关键词: 采空区, 采动影响, 保留巷道, 塑性区, 围岩控制

Abstract: In order to study the deformation and failure laws and stability control of surrounding rock under the influence of repeated mining in double roadway layout working face, numerical simulation, theoretical analysis and field observation were conducted to analyze the influence of double roadway spacing on the spatial distribution characteristics and deviatoric stress of plastic zone under repeated mining. The induced expansion mechanism of secondary mining on plastic zone of retaining roadway was revealed, and the second expansion inhibition method of rock plastic zone was proposed. The results show that the plastic zone of surrounding rock in repeated mining roadway can be divided into six areas in the axial direction of roadway, the larger the distance between two roadways is, the smaller the damage depth of plastic zone is, and its shape changes from asymmetric distribution to symmetric distribution. The main reason is that the stress rotation degree and the peak value of deviator stress caused by the increase of distance between two roadways are low. One mining hysteresis affects the longest maintenance distances and cycles in the stability zone and it is the basis of superimposed expansion of plastic zone in secondary mining, and it is the key control area of surrounding rock stability in repeated mining roadway. On the basis of this, the purpose of improving the stress environment and adjusting the failure state of surrounding rock of roadway can be reached by adjusting the spatial position of roadway. Besides, the control method and control technology system of regional reinforcement and support were established. The field measurement results show that the technical system can achieve the goal of roadway safety and stability, and the effect is satisfactory.

Key words: goaf, mining influence, gob-side entry, plastic zone, surrounding rock control