Integrity detection and control method for lower layered 'mixed roof' of thick coal seam

The invention discloses an integrity detection and control method for a lower layered 'mixed roof' of a thick coal seam. The method comprises the steps of accurately detecting the integrity of the lower layered 'mixed roof' of the thick coal seam by adopting a geographic, physical and chemical comprehensive detection method of high-density electrical method, a radon gas detection method and an electromagnetic wave CT method according to the deformation and failure characteristics of a surrounding rock in an old goaf after upper slice mining of the thick coal seam; determining the specific position and distribution range of a local fracture zone in the lower layered 'mixed roof' of the thick coal seam; optimizing and designing a grouting reinforcement scheme of the local fracture zone on this basis; determining a reasonable grouting reinforcement material; and carrying out pre-grouting and delayed curing grouting on the local fracture zone in the lower layered 'mixed roof' of the thick coal seam. Compared with the prior art, the integrity detection and control method is high in operability, high in efficiency and high in pertinence, and has wide practicability and extendibility under the similar coal seam roof condition.