Numerical simulation study on tensile-compressive mechanical characteristics of deep pre-cracked anchored soft rock
The mechanical properties of anchored soft rock are considered as an important basis for con-trolling the stability of surrounding rock in deep soft-rock roadways.Based on the discrete element soft-ware PFC,a Burgers bonded model was constructed to simulate the mechanical behavior of deep soft rock,and a numerical model of pre-cracked anchored soft rock under tensile-compressive composite stress was established to investigate the mechanical properties of anchor bolts and anchored rock and the distribution pattern of inclination angle of new cracks in anchored soft rock with different initial crack in-clination angles.Ultimately,a linear regression model of axial strain with the inclusion of pull-out loads and crack angle parameters was established for the purpose of predicting the development of axial strain in anchored soft rock.According to the research findings,the axial force and the surface shear stress of anchor bolts at cracks will be reduced to varying degrees under different crack angles,and their reduc-tions both reach the peak under the crack angle of 45°.In this case,the tensile-compressive composite stress induces the highest failure propensity of anchored rock at the anchor-rock contact interface.As the angle between the pre-fabricated crack and the anchor bolt decreases,the axial strain of the anchored rock gradually rises,and it varies linearly with the crack angle and the pull-out load under the action of the tension-compressive composite stress.As the angle between the pre-fabricated crack and the anchor bolt decreases,the number of new cracks gradually grows.Their angles are mostly about 45° and 135°,and only few of them are perpendicular or parallel to the anchor bolt.
deep soft rockanchored rockpre-fabricated cracktensile-compressive composite stressmechanical propertiesdiscrete element simulation
万方数据
维普
