Oxygen functional groups play a key role in the process of coal spontaneous combustion, and aldehyde are one main oxygen groups, but their reaction pathways still unclear. Based on quantum chemical calculation method, this study used density theory (DFT) Gaussian software to explore oxidation self-reaction combustion. The Ph–CH2–CHO was selected as characterization molecule containing group, results showed that C–H bonds formed by s–sp2 hybridization active sites. During process, hydrogen...

To study the adsorption and diffusion behavior of methane on coal macromolecules under different moisture contents, macromolecular model coking was established through elemental analysis 13C NMR X-ray photoelectron spectrum (XPS) experiments. Using this molecular model, variation capacity five contents (0, 1.4, 2.3, 3.2, 4.4%) investigated. The effect explained from energy distribution radial function (RDF). Finally, studied according to coefficient. Simulation results indicate that absolute...

The "three stages" division of coal spontaneous combustion is fuzzy and lacks adequate risk warning levels corresponding to its divisions; additionally, the targeted prevention measures for each stage have not been described. To address shortcomings division, "five was proposed more clearly analyze changes coal. method divides process into five stages, including: latent stage, heat accumulating evaporation active hypoxic stage. critical point determined using adiabatic oxidation experiments...

To ascertain the evolution of pore characteristics and methane adsorption unit cell Nanshan 1/3 coking coal under different stresses, proximate analysis, ultimate solid-state

To improve the safety level of pile foundation construction for offshore wind power, in this study, risk indicators were evaluated using analytic hierarchy process (AHP) and comprehensive evaluation methods. The operation power mainly includes four phases: preparation construction, sinking, end scour protection construction. Pile are systematically identified as human factors, material management environmental factors. most important AHP methods, which included five indicators: piling...

Abstract Based on the geological conditions of overburden rock, dynamic development law breakage was investigated by theoretical analysis and similarity model experiments in this paper. The formula compressive strength No. ratio obtained testing cylinder samples similar materials. It can be seen from fracture evolution established calculations that overlying rock layer’s is consistent. Additionally, height “three zones” angle are basically Obtaining synchronous collapse strata controlled key...

The coal spontaneous combustion phenomenon seriously affects the safety production of mines. Aiming at problem complex molecular structure and incomplete reaction sequences present, mechanisms thermodynamic parameters chain reactions were explored by combining experimental detections simulations. First, active groups on surface obtained Fourier transform infrared spectroscopy (FTIR), mainly including methyl (-CH3), methylene (-CH2), methyne (-CH), phenolic hydroxyl (-ArOH), alcohol (-ROH),...

To comprehensively elaborate the formation characteristics of hydration films on 1/3 coking coal molecule, this paper reports construction a realistic simplified model for calculations electrostatic potentials molecular surface to foresee major immersion locations. On basis, interactions at interface molecules with different numbers water and their effects each functional group were investigated. Using scanning electron microscopy experiment, changes in matrix before after leaching compared...

The effects of H2O on the low-temperature oxidation characteristics coal have always been one keys in research spontaneous combustion, but most studies rely experiments for macroscopic derivation, and theoretical researches at microlevel are rarely mentioned. In this paper, phenylacetaldehyde, phenylethyl alcohol, phenylacetic acid, ethylbenzene hydroperoxide were used as modeling compounds molecules containing aldehyde (−CHO), alcohol hydroxyl (−OH), carboxyl (−COOH), peroxide (−C–O–OH)....

For determine the optimum position of roof low roadway, optimal solution is derived according to response surface methodology. The UDEC numerical simulation overburden gives porosity distribution strike fractured zone, upper limit heights caving zone and are obtained as 18 m 65 m, respectively. Based on distribution, FLUENT models goaf air inlet return working face roadway were established simulate gas concentration in corner drainage volume during mining. Using vertical horizontal distance...

In the process of deep mining, coal‐rock masses were subjected to different types’ disturbance dynamic loading, and they propagated depth coal rock in forms stress waves. It has been determined that mainly show shear‐compression failures under static pressure. However, had consistently demonstrated crashing or splitting failure, which showed strong mechanical characteristics. Therefore, propagation interaction waves have great effect for dynamical damage masses. The current research...

To design underside protective seam strip layout. Similarity model experiments, numerical simulations and theoretical calculations are used to quantitatively study the pressure relief protection effect of different widths, dip angles coal pillar widths a thin under deeply buried conditions. The optimal width range is obtained according change law strain during mining process in similar experiment. expansion protected fitting surfaces among angle with distance along strike established...

Abstract To research the dynamic response characteristics of coal mass under impact loads, based on LS-DYNA software, rigid body bars are simulated to different speed conditions, and distribution stress, strain energy analyzed. The results demonstrate that (1) peaks axial radial stresses central axis line obey power function distribution; at same position, stress close, peak is from much larger than close to. (2) generate tensile in propagation directions, respectively, prone damage stress....

In order to study the relationship between China's safety production indicators and economic social indicators, development trend of indicator data in past 20 years was statistically analyzed, qualitative quantitative research conducted using grey relational analysis multiple linear regression methods. two decades, there has been a significant improvement number deaths, work-related injuries, occupational patients production, country's three categories 14 have achieved rapid development....

To mitigate accidents in submarine cable construction within the rapidly expanding offshore wind power sector, this study employed analytic hierarchy process (AHP) and risk matrix method (LS) to assess risks associated with identified factors. Based on project research expert consultations, five primary twenty-two secondary factors were identified. AHP was utilized rank by severity, probability, detection difficulty, highest being environmental impact, followed third-party destruction worker...

To research the dynamic response characteristics of cylindrical coal-rock samples under impact loads, rigid bars on is simulated different speed conditions, based LS-DYNA software, and distribution stress, strain, energy are analyzed. The results demonstrated following: (1) sample failed at center first, damage developed downward along axial direction. (2) critical effective stress strain have an exponential function relationship with velocity, time has a linear velocity. (3) change law...