Abstract: In order to solve the problem of stability control of super large section chamber caused by broken surrounding rock and high level stress,a broken chamber with a section size of 145.83 m2 in a copper mine in Serbia is taken as the re search object.From the perspective of coupling of support and deformation characteristics of surrounding rock and elastic-plas tic theory,a stability control technology of surrounding rock based on the principle of "asymptotic stress release-flexible yield overall bearing pressure" is proposed.Through FLAC3D numerical simulation,different excavation and support schemes are compared,and the excavation and support scheme of the chamber is determined by using the layered positive step construction method of the middle pilot tunnel and the combined support of "anchor net spray + anchor cable + primary steel-concrete". The results show that the stress release compensation space is formed by the small section pilot tunnel,and the maximum prin cipal stress in the plastic zone at the top of the chamber is 7.18 MPa lower than that of the upper layer.The synergistic effect of prestressed anchor bolt and anchor cable forms the suspension effect of shallow composite arch,which inhibits the expansion of fracture zone.The shotcrete and steel-concrete structure are applied in stages to achieve a smooth transition from flexible yielding to rigid bearing.After the combined support,the maximum vertical displacement of the roof surface of the chamber is reduced by 88.17%,the maximum lateral displacement of the side surface is reduced by 88.41%,the volume of the plastic zone is reduced by 39.17%,and the plastic zone of the chamber surface is no longer formed.The field application proves that the surrounding rock stability control technology can ensure the long-term stability of the crushing chamber,which provides a reference for the excavation and support of similar super-large section chambers.

Key words: broken surrounding rock,super-large section chamber,grading-control,combined support