In order to study the changing rules of displacement filed and stress field of overlying strata on isolated pillar with filling mining method, a self-designed model of isolated pillar with an equivalent mining height and a monitoring system of stress is employed to study the progressive failure of overlying strata and the changing rules of induced displacement and stress, as the equivalent mining height increases. The findings from the trial tests show the following: (1) When the equivalent mining height is small, the overlying strata on the isolated coal pillar only bend and subside, but the overlying strata located on the goafs of two sides remain stable. (2) As the equivalent mining height increases, the degree of stress concentration on section coal pillar will rise and produce plastic failure in the first place near large caving goaf. The strata can subside between isolated working face and adjacent large caving goaf. (3) As the equivalent mining height increases further, new cracks in the roof of isolated working face will unite the cracks of carving goaf on two sides in horizontal direction, leading to a significant rise of the height of cracks. Three goafs will evolve into a large carving goaf, and the vertical cracks on the outer side of the carving goaf intersect with one another to form “fracture band”. The research acquires the key points for prevention in mining the isolated coal pillar with filling method and provides guidelines to implement this technique and to prevent rock burst.

In deep coalmines, longwall panels are subject to high static initial geostress andhigh dynamic stress caused by mining and tunnelling activities. Under the action of high static and dynamic stress, rockburst hazards are very likely to occur. To reduce rockburst risks, protective panels are commonly applied in deep coalmines. However, stress concentration in the protective coal panel often causes rockburst hazards in the gateway of the next longwall panel pending mining. To reduce such type of rockburst, this study firstly proposes a mathematic model to analyse the overall static stress distribution in the protective panel based on the mining practice in Longyun coalmine, Shandong Province, China. To evaluate the stress concentration caused by geological defects in the protective panel, a new rockburst evaluation index is proposed based on the computed tomography (CT) method. Finally, the extent of dynamic stress evolution caused by different working face advancing velocities is determined by microseismic monitoring. Results show that the areas with higher rockburst evaluation indexes are highly associated with the areas with large-energy microseismic events, indicating that the static stress concentration can be accurately identified by the CT method. A medium advancing velocity (4.0 m/s) is recommend during mining the longwall panel, which can ensure mining safety and improve mining productivity simultaneously. The integrated microseismic and CT monitoring methods can be used in other underground projects to guarantee construction safety and productivity.

With the development of faults in many coalfields, many large faults will form a relatively independent area, forming regional tectonic stress concentration. Under the influence of mining, it is easy to induce fault activation, produce mine tremor, and then induce rock burst. Through field investigation, theoretical analysis, numerical simulation, and engineering verification, the overburden movement model of No. 3504 working face square and fault activation in Liangbaosi Coal Mine was established. The stress variation and energy release law of working face advance and fault area were analyzed, and the mechanism of rock burst under the coupling action of working face square and regional tectonic stress was revealed. The results show that the regional stress adjustment and fault activation are caused by the large‐scale overall movement of overburden during the working face square, and there is a peak value of elastic energy release during the fault activation, which is easy to produce large energy mine earthquake. The energy level of the daily maximum energy event is higher than that of the initial mining stage in the square period, and the location of on‐site large energy microseismic event is basically consistent with the predicted fault strike. The study provides a theoretical basis for the prevention and control of rock burst during the working face square under the condition of regional tectonic stress.

Aiming at the calculation problem of bearing pressure of typical overlying strata structure, in this paper, mechanical calculation, field monitoring and other methods are used to study the influence range of abutment pressure. Recently, many major rock burst accidents in working surface show that with the increase of mining depth and the change of overlying strata structure, the abutment pressure distribution has become one of the problems of safe mining. The influence range, distribution of high stress area and peak position of working surface support pressure need to be solved urgently; and through theoretical analysis, this paper reveals (whole rock single-layer structure, whole rock layered structure, whole rock single-layer structure—without arch in soil layer, whole rock layered structure—without arch in soil layer, whole rock single-layer structure—with soil arching, whole rock layered structure—with soil arching) the stress transfer mode, transfer size, and arching conditions of overlying strata in different areas. The mechanical system of abutment pressure calculation for typical overburden structure is established, which provides theoretical basis for mine optimization design scheme, mining sequence, and limited personnel distance.

This study takes the rockburst risk assessment of a section coal pillar in a high-impact rockburst mine in Shandong Province as the engineering background. Through field monitoring, theoretical analysis, numerical simulation, and other research means, it investigates the impact risk after the section coal pillar is intersected by multiple faults. The main conclusions are as follows: A mechanical calculation model was established to analyze the stress distribution within the irregular coal pillar region. The analysis indicates that when the coal pillar width is 106 m, the stress within the pillar is approximately 42 MPa; when the width is 158 m, the stress is about 33 MPa. In this study, the stress field distribution in the coal pillar area was analyzed at various stages: after the extraction of the 1306 working face, and as the 1310 working face advanced to 50 m, 100 m, 190 m, 250 m, 380 m, 593 m, and 850 m. The results revealed the following dynamic process: Before mining the 1310 face, high-stress zones were primarily concentrated near the fault and the acute-angle area of the 1306 goaf. After the 1310 face advanced 50 m, the high-stress zone began to expand toward the front of the 1310 working face, while the high-impact risk zone remained predominantly within the acute-angle region between the 1306 goaf and the fault. When the 1310 working face advanced by 100 m, high‑stress concentration zones were mainly distributed in two areas: one around the 1310 working face, and the other primarily in the acute‑angle intersection region between the 1306 goaf and the fault. At an advance of 190 m, a “square‑off” effect appeared in the 1310 working face, with high stresses concentrated mainly in the acute‑angle intersection zones of both the 1306 goaf and the 1310 working face with the fault. After the 1310 working face passed through the “square-off” effect zone and before its expansion, high stress was mainly concentrated in the acute-angle intersection region between the 1310 working face and the fault. Following the expansion of the 1310 working face, the coal pillar width decreased from 158 to 106 m. The reduction in pillar width led to a significant increase in overall stress within this section, as confirmed by both theoretical calculations and simulations, indicating a risk of full‑scale impact. Research of this type provides a valuable reference for the safe mining of working faces intersected by multiple faults in deep coal mines with high rockburst risk.