Deformability and stability of the right bank rock mass along the axis of the toktogul dam

摘要

1.Blocks of rock in the disintegrated zone near the right bank abutment of the Toktogul arch dam, formed by a system of joints containing cohesive or cohesionless filling material, can function in the elastic range if the loads do not exceed a value 1.08 times the working load (for Ks=0.3) or 0.82 times the working load (Ks=0.45) (the effect of rock weight is taken into account).2.Displacements of blocks in the disintegrated zone leads to considerable redistribution of forces in the aboutments. All blocks of the disintegrated zone are involved in the shearing process and sliding takes place along a joint situated at the farthest distance from the excavated surface. The volume of material undergoing shear depends, however, on the geomechanical characteristics of the joint-filling material. When the material possesses both cohesion and internal friction the total mass involved is somewhat smaller than when only internal friction is present.3.The presence of cohesion in the joint-filling material causes only a small increase in the force required for producing displacements in the disintegrated zone. If the weight of the boulders is taken into account the magnitude of the yield force increases up to 1.27 times the working load (at Ks=0.3) or 0.97 times the working load at (Ks=0.45).4.Strengthening of the rock mass by anchors has a beneficial effect on the foundations. However, the capacity of the anchor, as envisaged in the design, may not be fully utilized. After the upper part of the integrated zone is strengthened the minimum load causing failure may be taken as 1.66 times working load for Ks=0.3 or 1.27 times working load for Ks=0.45.