Study on creep deformation and energy development of underground surrounding rock under four-dimensional support

There is an urgent need to develop optimal solutions for deformation control of deep high-stress roadways, one of the critical problems in underground engineering. The previously proposed four-dimensional support (hereinafter 4D support), as a new support technology, can set the roadway surrounding rock under three-dimensional pressure in the new balanced structure, and prevent instability of surrounding rock in underground engineering. However, the influence of roadway depth and creep deformation on the surrounding rock supported by 4D support is still unknown. This study investigated the influence of roadway depth and creep deformation time on the instability of surrounding rock by analyzing the energy development. The elastic strain energy was analyzed using the program redeveloped in FLAC^3D. The numerical simulation results indicate that the combined support mode of 4D roof supports and conventional side supports is highly applicable to the stability control of surrounding rock with a roadway depth exceeding 520 m. With the increase of roadway depth, 4D support can effectively restrain the area and depth of plastic deformation in the surrounding rock. Further, 4D support limits the accumulation range and rate of elastic strain energy as the creep deformation time increases. 4D support can effectively reduce the plastic deformation of roadway surrounding rock and maintain the stability for a long deformation period of 6 months. As confirmed by in situ monitoring results, 4D support is more effective for the long-term stability control of surrounding rock than conventional support.