In-situ stresses are significantly important for underground mining geotechnical design and coal seam gas management in underground coal mines. Aiming at regions with geological structures, this paper proposes an in-situ stress inversion method combining Rhino precise modeling and transverse isotropy theory, and tests it near the Guodishan fault. The results show that the application of Rhino precise modeling and transversely isotropic model in in-situ stress inversion shows advantages in improving the accuracy of in-situ stress calculation. In addition, based on the inversion analysis of in-situ stress near the Guodishan fault, we believe that the fault structure has a significant impact on the distribution of in-situ stress. Within the elevation range of − 400 m to − 800 m, the horizontal stress and vertical stress of the footwall are greater than those of the hanging wall. Moreover, the K ratio near the fault is generally less than 1, but the K ratio in the footwall is usually greater than that in the hanging wall, indicating that the tectonic stress has a stronger influence on the footwall. It is worth noting that the stress gradient near the fault is higher, which may lead to higher disaster risk.

The finite difference model and particle flow model were constructed to reproduce the process of coal and gas outburst in front of the tunnel. The reliability of the particle flow model was verified by studying the internal stress, gas pressure, and related parameters of gas and coal two-phase flow. Then the process of coal and gas outburst is described from a microscopic perspective. The results show that the particle flow numerical model of coal and gas outburst is in line with reality and can intuitively and conveniently monitor relevant parameters; The concentrated stress caused by excavation of tunnels can reach 1.2 times the in-situ stress; High stress causes the adhesion between coal particles to break down, which is the main reason for the initiation of coal and gas outbursts; The intermittent breakthrough of gas on the coal particle collection that blocks the release channel has caused pulsating characteristics of coal and gas outbursts.

The crack closure in impact coal seams induced by high-pressure air blasting greatly affects gas drainage efficiency. The length of the crack closure was calculated and analyzed based on energy and elastic theories. The closure region was then determined to be 3.8 m from the blasting hole. The results of a high-pressure air blasting experiment in the underground of one coal mine in China showed that the effect of crack closure on gas drainage efficiency manifested as a decreased amplitude of gas emission in the crack closure region. At 1.0–4.0 m from the blasting hole, the amplitude of gas emission in the observation holes first increased and then decreased with increasing distance from the blasting hole. At 1.8–2.5 m from the blasting hole, the amplitude of the gas emission was maximal. At 4.0 m from the blasting hole, the crack was nearly closed, and the gas emission in the observation holes was minimal. The theoretical calculation had good consistency with the field test results; thus, it can provide an important reference for an appropriate arrangement of gas drainage boreholes.

In recent years, tunnel-boring machines (TBMs) have been widely applied in deep coal mining. Turning is an inevitable challenge in TBM tunneling, and a TBM turning roadway exhibits greater instability than a straight roadway, as engineering experience has indicated. This study aimed to explore the failure mechanism and evaluate the support performance of a deep-turning roadway. Several numerical models were established to investigate the deformation of the roadway, the stress distribution, and the failure zone of the surrounding rocks under different tunneling conditions. The results show that the tunneling depth influences the failure pattern of the turning roadway: deep tunneling with high in situ stress can cause asymmetric failure of the turning roadway, while shallow tunneling with low in situ stress does not. Moreover, the change in turning radius, namely the change in roadway geometry, does not influence the stability of the turning roadway. In addition, the support actions for both the straight and turning roadways do not differ significantly, and the amount of controlled deformation of the surrounding rocks is proportional to their natural deformation.

In-situ stresses are significantly important for underground mining geotechnical design and coal seam gas management in underground coal mines. The past research always assumed an isotropic elastomer in the rock mass so that they could propose multivariate linear regression to predict the in-situ stresses. However, such a method normally led to a huge error if some extreme ground conditions presented such as massive bedding structures and frequent variations in the dip angles of discontinuities. The Guodishan fault area has complex geological conditions. In order to study the distribution characteristics of regional geostress field, this paper established an accurate 3D geological model of the area near the Guodishan fault by Rhino. Combined with the idea of large-scale transverse isotropy, we successfully extrapolated the original in-situ stress near the fault by using finite difference software, and determined the relationship between the gas hazard of coal seam in the fault and the in-situ stress. It was found that the 3D model development in Rhino could increase the accuracy of the geological conditions so that the accuracy of the in-situ stress inversion can be improved consequently. Based on the transverse isotropic modelling methods for numerical calculations, a more accurate in-situ stresses field could be obtained. The coal seam F_16-17 at the foot wall of the fault has a K ratio greater than one indicating a significant influence of the fault structures on the in-situ stresses distribution. Between levels − 300m and − 900m, the seam at the hanging wall area of the fault is deeper than seam at the foot wall area leading the original in-situ stress at hanging wall as much as 1.69 times that at the footwall. This would pose a greater gas risk in the hanging wall area than the foot wall area. The area close to the fault has a higher stress gradient which might lead to a higher risk of hazards.

The finite difference model and particle flow model were constructed to reproduce the process of coal and gas outburst in front of the tunnel. The reliability of the particle flow model was verified by studying the internal stress, gas pressure, and related parameters of gas and coal two-phase flow. Then the process of coal and gas outburst is described from a microscopic perspective. The results show that the particle flow numerical model of coal and gas outburst is in line with reality and can intuitively and conveniently monitor relevant parameters; The concentrated stress caused by excavation of tunnels can reach 1.2 times the in-situ stress; High stress causes the adhesion between coal particles to break down, which is the main reason for the initiation of coal and gas outbursts; The intermittent breakthrough of gas on the coal particle collection that blocks the release channel has caused pulsating characteristics of coal and gas outbursts.