岩石试件端面效应的变形局部化数值模拟研究

试件端面效应直接影响试件内的应力分布、试件破坏形式和剪切带图案。采用FLAC - 3D模拟了端面效应对岩石试件剪切带图案、速度场和位移场的影响。试样端部的缚束作用较强时 ,仅在试样中部出现X形的剪切带 ;反之 ,在试样端部出现了倾斜的剪切带。压头刚性越大 ,剪切带倾角越大。块体具有整体平移的特性 ,剪切带边缘位移梯度却较大 ,反映了块体沿剪切带发生滑动的剪切破坏本质。数值模拟结果可在众多的试验结果中找到佐证。

NUMERICAL SIMULATION ON STRAIN LOCALIZATION OF END CONSTRAINT OF ROCK SPECIMEN

End constraint has an influence on distribution of stress in rock specimen, failure pattern and pattern of shear zone. FLAC-3D is adopted to simulate the influence of end constraint on patterns of shear bands, velocity and displacement fields. For a stiffer constraint, a conjugate shear zone occured in central part of the specimen; Otherwise, an inclined shear zone initiated on the end of the specimen. The inclination angle of shear zone becomes steeper with increasing rigidity of platen. Four small blocks have properties of integral movement. The displacement gradient along the margin shear zone is larger. It shows that the blocks slide alone shear zone is of shear failure nature. The result of numerical simulation is consistent with some experimental results.