DYNAMIC ANALYSIS OF STABILITY OF BEDDING CREETING TYPE SLOPE AT AN OPEN PIT COAL MINE

The non linear creep property of the weak layer is analyzed and the change property of its mechanics strength and the non linear property of its stress strain relationship are indicated.On the basis of the aged theory,a common creep equation- τ=A o(1+δ·t α) ·γ m(1+σ mH) is posed.Subsequently,the damage strain γ s is defined as critical value from the steady state creep rate to the increasing state creep rate,and the relationship between the long term shear strength and the stress changing rate with time- τ=A o·γ s(1+δ·t α) +A o·γ sH(1+δ·t α) ·σ m=c+σ m·tgφ is concluded.As to the instability deformation of the creeping slope,the strain rate of the steady state creep is associated with its shear stress level to exceed its shear strength limit.The property studies show that the shear strength of the weak layer decreases with time so provide an important basis for the theory analysis of the dynamic stability on the wriggling slope.