Taking the return-airway 4204 with roof cutting in Longquan Coal Mine as engineering background, structure, key parameters, and deviatoric stress evolution were studied. Conclusion: The Key Stratum within a 4-8 times mining height is considered Near Stratum. Cutting makes it possible to form cantilever structure of on solid coal side, which more conducive stability gob-side roadway. During angle 90-55°, increases linearly, increase rate pillar > floor. While length from 0 35 m, decreases...

To study the occurrence mechanism of rock burst during mining irregular working face, took panel 7447 near fault tectonic as an engineering background. The spatial fracture characteristic overlying strata was analyzed by Winkler elastic foundation beam theory. Furthermore, influence law width to suspended and limit breaking span key were also thin plate Through micro-seismic monitoring, theoretical analysis, numerical simulation resistance support field measurement, this investigated in...

Mining-induced subsidence is critical for ecological environment reconstruction and damage prevention in coal mining areas. Understanding the characteristics of surface with multi-seam first step. Surface different panel layout configurations was investigated by means UDEC numerical simulation. Based on simulation results, it indicated that configuration had a significant impact subsidence, including ground horizontal displacement, crack propagation, fissure development. The overlapped...

The low permeability of coal seams makes gas drainage difficult in lots mines. This study presents a low‐temperature, safe, and efficient liquid carbon dioxide phase transition explosive technology (LCDPTET) to increase the coal, thereby improving efficiency eliminating dangers outburst. Meanwhile, an integrated approach for experimental determination, numerical simulation, field testing was applied damage ranges determine reasonable spacing between hole blast hole. A simulation model...

The key parameters of pressure relief pre-splitting blasting technology (PRPBT) contribute to the implementation effect goaf-side entry by roof cutting (GSERC). This study is an attempt design including height, angle, spacing between boreholes, charge structure and sealing length using theoretical analysis, numerical simulation field implementation. basic quality index main 666.27, combined with peeping observation result, belongs category a hard roof. Different from weakened compound roof,...

In order to research protected layer pressure relief effect under influence of different width coal pillar, this paper carried on FLAC3D numerical simulation vertical stress field and deformation pillar width. The evolutional characteristics stress, displacement affection which affected were analyzed. results show that: (1) Coal zone is high concentrated zone. Because influence, trended distribution from "v shape" "partial saddle shape"; tendency "flat disc shape". Vertical non-linear with...

Abstract Predrainage of gas by cross‐boreholes is an important method to prevent coal and outbursts in the process a roadway excavation. Limitations technologies poor effects preventing occur seam with soft layer. In this study, new hydraulic caving technology for has been proposed solve problem. A CT equipment was used observe development fissures around The plastic zone range permeability distribution ordinary slotting also were compared numerical simulation. field test taken Xuehu Mine...

Mining-induced ground fissure (MIGF) contributes to vegetation deterioration, landslides and other natural hazards.The study is an attempt reveal the development type, dynamic process, formation mechanism of MIGF for MIGF-induced hazard prevention shallow burial coal seam mining.A novel approach including in situ measurement, theoretical analysis, numerical simulation was implemented.There are two typical types fissures, namely sliding-type fissures stepped-type fissures.Sliding-type...

The principal stress difference is introduced as a new evaluation index in order to better understand the failure mechanism of roadways affected by upper coal pillars and characterize rock mass. Compared with traditional methods, it facilitates quantitative analysis. Moreover, we combine semiplane theory obtain distribution on pillar’s bedrock strengthening control area from “change point” position along 21 m horizontal line. influence multiple stresses induced mining roadway analyzed. It...

Abstract In this study, we present a comprehensive investigation of the ground stability gob‐side entry by roof cutting in relation to mining stage, based on field measurements, theoretical analysis, numerical simulation, and situ practice. Differing from normal mode entry, mining‐induced stress strain evolution under (GSERC) is extremely complex, unreasonable support can cause serious deformation collapse GSERC. Taking Dadougou coal mine as engineering background, response, rock mechanics...

The mining-induced ground response (MIGR) has a critical impact on safety management, the mining plan, and entry support. A clear understanding of characteristics is foundation MIGRs scientific control. This study result development non-pillar panel with gob-side by roof cutting (GSERC). Comprehensive research in situ measurements, numerical simulation, theoretical analysis to determine characteristics, including GSERC, were implemented. results indicate that MIGR presents characteristic...

In order to research the law of mine pressure and roof control in shallow buried coal seam, based on a comprehensive summary theory, technology application, engineering practice, summarized results status, analyzed shortage, proposed proposals. The show that:1“short masonry beam” “step structure mechanical model “key stratum seam theory” has provided theory basis for guidance. 2Rock soil (bedrock alluvium) coupling mechanism, loose layer dynamic theory," mining, water retention, ecology...

Taking Tangkou Coal Mine 430 belt transport roadway as the engineering background, field measurement, numerical simulation, and theoretical analysis are adopted to study evolution of zonal disintegration in axial compression coefficient 1.0 ~ 2.6. Conclusions below: The main fracture zone straight-wall semicircular arch approximately shows a " shape. An increase stress promotes formation multi-layered disintegration, addition, causes more surrounding rock enter into plastic state. chord...

Abstract Taking the double wide-strip mine gangue backfilling work face of 1101 and 1102 in Tingnan Coal Mine as background, this study utilizes theoretical analysis, numerical simulation, laboratory experiments, engineering practices to investigate complete process compression-consolidation-creep-diagenesis compacted backfill body, equivalent mining height model, surface subsidence characteristics. The results: maximum control roof distance face=Tip-to-face + Cutting depth Roof beam length...

Abstract Traditionally, the study on bearing structure of overlying strata mainly focuses bedrock with effect unconsolidated layer. It simply considered as uniformly loading top interface bedrock, and ignores for Combined geological conditions shallow burial thick layer in Shendong mining area,the mechanical model arch layers was established. The relationship between height span analyzed theoretical formula dynamic evolution mechanism studied numerical simulation. Besides, ultimate derived....