Optimization of layout pattern of underground laboratory cavern groups with buried depth of 2400 m

Deep underground laboratory is the foundation of deep mining resources in the future. Jinping underground laboratory in China is the deepest underground laboratory in the world. The construction of No. 8 experimental cavern may involve the research of deep rock mechanics, so multiple caverns will be designed and excavated to carry out in-situ mechanics tests and principle exploration. However, the stability of underground laboratory is directly influenced by the layout pattern of cavern groups. Therefore, aiming at the excavation of the underground experimental caverns under high geostress, a 3D numerical model is established by FLAC. The influences of excavation of the subsequent caverns on the stability of surrounding rock of excavated caverns are compared, which include different spacings at the same side and different layouts at opposite sides, then the value of displacement is introduced to identify the influences of excavation on the caverns which are built. The result shows that the layout with the spacing of 8 m at the same side and the symmetry at opposite sides is optimal. They may guide the layout of underground cavern groups in Jinping’s No. 8 laboratory. Moreover, it can offer a reference for the layout of other similar underground projects.