Deformation Characteristics and Grouting Control Technology of Reused Roadway in a Fully Mechanized Coalface with Large Mining Height

Reused roadways are increasingly adopted in fully mechanized coalfaces with large mining heights because of the ventilation and gas drainage problems. However, the forced mechanism and grouting control technology of the reused roadway was seldom studied. Hence, in this paper, field monitoring and numerical simulation were undertaken to investigate the distribution of stress and deformation of the reused roadway, and the reasonable grouting opportunities and technological parameters were determined accordingly. Engineering application of grouting control technology with self-developed inorganic double-fluid grouting materials was conducted. The field monitoring and numerical simulation revealed that the reused roadway was significantly affected by the lateral abutment pressure during the first mining operation and by the leading abutment pressure during the second mining operation. It was characterized by lagging stable deformation during the first mining operation and ceaselessly increasing deformation during the second mining operation. The deformation range of the reused roadway during the first mining operation can be divided into three stages: initial deformation, violent deformation and plateaued deformation, while the deformation range can be divided into three distinct stages: initial deformation, slow deformation and violent deformation during the second mining operation. On the basis of the roadway deformation law, two grouting opportunities were confirmed. The first grouting opportunity was suggested in the front part of the plateaued deformation stage during the first mining. The second grouting opportunity was suggested in the slow deformation stage during the second mining. Field engineering applications showed that both the deformation range and value of the reused roadway were decreased obviously after grouting