Research On Anchorage Character Of Zonal Disintegration In Deep Rock Mass

With the rapid development of China’s national economy, many underground constructions being and to be build are located increasingly deeper into the earth. Underground tunnels and chambers (caverns)for exploitation of mineral resources, traffic construction as well as hydroelectric developments are gradually digging into a depth of over1kilometer or even several kilometers.Contrary to tunneling in shallow rock mass, deep tunneling would encounter zonal disintegration under the high geo-stress, thus increasing the cost of supporting. Taking the deep tunneling construction in Dingji coal mine of Huainan mine area as the research subject, this thesis aims to investigate the anchoring effect of zonal disintegration in the wall rock of the deep tunnel through theoretic analysis and numerical software analysis of indoor geo-mechanical model test designed by the author. This research is innovative in the following aspects:(1) Similar material for iron crystal sand developed by Shandong University is used as raw material and processed with certain technical improvements to produce the similar material used in this test. High geo-stress true3D loading model test system is adopted to implement the model test for zonal disintegration in the wall rock of the deep tunnel. Comparative analyses are made between tests with and without anchor around the chambers, with the different damage degrees analyzed to demonstrate the reinforcing effect of anchor rod upon the zonal disintegration phenomenon. Also, the compression-tension alternation phenomena in rock bolt is got, which reflects that there exists the trend of forming zonal disintegration in deep rock mass.(2) The forming criteria of zonal disintegration are established based on the energy balance theory:the wall rocks applied with rock bolt can be equivalent to those with higher parameters first, the strain energy released through excavation and unloading is regarded as the energy resources of surrounding rocks damage, and the releasable strain energy was computed. Then, Take it to compare with the energy dissipatation during the formation of the circle fracture, the energy criteria of zonal disintegration is got.(3) The calculation model based on zonal disintegration of wall rocks in deep tunnels, which is programmed using FISH language within the FLAC[3D] System, performed numerical simulations of the model tests in this research, both with and without rock bolts. The fracture shape and fracture zones of zonal disintegration got from simulation are fit with the zonal disintegration phenomenon observed in test. To simulate the anchor partition rupture phenomenon cavern zonal disintegration phenomenon is not generated.