Study on layout optimization of deep super-large section sorting chamber group

In order to meet the requirements of underground sorting and in-situ filling，multiple chambers are usually densely arranged underground. The chamber group layout has a significant impact on the control of surrounding rocks，which is an important content of the chamber group design. Against the background of the -800 m level coal gangue separation chamber group at Xinjulong Coal Mine，theoretical analysis，numerical simulation and field monitoring methods are used to discuss the influence factors of surrounding rock stability. Then the FLAC3D numerical model is built to get the deformation and failure law with different layout. The results show that the mutual influence of surrounding rocks gradually decreases with the spacing increases. The optimal spacing is about 15 m for the same level layout，and about 18 m for the staggered layout. When the chambers are same level layout with the spacing of 15 m，the stress concentration area of surrounding rock is mainly located at the intersection of chambers with the peak stress 35 MPa，the largest deformation 43 mm and the plastic zone width 5 m，and there are elastic bearing rock pillars about 5 m square between the chambers. In the field practices，four chambers are arranged with a “well-shaped” pattern，and the distances range from 15-89 m. The practices show that the deformation of chamber group is mainly concentrated in the excavation stage，and the largest deformation in the middle is about 26 mm. This research can provide references for the layout design and parameter optimization of deep-buried chamber group.