Zonal disintegration of rock mass around underground engineering is a hot research topic since discovery of it. It concerns with the stability and support of engineering at deep level. The numerical method of simulation on three dimensional models is involved. The numerical models with a circle hole and two holes taking rock heterogeneity into account under loading are adopted. The meshes for the model consists of 90×180×180=291,6000 8-nodal hexahedron elements with a geometry of 90×180×180mm in size. With the code named RFPA3D-Parallel (3-Dimensional Parallel Rock Failure Process Analysis) based on finite element method running on Lenovo 1800 Cluster with 64 CPUs, the whole process of rock fracturing of zonal disintegration (fracture spacing) is obtained. It provides a powerful numerical tool to study the problem of zonal disintegration in rock mass. The numerical results indicate that the higher axial principle stress may be one of the most important factors caused spacing fracture in rock mass around deep tunnel.
With economic and engineering developing, underground space's exploitation is going to deep level. Main results of in-situ tests of the behavior of rocks around underground workings at large depth have been published earlier. Rock mass at large depths is in the situation of high crustal stress, high temperature and high seepage pressure. The mechanical behaviors of rock mass in deep tunnels are different from those shallow tunnels. The phenomenon of zonal disintegration (see Fig.1) alternately successive distribution of fractured zone and unfractured zone around rock mass of tunnel or working face at large depthsobserved by E.I. Shemyakin et.al. is one of important and interested problems in deep rock engineering and mechanics theory. It has key influence to the excavation and supporting of tunnels and working faces. Many researchers with interests have done some work on it. And a lot of explanations about its formation have been put forward by various theories and experiments. A.M. Kozel considered the relationship the development of zonal disintegration and the dynamic process of drivage and blasting. G.G. Mirzaev related fractures parallel tunnel contour to seismic wave called Hopkinson failure. E.I. Shemyakin et al.[1,4] carried out experimental tests in their laboratory with similar material and research on engineering practical application of zonal disintegration. Their study showed that rock mechanical property, rock structure, tunnel shape and support pattern have influence on zonal disintegration and that the stress changes around tunnel not the blasting caused zonal disintegration around deep tunnel. L.S.Metlor, A.F.Morozov and M.P.Zborshchik revealed physics basics of rock fracture around tunnel with nonequilibrium thermodynamics, and represented the revolution process rock failure from elastic situation to zonal fracture structure. As viewed from energy, V.N.Reva presented an evaluation method to tunnel stability on the condition of appearing zonal disintegration.
The RFPA3D code is based on the theory of elastic-damage mechanics and FEM (finite element method). In RFPA3D, the solid or material is assumed to be composed of many elements (8-nodal hexahedral isoparametric element at present) with the same size.