关键词: 应力集中, 补强支护, 围岩控制, 数值模拟, 现场监测

Abstract: The underlying mined-out area will form a significant stress concentration zone in the overlying rock layer，adversely affecting the stability of the upper roadway. Taking the bottom extraction roadway of a certain mine in Anhui Province as the engineering background，the FLAC3D numerical simula⁃ tion method was adopted to conduct a study on the stress concentration pattern of the underlying mined-out area on the bottom extraction roadway layer. In response to the stress distribution when the roadway passes through the top and bottom plates of the stress concentration zone，a secondary anchor bolt (cable) rein⁃ forcement support scheme was proposed，and the monitoring and verification of the roadway surrounding rock fragmentation and surface deformation were carried out. The results show that as the mining range of the underlying working face increases，the range and amplitude of the upper stress concentration zone con⁃ tinuously increase. After the complete mining of the working face，a stress concentration zone with a stress concentration coefficient of approximately 3.5 is generated in the overlying roadway layer. The roadway bot⁃ tom plate bears the concentrated stress generated by the underlying mined-out area，while the top sur⁃ rounding rock shows a stress reduction zone. The complex stress distribution is very likely to cause local damage to the roadway. The field monitoring results indicate that after using the secondary anchor bolt (ca⁃ble) reinforcement support，the distribution density of the roadway surrounding rock fractures is low，and the final displacement of the top and bottom plates and both sides is 31 and 23 mm respectively，without any accidents such as roof leakage or roof collapse. The proposed secondary anchor bolt (cable) reinforce⁃ ment support method for the research on the support technology of deep well roadways affected by the stress concentration of the underlying mined-out area provides design basis and application reference for the roadway crossing the stress concentration zone.

Key words: stress concentration, reinforcement support, surrounding rock control, numerical simula? tion, field monitoring