In order to study the meso-damage mechanism of deep foundation of rock under complex stress conditions

the constitutive equations of the elasto-plastic meso-damage model

derived from the strain space micromechanics

were adopted in the finite element method to simulate numerically three-dimensional cracking process of the rock.The elimination of micro-damage elements was carried out in the finite element analysis to follow the extending process of cracks.The rock was loaded by displacement to its progressive failure process;the failure tests of the limestone

under loading cases of uni-axial tension/compression

bi-axial tension and tri-axial compression

were simulated numerically to obtain the nonlinear stress-strain curves and a series of images of cracking evolution at different stages of the loading

for the analysis of the influence of rock in-homogeneity on the macro-cracking mechanism of the rock.The results indicate that the peak values of compressive strength and the plastic deformation will increase significantly with the increment of the confining pressure.This study will be helpful to the prevention of engineering disasters in construction of deep foundations.