In order to study the influencing factors of floor deformation and floor heave mechanisms of deep mining roadways, this paper takes the deep dynamic pressure mining roadway of a mine as the engineering background and adopts a research method combining theoretical analyses, numerical simulations and field observations to study the influence of various factors on floor deformation and floor heave mechanisms. It is determined that the influencing factors on floor heave are a large buried depth, a long duration of dynamic pressure, unique characteristics of the surrounding rock and an insufficient support strength. A bearing mechanics model of the roadway floor beam is established, and it is determined that the displacement of the roadway floor is negatively correlated with the elastic modulus and floor thickness and positively correlated with the buried depth of roadway, the roadway width and the width of fracture zone. A numerical simulation method is used to study the influence of the original geological conditions, strengthening the elastic modulus of floor, strengthening the strength of the side wall rock and increasing the thickness of the floor rock on the displacement of the roadway floor. It is determined that increasing the thickness of floor rock controls the floor heave the most, followed by strengthening the elastic modulus of the floor rock and then strengthening the strength of the side walls. The results of the numerical simulation agree well with those of the theoretical analysis. After the control method of “bottom lifting + bottom angle bolt + floor bolt ” is adopted on site to treat the floor heave, the floor heave volume of the roadway is small during the service period of the 303 working face return air roadway, which meets the application requirements of the roadway. Meanwhile, the theoretical analysis and numerical simulation results are indirectly verified.

The macroscopic characteristics of the fractured space and the microscopic pore features are critical factors determining the effectiveness of gangue slurry backfilling. To identify the key areas for slurry backfilling, a combination of theoretical analysis, simulation experiments, and on-site industrial trials was used to reveal the movement laws of backfilling space overlying the fractured zone. The distribution characteristics of voids available for slurry backfilling within the fractured space were explored, and the interaction between gangue slurry and goaf voids was clarified. A formula for calculating the void ratio in the caved zone was derived, and a model for the distribution of voids in the slurry backfilling space was established. This model identified the main areas where slurry backfilling should be focused, namely the overlapping space between the free accumulation zone and the load-influenced zone. Experimental results demonstrated that the porosity of the collapsed rock mass within the goaf follows a negative logarithmic function along both the dip and strike directions, which was consistent with the theoretical calculations. Through in-situ grouting backfilling experiments on the ground, the feasibility of gangue slurry backfilling in the goaf was verified, and the process of interaction between gangue slurry and goaf voids was elaborated. This process generally involves three stages: initial flow, vertical upwelling, and horizontal diffusion, all of which are closely interconnected. Practical engineering applications of gangue slurry backfilling were carried out in the free accumulation zone and the load-influenced zone at the Huangling No. 2 coal mine. The successful validation of underground gangue slurry backfilling technology demonstrated its feasibility and the correctness of the theoretical approach. This research provides new evidence for environmentally friendly disposal of gangue materials.

Coal gangue slurry filling is an important technical means for harmless and large-scale disposal of gangue under low-interference conditions, and is one of the most important ways to achieve green mining, which is in line with the national concept of green development. This paper systematically expounds the technical background and scientific connotations of the birth of slurry filling, clarifies the key technology and process principles of slurry filling, and constructs the lag distance and optimization method of slurry filling based on the bulking coefficient. In order to explore the distribution law of the bulking coefficient of the overburden broken zone in the mining process, UDEC numerical simulation and similar simulations were used to analyze the movement law of a coal seam roof and the distribution characteristics of the bulking coefficient. The results show that with the evolution of the spatial structure of the overlying strata of the goaf, the subsidence of the coal seam roof decreases from the bottom to the top, and finally becomes stable. In the advancing direction of the working face, the bulking coefficient decreases continuously, and shows certain zoning characteristics. With the mining, it moves forward periodically with dynamic changes. In the strike direction, it can be divided into three areas: the natural accumulation area, the load-affected area and the gradual compaction area. Finally, the lag distance of slurry filling is determined to be 60 m, and the effect of adjacent grouting filling is good in the field test.

The wet carbonation of coal gangue-based backfilling slurry (CGBS) is considered to be an effective method for the resource utilization of coal gangue solid waste and CO₂ sequestration, but CO₂ sequestration has a negative impact on the rheological properties of CGBS. This investigation explores the effect of carbonization pressure on the rheological properties and CO₂ sequestration properties of CGBS by using a carbonization reactor, a rheometer, X-ray diffraction, a nitrogen adsorption–desorption instrument, a scanning electron microscope and other testing methods. The results show that increasing the carbonization pressure can increase the CO₂ sequestration capacity of CGBS, and the carbonization products produced make the pores of CGBS smaller and the structure more compact; however, increasing the carbonization pressure will reduce the rheological properties of the slurry, and the optimal carbonization pressure is 0.7 MPa. At this time, the yield stress, plastic viscosity and hysteresis loop area of CGBS are 171.66 Pa, 0.0998 Pa·s and 1376 Pa/s, respectively. However, when the carbonization pressure is further increased, the CO₂ sequestration capacity tends to remain unchanged. This is mainly because the carbonization pressure causes the carbonization reaction to intensify, forming a calcified layer on the particle surface, which hinders the penetration of CO₂ into the particles. This study is of great significance for improving the utilization rate of gangue solid waste and CO₂ sequestration.

Cemented backfill coal mining technology is gradually becoming a key technology for green mining of coal resources. And cemented backfill materials generally have congenital defects such as poor crack resistance, poor durability, and high brittleness, which restrict the promotion and application of cemented backfill coal mining technology. Due to the complex stress environment of in situ stress, mining stress, water pressure, and gas pressure, cemented backfill materials need to have good mechanical properties, and glass fiber is usually used to mix into cemented backfill materials to improve its performance, but there are many problems including complex testing process, high cost, and long time-consuming in the study of mechanical properties of glass fiber-modified cemented backfill materials (GFCBM) by laboratory tests. Consequently, this study proposed and compared four artificial intelligence models to forecast the tensile strength of GFCBM. Firstly, the laboratory tests of tensile properties of GFCBM under different influence factors were implemented to supply the prediction model with dataset. The input variables are aeolian sand content, cement content, glass fiber length, and glass fiber content, and the output variable is the tensile strength of GFCBM. The correlation coefficient (), mean absolute error (MAE), and root mean square error (RMSE) are selected to assess the estimated performance of the hybrid intelligent model. The results indicate that the four hybrid artificial intelligence models show a latent capacity for forecasting the tensile strength of GFCBM, and according to the order from high to low, the prediction ability of the four prediction models is as follows: ABC-SVM, GA-SVM, SSA-SVM, and DE-SVM, and the corresponding values are 0.9555, 0.9539, 0.9413, and 0.9359, respectively. The research findings are beneficial to promote the application of cemented backfill coal mining technology.

Based on the S1201-2 large height mining in the 2–2 coal seam of Ningtiaota colliery with on-site microseismic measurement, physical simulation and theoretical analysis methods, this paper explores the rule of roof movement in thick coal seams with roof cutting and non-pillar (hereinafter referred to as RCN-P) mining, so as to obtain scientific and effective theoretical basis for entry support and to summarize the regional structural characteristics and dynamic periodic fracture characteristics. As can be seen from microseismic events, the entry roof is featured by "two zones and one line" along the horizontal direction, namely, the crack generation area, the roof movement area. Additionally, and the obvious lateral breaking of the entry roof on the coal wall is a typical feature of the thick coal seam with RCN-P mining. The roof is vertically divided into "three zones", the crack generation area, the roof movement area and the crack development area. The roof cutting activity mainly affects the overburden activity within the basic roof height range, which is also the roof movement area. In addition, the distribution frequency and the intensity of microseismic events indicate the roof periodic breaking characteristics. The "breaking pressure relief,” “advanced crack development,” and “the limit breaking state” of roof breaking corresponds to the initial, middle, and final stage of breaking in the periodic weighting process, respectively. Compared with the normal mining, the RCN-P mining reduces the periodic weighting length and increases the pressure strength. As is shown in the physical simulation experiment, the basic roof and the cutting control layer in the "regional structural characteristics" constitute the “large” and “small” structures with RCN-P mining. The basic roof key layer is the core to control the stability of the strata, and the breaking process from the cantilever beam to the short masonry beam of the roof-cutting control layer is the main cause of the entry stress. Correspondingly, the basic structure model of “short masonry-hinged” roof was proposed and the calculation method of support was established for the entry with RCN-P mining in thick coal seam, providing a research foundation for scientific and effective rock formation control.