Abstract: In order to accurately identify the extent of the loosening circle of the water-rich soft rock roadway at the -550 m level of the Zhongjiu Iron Mine，and to guide the support parameter design of unloading chamber，the following work has been carried out.A loose ring survey was conducted at the -550 m level using sonic and borehole imaging methods.Three sets of sonic tests and two sets of borehole imaging tests were designed and analyzed to determine the extent of the loosening ring.A simulation study on support scheme of unloading chamber was carried out based on it.The results show that the joint testing method is more effective in carrying out the test of the loose circle range of the roadway.The ultrasonic wave velocity and structural surface morphology information of different test hole depths were obtained by the sonic method and the borehole imaging method，respectively.The comprehensive analysis can accu ⁃ rately detect the loose circle range of the roadway.The loosening circle of the -550 m level roadway of Zhongjiu Iron Mine ranges from 2.2 to 5.2 m，accounting for 0.6 to 1.5 times of the roadway span.A con⁃ trol scheme for chamber deformation was proposed，and its effectiveness was verified by numerical simula ⁃ tion .

Key words: loosening circle of surrounding rock, sonic method, borehole imaging method, union test methods, numerical simulation