After the coal mine disaster, the collapse accumulation blocked the roadway and interrupted the rescue route, which seriously affected the development of the rescue work. Taking the rescue route of post-disaster collapse accumulation body in fault fracture zone as the background, based on clarifying the geological characteristics of fault fracture zone and the shape of accumulation body for the first time, the size formula of roadway caving area, the formula of accumulation body coverage, the calculation formula of accumulation body height is derived, and the deformation characteristics and debris movement mode of accumulation body are discussed. It is found that the fault fractured zone can be divided into three types: fragment type, crack type, and symbiotic type; The harder the rock fragment is, the more dispersed the particle size is; The number of contact points of tight accumulation body is more than that of loose accumulation body; The size of the caving area and the height of accumulation body are related to roadway height, width, lateral stress coefficient, and similar internal friction angle. The coverage of the accumulation body is related to the roadway height, the length of the fault fracture zone, the accumulation angle of the front area, and the accumulation angle of the back area. The field measurement results show that the calculation formulas of roadway goaf size, accumulation body coverage and accumulation body height accord with the field practice, and the coincidence degree is high; and the deformation of the accumulation body can be divided into load deformation and creep deformation. There are three ways of block adjustment: lateral movement adjustment, longitudinal movement adjustment, and self-rotation adjustment.

In the coal-rock system, the interlayer weak zone between coal and rock layers is the primary area of fracture distribution. These fractures penetrate the coal and rock layers, seriously impacting the mechanical properties and engineering stability of the coal-rock system. To investigate the impact of penetrating fractures on the mechanical properties of the coal-rock system, axial loading tests were conducted on prefabricated coal-rock composite bodies with five different fracture lengths and angles. The findings indicate that: 1) As the fracture length increases, the compressive strength, elastic modulus, peak energy, and impact energy index decrease linearly. Regarding the fracture angle, the compressive strength, elastic modulus, peak energy, and impact energy index initially decrease and then increase. 2) The destructive acoustic emission tests of the samples exhibit three stages: a quiet period, an active period, and an intense period, respectively. With increasing fracture length, the cumulative energy of acoustic emission initially increases and then decreases. Similarly, with increasing fracture angle, both peak energy and cumulative energy of acoustic emission first increase and then decrease. 3) The length and angle of fracture have a certain influence on the wing crack, secondary inclined crack, secondary coplanar crack, oblique crack, secondary derivative crack, wing crack derivative crack, far field crack and spalling phenomenon. 4) As fracture length increases, the cohesion and internal friction gradually decrease, while an increase in fracture angle leads to a decrease followed by an increase in cohesion and internal friction. 5) The Drucker-Prager strength criterion considering fracture length and angle was developed, and rationality verification indicated a sample error within a reasonable range of 1.367% to 5.055%. 6) Based on the dissipative structure theory, the study analyzed the mechanism of instability failure in the coal-rock combined body. The failure process of the combined body involved four main stages: quasi-steady state, metastable state, instability, and establishment of a new steady state. An energy migration model for the fractured coal-rock combined body was developed, and the energy migration pattern during the instability and failure of the fractured coal-rock combined body was analyzed. The ends of the fracture were identified as the primary areas of energy accumulation. Destruction of the coal component’s fracture end led to the migration of energy towards the fracture end of the rock component, resulting in the release of energy through rock component destruction or deformation. These research findings offer valuable insights for investigating the mechanical characteristics of deep coal and rock, as well as understanding the mechanisms behind dynamic coal and rock disasters.