The contour method of tracking the trajectory of rock crack propagation was embedded into extended finite elements (EFE) platform of ABAQUS to simulate the process of initial crack extension under uniaxial pressure. The result testifies the effective of the simulation method. Then

the arc-circular fracture stress strength factor was embedded into the EFE platform. Using the maximum circumferential tensile stress criterion as cracking criterion

when the stress is greater than that rock fracture toughness

the initial crack within surrounding rock begins to extend. Based on this

a numerical simulation of the simplified round tunnel is carried out with the model test which the zonal disintegration phenomenon is observed. During the simulation process

the subdomain precise integration is adopted to improve the precision. The simulation results show that there appears 3 to 4 layer zonal disintegrations surrounding the deep tunnel. The numerical simulation indicates that there exists zonal disintegration phenomenon in deep surrounding rock mass. Comparing the numerical simulation with the ruin pattern of tunnel model after the model test

it is found that the distribution character is in coincidence with each other. The numerical simulation results show that the EFE method is effective in dealing with the problems of complex fracture in rock mass.