scholarly journals Mechanism by Which Backfill Body Reduces Amount of Energy Released in Deep Coal Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Wenyue Qi ◽  
Jixiong Zhang ◽  
Nan Zhou ◽  
Zhongya Wu ◽  
Jun Zhang
Keyword(s):  
Energy Density ◽  
Coal Mining ◽  
Coal Mine ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Mining Area ◽  
Filling Material ◽  
Ultrahigh Energy ◽  
Energy Density Distribution ◽  
Working Face

Deep coal mining is unavoidable, and the complex mining environments and the increasing dangers associated with ultrahigh energy accumulation and release from mining disturbances renders it extremely difficult to maintain a safe and stable stope. Solid backfilling technology directly uses coal gangue and other solid wastes in the mining area to fill the gob after mining. Support from the backfill body can inhibit the movement of overlying rock strata and significantly alleviate the influence of mining. In this study, the correlations between the deformation of gangue filling material and the characteristics of energy dissipation were examined under lateral uniaxial compression. The strain energy density distributions of backfilling and caving mining methods were simulated using numerical modeling. The results showed that the strain energy density distribution of backfilling mining was less concentrated, and its peak value was lower than that of caving mining by 51.0%, indicating that backfilling could effectively reduce the amount of energy released from mining rocks. The dense backfill mining area of the No. 9301 face in Tangkou Coal Mine was used as a case study. Measures for controlling the backfill body compaction for reducing the amount of energy released from mining rocks were proposed. These measures include optimizing the support structure and filling material formula, controlling the preroof subsidence, and ensuring an appropriate number of tamping strokes. The monitoring results of the backfilling quality, surface subsidence, and microseismic energy of No. 9301 working face in Tangkou Coal Mine showed that when the backfill body filling ratio control value was 82.28%, the total number of microseisms and the amount of energy released from the mining working face were significantly lower compared to those of the caving method. This study demonstrated that the backfill body could effectively reduce the amount of energy released from mining rocks, thereby realizing management of mine earthquake and sustainable deep coal mining.

scholarly journals Control Effects of Five Common Solid Waste Backfilling Materials on In Situ Strata of Gob

Energies ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 154 ◽  
Author(s):  
Peng Huang ◽  
Sam Spearing ◽  
Feng Ju ◽  
Kashi Jessu ◽  
Zhongwei Wang ◽  
...  
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Coal Ash ◽  
Gangue Mineral ◽  
Aeolian Sand ◽  
Working Face ◽  
Backfill Materials ◽  
Mineral Waste

Solid backfill mining as a green mining method has already been successfully applied in many mine sites. Higher requirements for the backfilling materials have been put forward in special regions, such as shallow coal seams, ecologically susceptible areas, and sites with building on the surface. The control effects of common backfilling materials on in situ strata of gob need to be studied and compared to ensure the suitable materials are applied in the mine. The meso-structure, stress variation, energy dissipation, and backfilling effects of the five common solid backfilling materials, which are Aeolian sand, gangue, mineral waste residue, coal ash, and loess are analyzed in this paper. The results show that the Aeolian sand and gangue are densely packed and internally hard when compared to other backfill materials. The deformation of the five materials to absorb the same amount of energy in the order of higher to lower was determined as Aeolian sand, gangue, mineral waste residue, coal ash and loess. The Aeolian sand’s strain energy density is 1.67 times larger than the loess, however, the Aeolian’s strain energy density in front of working face is just 32.2% of the loess, which is important to ensure the safety of the working face. The stress changes were monitored in situ with Aeolian sand and gangue as backfill materials. The monitoring results show that the Aeolian sand stress increase rate is quicker than gangue, which can support the roof effectively.

The effect of cement mantle thickness on strain energy density distribution and prediction of bone density changes around cemented acetabular component

2018 ◽  
Vol 232 (9) ◽  
pp. 912-921 ◽  
Author(s):  
Devismita Sanjay ◽  
Subrata Mondal ◽  
Richa Bhutani ◽  
Rajesh Ghosh
Keyword(s):  
Energy Density ◽  
Density Distribution ◽  
Acetabular Component ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Cement Mantle ◽  
Thickness Variation ◽  
Acetabular Cup ◽  
Energy Density Distribution ◽  
Mantle Thickness

Cement mantle thickness is known to be one of the important parameters to reduce the failure of the cemented acetabular component. The thickness of the cement mantle is also often influenced by the positioning of the acetabular cup. The aim of this study is to determine the effect of uniform and non-uniform cement mantle thickness on strain energy density distribution and prediction of the possibility of bone remodelling around the acetabular region. Furthermore, tensile stress distribution in the cement mantle due to non-uniform cement mantle thickness was also investigated. Three-dimensional finite element models of intact and 17 implanted pelvic bone were developed based on computed tomography data sets. Results indicate that implantation with non-uniform cement thickness variation in the anterior–posterior direction has a significant influence on strain energy density distribution around the acetabulum as compared to thickness variation in the superior–inferior direction. Increase in density is predicted at the anterior part of the acetabulum, whereas density decrease is predicted at the posterior, inferior and superior part of the acetabulum. The non-uniform cement mantle thickness affected the tensile stress distribution in the cement mantle, in particularly superiorly placed acetabular cup. This study concludes that uniform cement thickness is desired for the longer success of the cemented acetabular component.

scholarly journals Explosion-Induced Stress Wave Propagation in Interacting Fault System: Numerical Modeling and Implications for Chaoyang Coal Mine

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaojun Feng ◽  
Qiming Zhang ◽  
Muhammad Ali
Keyword(s):  
Energy Density ◽  
Stress Wave ◽  
Coal Mine ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Stress Waves ◽  
Fault System ◽  
Propagation Process ◽  
Geological Engineering ◽  
Induced Stress

Exploring the propagation of stress waves in rocks with preexisting discontinuities is of great importance to reveal rock and geological engineering problems, particularly dynamic disasters like earthquakes and rockbursts in underground coal mining. In this paper, six 3D models established with COMSOL Multiphysics are employed to explore the influence of two preexisting faults with different orientations on the propagation process of explosion-induced stress waves and the reflection effect. Considering the propagation process of stress waves, the interactive effect between two different size faults is discussed. The results show that the dip angles of the preexisting fault and the differences of the elastic modulus, density, and Poisson’s ratio between faults and rocks have great influence on the distribution of stresses and strain-energy density. Immediately after the stress wave induced by blasting arrived at preexisting fault A, a relatively high concentration of the strain-energy density was observed at the last wave before passing through fault A. The presence of faults leads to the reflection of most of the blast energy. When the stress wave propagates across fault A, the strain energy stored in the stress wave becomes attenuated; thus, most strain energy was absorbed by the fault’s domain. Finally, the modeling results were implicated in Chaoyang Coal Mine to account for the distribution of the observed seismic events. This study has guiding significance for the attenuation law of stress waves passing through joint/fissure zones in geological engineering, earthquake engineering, and underground mining engineering.

scholarly journals Volume free strain energy density method for applications to blunt V-notches

2020 ◽  
Vol 28 ◽  
pp. 734-742
Author(s):  
Pietro Foti ◽  
Seyed Mohammad Javad Razavi ◽  
Liviu Marsavina ◽  
Filippo Berto
Keyword(s):  
Energy Density ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Density Method ◽  
Free Strain
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