Abstract The large‐scale mining of coal resources promotes the formation section pillar groups between working faces. overlying strata are supported by pillars, which leads to a unique fracture‐bearing structure in key stratum, resulting evolution fissures (cracks) and generally high load on supports. Studying formed pillars (fissures) is basis for realizing rational Here, characteristics pillar‐overburden rock shallow seam resistance support with stable fracture bearing overburden were...

This paper aims to address the issue of hydraulic support crushing accidents or failures in retracement roadway (RR) that frequently occurs when a fully mechanized mining face is retraced during end-mining stage. The deformation and instability mechanism surrounding rock RR end at Hanjiawan Coal Mine located northern Shaanxi area explored through field measurement, theoretical analysis, similar simulation, numerical simulation. results reveal stability remaining coal pillar (RCP) fracture...

The isolated working face is significantly impacted by the adjacent goaf and mining activities of itself, causing overlying rock layers above to exhibit far more intense activity compared an ordinary face. stress levels are high, surrounding suffers severe damage, posing serious challenges safe efficient extraction Improving service life retreating roadway in a pressing technical issue that coal companies must address. Focusing on characteristics strata conditions 8213 Yanjiahe Coal Mine,...

To address the intense mining pressure and dynamic accidents, such as shield collapse during in shallow coal seams crossing Maoliang terrain, this study focuses on Panel 30206 of Yanghuopan Coal Mine. Through theoretical analysis, numerical simulation, field measurements, stress transfer patterns changes loads were analyzed, mechanism calculation method for maximum support resistance determined. The results show that when working face enters load-affected zone base load ratio overburden...

To overcome the limitation of traditional elastic phase field models that neglect plastic deformation in rock compressive-shear failure, this study developed an elastoplastic fracture model incorporating strain energy and established a coupling framework for crack evolution. By introducing non-associated flow rule damage variable, functional comprising energy, work, surface was constructed. The governing equation considering plastic-damage obtained, enabling simulation evolution from stage...

The pressure relief of coal pillars in close-distance multi-coal seam goaf is a complex engineering problem with the characteristics “dynamic mine pressure”. Hence, this paper studies such problems. First, influence factors pillar on mining face lower under condition were theoretically analyzed, and it was concluded that vertical stress most important element, followed by horizontal stress. Next, physical similarity simulation experiment designed to study distribution law floor before after...

To study the deformation and failure mechanisms of soft rock mining roadways, 1506 return airway Anyang Coal Mine is taken as engineering background. Based on limit analysis theory, a model based rigid slider system constructed to assess surrounding roadway. The formulas for calculating self-weight power in velocity discontinuity line roadway, work pressure, energy dissipation rate are derived, upper objective function height obtained. characteristics fracture evolution process under...

Shallow coal seam mining makes the evolution form of fissures in rock and soil layers diversified, which leads to easy penetration as main channel water, sand inrush, air leakage. In order reveal co-evolution mechanism broken beam structure key strata, taking Hanjiawan Coal Mine research background, relationship between structure, fissure activation period, propagation characteristics, connectivity working face was studied by means field observation, physical similarity simulation,...

Abundant industrial experiences have shown that directional air drilling technology is effective for gas drainage when broken and soft coal seams. In this paper, the Eulerian–Eulerian model was used to simulate gas–solid two-phase flow behavior of compressed transporting dust in The relationship between degree deposition, annular pressure law, transportation dust, aforementioned factors rotational speed, particle size, volume could be determined. results indicate size plays a significant...

Abstract In northern Shaanxi province, the coal seam deposit conditions are generally characterized by large thickness and shallow depth of burial, phenomenon pillar sloughing is serious in process working face retrieval, which brings great potential danger to mine safety production. this paper, monitoring stress damage field section, changes degree different stages determined. A new mechanical model a thick constructed structural breakage law each section obtained, transfers mechanism...

With the gradual increase in mining depth of coal resources, destruction rock structure inter-layered near seam under influence has led to frequent occurrence water-inrush disasters mines, which seriously affects safety mine production and people underground. Therefore, it is important study mechanism water inrush between seams control protect loss groundwater resources. This paper takes Hanjiawan with typical stratigraphic characteristics as background for research studies structural...

A PANDA polarization-maintaining few-mode ring-core fiber (PM-FM-RCF) structure with two air holes around the ring core is proposed. The relative mode multiplicity factor (RMMF) defined to evaluate spatial efficiency of designed PM-FM-RCF. performance analysis and comparison proposed PM-FM-RCFs considering three different types step-index profiles are detailed. Through modal characteristic numerical simulation, PM-FM-RCF a lower refractive index difference (Δnoi=1.5%) between inner central...

This paper focuses on the failure mechanism of a water‐resisting soil layer with both coal excavation and seepage effect. Being taken simulation principle fluid‐solid coupling as research basis, we have established new kind experimental material for physical (FPS). The adopts river sand clay aggregates, besides engine oil low‐temperature grease that are used gelatinizing agents. According to relevant property testing material, mechanical parameters totally match layer, which satisfy...

China is rich in coal resources under water bodies. However, the safety prediction of high-intensity mining bodies has long been one problems encountered by industry. It great significance to realize safe bodies, improve recovery rate and protect reservoir resources. Therefore, this article takes No. 5 seam 11 area Wangwa Coal Mine as research object, integrates physical simulation, numerical theoretical analysis, other methods study development height water-conducting fracture zones fully...

Abstract To investigate the significant deformation of surrounding rock within dynamic pressure zone gateroad, this study utilized tailgate 1506 longwall face in Anyang Coal Mine as engineering context. A combined approach field measurement and numerical analysis was employed to explore failure mechanisms under pressure. The findings indicate that before exploitation face, there a notable reduction stress across floor immediate roof, with minimal concentration observed coal pillar entity rib...

The mining of shallow coal seam groups triggers the activation overlying strata, leading to increased pressure and support difficulties, thereby posing a threat safe extraction underlying seams. Against backdrop Longhua Coal Mine, this study utilized physical similarity simulation experiments obtain activated, restructured load-bearing structure migration characteristics strata. Theoretical calculations were employed establish both rolling friction mechanics model for activated mechanical...