Abstract:

Fracture water lying in fractured rock mass, has been considered as a positive factor for the damage of rock wall. Rock bolts, as an effective rockmass reinforcement measure in civil and mining engineering, enhance the stability and improve the damage of jointed wall rock through restraining the formation within the rock masses. According to the damage mechanics theorem, the flexibility tensor variation may externalize the macroscopic effect of rockmass damage. Associating with the flexibility tensor of the intact material, the accessional flexibility tensor is used to show the effect of the joint on the rockmass. The seepage pressure flexibility tensor is also introduced to denote the effect of seepage pressure on the rockmass intension. The accessional stiffness is introduced to represent the enforcing effect of bolt on the rockmass, the inversion of which is the flexibility tensor. So the paper has studied systematically the coupling mechanics between the seepage field and the damage field in the anchoring jointed rockmass under seepage pressure. Based on the Betti energy reciprocal theorem and self-consistent theorem, the constitutive model for the anchoring jointed rockmass under the seepage pressure is obtained under the conditions of compression-shearing and tension-shearing. The calculation method and finite element procedure come into being according to the above model, in which half solution coupling method is applied to coupling the damage and the deformation. The above program is applied to actual project to model the ground movements that occur when the subsea tunnel is installed in the jointed rockmass. The computation results validate their validity; and the analysis indicates that the damage effect of the seepage pressure on anchoring jointed rockmass can not be ignored.

Key words: seepage pressure, constitutive equations of anchored jointed rockmass, flexibility tensor