Primary rupture law of main roof in long-wall face based on principal bending moment

In order to accurately understand the primary rupture law of main roof in long-wall face, the principal bending moment was visualized with the aid of MATLAB software, the rupture direction of each region of the main roof was theoretically analyzed, the rupture sequence of each region of the main roof was explored, and the rupture law of the main roof was verified based on the model experiment. The research results show that: (1) The point where the absolute value of the control bending moment in the long-side region is the largest is the midpoint of the long side. The absolute value of the control bending moment in the length direction of the working face is greater than that in other directions. (2) The point with the maximum control bending moment in the middle region is the midpoint of the middle. The control bending moments in the length direction of the working face are greater than those in other directions. (3) The point where the absolute value of the control bending moment in the short-side region is the largest is the midpoint of the short side. The absolute value of the control bending moment in the propulsion direction of the working face is greater than that in other directions. (4) Under various influencing factors, the absolute value of the control bending moment at the midpoint of the long side is the largest, and the absolute value of the control bending moment at the midpoint of the short side is the smallest. The main roof breaks first from the midpoint of the long side. As the coal mining face advances, the midpoint of the middle and the midpoint of the short side break successively, eventually forming an O-X type rupture morphology. The revelation of the primary rupture law of main roof in long-wall face is conducive to carrying out the support design of the working face, improving the management level of mine pressure, and ensuring the safe production of the coal mining face.