According to field observation and theoretical analysis, the failure of the 1523103 reserved roadway is mainly affected by the lateral support pressure, rock mass strength, and support mode. With the mining of the 152309 working face, the lateral pressure of coal pillars on both sides of the reserved roadway increases, and since the lithology of the two sides and the floor of the roadway is weak, the reserved roadway experiences spalling and floor heave. Through numerical simulation, the distribution law of surrounding rock stress and the displacement of surrounding rock are obtained after the roof cutting and pressure relief of the reserved roadway with hard roof. According to the cause of surrounding rock failure of a reserved roadway, the combined control technology of roof cutting and pressure relief, grouting anchor cable support, and bolt support is put forward. After cutting the roof and releasing the pressure on the working face, the lateral support pressure of the two sides of the roadway is significantly reduced, the deformation of the two sides of the roadway is small, the maximum shrinkage rate of the section is reduced from 70% to 11%, and the deformation of the surrounding rock of the 1523103 reserved roadway is effectively controlled. The successful control of the surrounding rock in the 1523103 tunnel reduces the number of coal pillars to be installed, improves the coal extraction rate, and is conducive to the sustainable utilization of limited natural resources and the sustainable development of the coal industry.

A fault is a common geological structure encountered in underground coal mining. Interactions between the discontinuous structure of a fault and mining activities are the key factors in controlling the rock bursts induced by the fault. It is of great importance to study the rock burst mechanism of an extra-thick coal seam under the combined influence of reverse faults and coal mining for the prediction and prevention of rock burst. In this study, we establish a sliding dynamics model of rock mass in a fault zone and analyze the mechanical distribution of fault-induced rock bursts under the combined action of mining disturbances. Additionally, we utilize theoretical calculation and a 3D numerical simulation method to clarify the rockburst mechanism in an extra-thick coal seam controlled by a thrust fault under mining disturbance and a fault. The results showed that the distribution range of the shear stress increment in the fault footwall was larger than that in the hanging wall, revealing a skewed distribution. The fault dip angle and mining thickness exhibit significant influence on the structure around the fault. With increases in the dip angle of the fault and mining thickness, the maximum vertical stress and peak stress first increase and then decrease. A position 80 m away from the fault is the dividing line between the fault-non-affected area and the fault-affected area. The 13,200 working face of the Gengcun coal mine is used as a case study to study the influence of mining disturbances on microseismic events. The results of this study are in good agreement with the theoretical calculations and numerical simulation results.

In order to study the physical and mechanical properties of sandstone under high-temperature water-cooling cycling conditions, an RMT-150B electrohydraulic servo rock testing system and a DS-5 acoustic emission detection and analysis system were used to conduct uniaxial compression acoustic emission tests on sandstone after high-temperature water-cooling cycles. The deformation, strength, and acoustic emission characteristics of sandstone were analyzed under different temperatures and cycle times. The results show that the high-temperature water-cooling effect caused changes in the physical properties of sandstone. The volumetric expansion rate of the rock samples first decreased, then increased in temperature, and the strength first increased, then decreased, whereas the number of cycles had less of an impact on the physical properties. At 200 °C, with increased cycle number, the elastic modulus increased by 20.1%, and the compressive strength increased from 63.9 MPa to 71.46 MPa. At 300–600 °C, the elastic modulus and compressive strength of sandstone gradually decreased with increases in the temperature and cycle number, with reductions of 6.04%, 7.24%, 28.7%, 35.57%, 17.6%, 18.2%, 20.4%, and 60.5%, respectively. With increased temperature and cycle times, the acoustic emission ringing counts increased, ringing counts and cumulative energy appeared earlier, the rock samples entered elastic deformation earlier, the yield stage length increased, and the samples showed a tendency to transition from brittle to ductile damage.

To study the effects of deep rock drilling pressure relief under high stress conditions in enhanced geothermal systems, two kinds of drilling pressure relief experiments were conducted on sandstone—the staged drilling of pressure relief holes before peak stress and one-time drilling. Pressure relief experiments were carried out on sandstone with two borehole methods of the stage-by-stage drilling and one-time drilling of pressure relief boreholes ahead of the experiments. FLAC3D was used to analyze the plastic zone evolution during drilling and the relationship between stress and plastic zone volume. The results reveal the pre-peak stress change characteristics and pressure relief features of non-prefabricated boreholes under high stress. The experiments show that the staged drilling of pressurized samples involves stages of rapid and gradual decreases in stress, with total relief amplitudes increasing but single-borehole relief decreasing with more holes. Under the same conditions, staged drilling has better relief effects and results in greater energy dissipation, indicating that incremental pre-peak pressure relief is beneficial for reducing the surrounding rock’s impact tendency and improving stability. The research results can provide good guidance and reference for the long-term stability analysis of borehole-containing rock and rock burst hazard control.

The control difficulty of whole coal cavern groups is greatly increased due to the characteristics of soft rock with low strength, large sections, and the mutual influence of crossed cavern groups. The large section gas storage cavern group is taken as the research background. In this paper, the equivalent circle method is used to solve the loose circle of a rectangular roadway, and numerical calculation is used to obtain the deformation and stress distribution laws of the surrounding rock under the excavation conditions of large section whole coal cavern groups (WCCG). The deformation and failure mechanisms of the surrounding rock are revealed under the linkage impact between large section whole coal cavern groups. The stratified reinforcement ring concept of “long cable-bolt-grouting” (LBG) was proposed for the stability control of surrounding rock in the WCCG. On the roof of whole coal cavern groups, the supporting configuration of a high-strength bolt with a high pre-tightening force and the high-strength anchor with a high pre-tightening force were determined. On the two sides and floor of the WCCG, the grouting scheme was determined. These two supporting configurations in both the roof and sidewalls were applied to the large section gas storage cavern group. The results show that the surrounding rock presents asymmetric deformation and failure characteristics due to the large excavation area and complex structure. Tensile failure and mixed tensile-shear failure mainly occur in the shallow part of the surrounding rock, while shear failure mainly occurs in the deep part of the surrounding rock. The roof displacement curves show a symmetric distribution and saddle distribution in the low- and high-negative pressure caverns, respectively. The maximum displacements are on the left and right sides of the cavern roof. The range of the loose rings is 3.34 m and 2.54 m, respectively, on the roof and the two ribs. The stratified reinforcement ring support technology of LBG can effectively reduce the failure depth of surrounding rock, and the surrounding rock is in a stable state. The study can provide a theoretical basis for the layout of large section cavern groups and the stability control of surrounding rock.

Research on the deformation characteristics and failure modes of buried pipelines under local suspension conditions caused by groundwater loss in coal mining subsidence areas is conducive to grasping the failure evolution law of pipelines and providing technical support for the precise maintenance of gathering and transportation projects and the coordinated mining of gas and coal resources. First, a test system for monitoring the deformation of pipelines under loading was designed, which mainly includes pipeline load application devices, end fixing and stress monitoring devices, pipeline end brackets, and stress–strain monitoring devices. Then, a typical geological hazard faced by oil and gas pipelines in the gas–coal overlap area—local suspension—was used as the engineering background to simulate the field conditions of a 48 mm diameter gas pipeline with a localized uniform load. At the same time, deformation, top–bottom strain, end forces, and damage patterns of the pipeline were monitored and analyzed. The results show that the strain at the top and bottom of the pipeline increased as the load increased. In this case, the top was under pressure, and the bottom was under tension, and the conditions at the top and bottom were opposite.. For the same load, the strain tended to increase gradually from the end to the middle of the pipeline, and at the top, it increased significantly more than at the bottom. The tensile force carried by the end of the pipeline increased as the applied load increased, and the two were positively correlated by a quadratic function. The overall deformation of the pipeline evolved from a flat-bottom shape to a funnel and then to a triangular shape as the uniform load increased. In addition, plastic damage occurred when the pipeline deformed into a triangular shape. The results of the investigation clarify for the first time the mathematical relationship between local loads and ultimate forces on pipelines and analyze the evolution of pipeline failure, providing a reference for pipeline field maintenance. Based on this, the maximum deformation of and the most vulnerable position in natural gas pipelines passing through a mining subsidence area can be preliminarily judged, and then the corresponding remedial and protection measures can be taken, which has a certain guiding role for the protection of natural gas pipelines.