediate layer, modified Euler formula has a time effect, putting forward losing steady analytical method of the slope.