Abstract Hard rock failure and rockburst hazards under high in situ stresses have been the subject of deep mechanics engineering. Previous investigations employed cubic specimens with a central hole for simulation fracturing around tunnels at laboratory scale, while characteristics crack evolution behavior different shapes holes induced by excavation unloading response barely considered. A commercially combined finite‐discrete element method (combined FEM/DEM) was used to investigate...

With the increasing of coal mining depth, conditions are deteriorating, and dynamic hazard is becoming more likely to happen. This paper analyzes relations differences between rockburst in mine metal mine. It divides into two types including static loading type during roadway excavation process face advancing. proposes correlation formation evolution overlying strata spatial structure stope, criterion occurrence, new classification, predictive evaluation method for that damage (RDE) =...

Abstract To solve the problem of controlling stability small coal pillars under mining disturbance adjacent working face, fourth panel 403 and 404 faces Gaojiabao mine with two roadways is taken as object this research. The comprehensive research method combining mechanical theory analysis, dynamic experiments field engineering practice was adopted. First, analysis determined magnitude frequency fracture‐related loading on overburden roof face; next, strain stress threshold indicators body,...

Abstract The successful retaining of the gob‐side entry under a thick and hard roof stratum is difficult because high pressure present complex construction technology commonly used. To solve this problem, new type supporting system proposed in paper. This mainly composed concrete‐filled steel tubular columns (CSTCs), flexible cushion, gob isolation structures. combines high‐strength support CSTCs with cushion bodies simple to construct, enabling fast efficient stratum. range strata...

Abstract Slabbing failure and strain rock burst are the main patterns during excavation construction phases of deep tunnels in hard brittle rock, which cause unexpected equipment damage casualties. This study presents a numerical simulation with an unloading central hole within specimen laboratory scale. A combined finite element/discrete element method (FEM/DEM) reproduces crack initiation, propagation, coalescence around entire process. The influence sectional shapes, rates holes, situ...

The interaction of mining and the surface water or aquifer system in varying overburden strata conditions is one most critical aspects sustainable practices, that can lead to loss inrush into openings. This paper examined this phenomenon a complex condition via case study, proposed new design minimize impact longwall on overlaying aquifer. A range factors have been identified contributing potential disturbance aquifer, including extent water-rich area, characteristics rock units, development...

The supporting technology of retaining small coal pillars in a double roadway layout can effectively relieve the tension mining and excavation replacement improve recovery rate. critical difficulty is that structure on both sides pillar has not established an effective mechanical connection, improvement bearing capacity limited, so it difficult to achieve long-term stability control pillar. Taking 301 302 working faces Gaojiapu Coal Mine as engineering background, this paper first constructs...

The rock mass around deep roadways has obvious creep characteristics in high-stress environments. Meanwhile, the cyclic impact load induced by roof fracturing also causes dynamic damage to surrounding rock, leading long-term large deformation. This paper examined deformation mechanism based on theory of perturbation effect considering sensitive zone. study proposed a stability control guideline for under load. An innovative support system was developed roadways, with concrete-filled steel...

In this study, a wide strain measurement range optical frequency domain reflectometry (OFDR) system based on self-correcting two-dimensional (2D) cross-correlation is proposed and experimentally demonstrated. Large events can lead to spatial mismatch caused by overstretching of the fiber, resulting in inaccurate demodulation spectrum during conventional OFDR data processing. The degradation signal similarity due be mitigated creating 2D array reference signals with different positional...

Abstract Methane drainage method should be used before coal mining of many modern collieries because venti lation air methane is in sufficient to keep level within regulation values. The technology high drilling (HDMD) has been for although its effect not very stable due parameter design. height the fracturing zones determined mostly according empirical formula, on-site observation and numerical simulation analysis. In this paper, a was introduced determining f ract uring (AFZs) based on...

Large–scale underground coal mining is bound to cause serious surface subsidence problems. However, conventional filling and methods have problems such as high cost process difficulty. In order achieve the purpose of efficiency low cost, this paper proposes using technology CGSG. To effective control overburden strata movement ground settlement cemented gangue strip in goaf (CGSG), studies design principles key parameters strip–filling structure including strength, compressed deformation...

ReseaRch on application of stRip Backfilling Mining technology -a case studyStrip backfilling mining is great significance for eliminating coal gangue, improving recovery rate, harmonizing the development between resources and environment in diggings.This paper firstly analyzed roof control mechanism, deformation failure mechanism characteristics filling body through theoretical analysis.Then, numerical simulation combined with geological conditions site, a gangue strip scheme was designed...