| The destruction of jointed rock masses is the main cause of geological disasters.Therefore,it is very important to study the strength of jointed rock masses.The strength of jointed rock mass is not only controlled by joints,but rock bridges also play a vital role.For rock bridges,the study of its length is a more popular direction,but the study of its inclination angle is somewhat weak.Therefore,this article takes the jointed rock mass as the research object,and studies its influence on the strength of the rock mass and its scale effect according to the change of the rock bridge inclination angle.Numerical simulation is carried out through the finite element software RFPA to obtain the strength of the rock mass under a series of sizes and different rock bridge inclination angle models,reveal the influence of the rock bridge inclination angle change on the rock mass strength and its scale effect,and determine the influence of the rock bridge inclination angle under lateral pressure.Research on the influence law of rock mass strength.Through a series of experimental studies,the following conclusions can be drawn:1.It is shown by the uniaxial compression test under a single sizeThe inclination angle of the rock bridge has an influence on the uniaxial compressive strength of the rock,and with the increase of the inclination angle of the rock bridge,the uniaxial compressive strength of the rock shows a downward trend;The uniaxial compression failure process of a rock mass containing a rock bridge is mainly divided into three stages: the compaction stage of the rock mass,the stage where small cracks appear at the end of the joint,and the through failure stage.As the inclination angle of the rock bridge increases,the deflection time of the model moves forward during the failure process,and the degree of deflection also deepens;The existence of lateral pressure will increase the uniaxial compressive strength and residual strength of the rock-bearing rock mass,but the influence law of the rock bridge inclination on the uniaxial compressive strength of the rock mass is the same as the influence law without lateral pressure.2.It is shown by the direct shear test under a single sizeThe inclination angle of the rock bridge will affect the shear strength of the rock mass.As the inclination angle of the rock bridge increases,the shear strength of the rock mass decreases first and then increases;The shear failure process of rock mass containing rock bridges is mainly divided into three stages: the compaction stage of the rock mass,the stage where small cracks appear at the ends of the joints,and the through failure stage.The rock bridge with a smaller inclination has a greater impact on the failure of the rock mass;The existence of lateral pressure will increase the shear strength and residual strength of the rock mass,but the influence law of the rock bridge inclination on the shear strength of the rock mass is the same as that when there is no lateral pressure.3.It is shown by uniaxial compression test under series sizeThe uniaxial compressive strength of rock masses containing rock bridges has a Scale effect;The change of the rock bridge inclination angle will affect the Scale effect of the uniaxial compressive strength of the rock mass.As the rock bridge inclination angle increases,the Scale effect will be weakened;Obtain the formula between the uniaxial compressive strength of the rock mass and the size and rock inclination angle,which provides a scientific basis for the engineering design.4.It is shown by direct shear test under series sizeThe uniaxial compressive strength of rock masses containing rock bridges has a Scale effect;The change of rock bridge inclination will affect the Scale effect of rock mass shear strength.As the inclination angle of the rock bridge increases,the Scale effect of the shear strength of the rock mass is weakened first and then enhanced;The formula between rock shear strength and size and rock inclination is obtained,which provides a scientific basis for engineering design. |
