Study On Mechanical Parameters Estimation And Size Effect Of Jointed Rock Mass

Jointed rock mass is studied in this paper.In the meantime,the scale and geological impacts on the deformation and the strength of jointed rock mass are considered here.The numerical simulation method is used to study the jointed rock mass.Numerical models of jointed rock mass with different scales in the same typical joint distribution patterns are established.The mechanical parameters,such as modulus of elasticity and strength of rock mass with different scale are calculated.The scale effect of jointed rock mass is studied and the representative elementary volumes of rock mass are estimated.After determining the representative elementary volume,this research establishes models of jointed rock mass by changing the geometric characteristics of the joints.The influence of the geometric properties of joint on the mechanical parameters of rock mass is studied under the condition of removing the scale effect.The results obtained in this research show that the representative elementary volumes of the deformation and strength parameters of jointed rock mass under the typical joint distribution models are about 18 to 20 meters.The scale of the joint space is positively related to the parameters of the mechanical properties.The correlation curves of the joint angle and the mechanical parameters of rock mass show U type.When there are many groups of joints,the mechanical parameters of rock mass will be further weakened.The correlation curves of relative joints angle and mechanical properties also show U type.The existence of through joint joints makes the rock mass show significant weakening and inhomogeneity.Xiaowan Hydropower Station is taken as the example of the research.Therepresentative elementary volume of the compressive strength,elastic modulus,cohesive force and internal friction angle of jointed rock mass in the dam site of hydropower station are determined.According to the regression curve,the mechanical parameters of the jointed rock mass under the effect of removing the scale effect are estimated.The obtained results are applied to the numerical simulation of the anchorage of jointed rock mass.The application of compaction-type prestressed anchor cable in jointed rock mass is discussed.