Abstract: To improve the accuracy of identifying the surrounding-rock loosened zone in deep-buried roadways, the deep roadways were taken as the engineering background. Ground-penetrating radar testing, theoretical calculation, and FLAC–PFC continuum–discontinuum coupled simulation were employed to investigate the distribution characteristics of the loosened zone. The results show that the loosened-zone thickness measured by ground-penetrating radar in Grade III–IV surrounding rock ranges from 0.5 to 1.4 m, while no distinct boundary was identified in approximately 28.6 % of the tested areas. The loosened-zone thickness calculated using six theoretical equations ranges from 0.64 to 2.56 m. The coupled simulation yields a loosened-zone thickness of approximately 1.25 m. The failure is dominated by shear cracking, with the ratio of tensile cracks to shear cracks ranging from 0.15 to 0.20. When the stress release ratio increases from 95 % to 100 %, the total number of cracks rises from 5,451 to 9,479, representing an increase of approximately 74 %. Because the results obtained by different methods vary, the loosened-zone range should be comprehensively determined by combining field testing, theoretical estimation, and numerical simulation, and timely support confinement should be applied to control surrounding-rock failure.