Research progress of deep shaft construction mechanics

With the increasing depletion of shallow coal resources,China’s coal mining is developing in the direc-tion of deepening and large-scale development.The annual production capacity of newly built and expanded large vertical shafts has reached 10 million tons,and the maximum mining depth has reached 1 500 m.The high stress and “anisotropy”(including rock mass,structure,stress,etc.) complex geomechanical environment,in which a thousand meter deep shaft was built,caused collapse,rock burst and impact in the surrounding rock of the shaft and the main roadway at the bottom of the shaft during shaft construction.Large deformation disasters such as ground pressure have seriously affected the safe and efficient construction of deep mines.Supported by the key special project “the basic theory and key technology of deep coal mine construction and upgrading” within the national key research and development plan “Deep Ground Resources Exploration and Mining”,a deep non-uniform pressure shaft construction model was proposed to deal with non-uniform surrounding rock pressure with non-uniform support.The typical stratum structure of deep shaft in coal measure strata was classified,and the mechanical model of vertical shaft under different stress conditions in deep mine was established.A series of multi field and multi scale rock mechanics experiments under simulated deep environment were carried out,and the large deformation mechanics characteristics during the interaction between the anisotropy of the deep shaft-building rock mass and the deep environment were explored,and the mechanical mechanism of large deformation of rock mass in the deep complex geological environment was revealed.A new NPR bolt/cable material suitable for the large deformation control of deep shaft was developed,a series of drawing mechanics experiments was conducted to scientifically demonstrate its superiority,and a complete set of NPR bolt/cable based support technology was obtained.A study on the construction of the N00 mine without coal pillars and self contained roads was carried out.Based on the theory of “cut top and broken arm beams”,a mining engineering model with invariable mining damage was established.