Numerical Simulation and Analysis of Sand-Shale Ratio of Bedrock Impacting Mining Subsidence

2014 ◽  
Vol 962-965 ◽  
pp. 1195-1200
Author(s):  
Shi Jie Song ◽  
Xiao Guang Zhao ◽  
Nian Zhang ◽  
Lu Zhao
Keyword(s):  
Numerical Simulation ◽  
Layered Structure ◽  
Simulation Method ◽  
Mining Area ◽  
Mining Subsidence ◽  
Overburden Rock ◽  
Coal Mining Area ◽  
Basic Law ◽  
Set Up ◽  
Coal Measures

Significant geological factor of coal occurrence is layered structure of coal measures overburden rock, and bedrock sand-shale ratio is a key element of coal measures overburden rock layered structure. On the background of geological occurrence conditions of 2-2 coal in Yushen coal mining area, the sandstone layer, sandstone average thickness and sand-shale ratio are taken as variables to build the 18 different types of layered structure models. On this basis, basic law of coal measures bedrock sand-shale ratios which is a key characteristic of layered structure impacting mining subsidence is mainly studied by using numerical simulation method. The results show that: firstly, in spite of any condition of sandstone layer coefficient subsidence coefficient always decrease with the increase of sand-shale ratios. However, the effect of sand-shale ratios on subsidence coefficient continuously decreased with the increasing of sandstone layer coefficient. Secondly, when the sandstone layer coefficient is less than 70%, the different sand-shale ratios have significant influence on the subsidence coefficient, and when the sandstone layer coefficient is more than 90%, subsidence coefficients corresponding to different sand-shale ratios show obvious convergence characteristics. The gap between each other is only 1%~2%. Thirdly, taking the subsidence coefficient corresponding to the sand-shale ratio is 6:4 as reference, the curves about the rate of decrease in subsidence coefficient is set up when the sand-shale ratio is 7:3 or 8:2, and the fitting equations are presented on the basis of Log3P1 mathematical model.

Numerical Simulation on Blasting Fume Diffusion in Blind Roadway with FLUENT

2013 ◽  
Vol 663 ◽  
pp. 655-660
Author(s):  
Zhen Hua Xie ◽  
Zheng Lan Yuan ◽  
Yu Zhang
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Mining Area ◽  
Computational Grids ◽  
Actual Situation ◽  
Forced Ventilation ◽  
Iron Mine ◽  
Effective Ventilation ◽  
Set Up ◽  
And Diffusion

Aiming at the generation of blasting fume in underground blind roadway, numerical simulation method was taken to obtain the diffusion law of the blasting fume. In accordance with the actual situation in Shachang mining area of Shouyun iron mine, the physical model and mathematical model were set up, computational grids were divided, and the boundary condition was established. The diffusion law of blasting fume and the completion time under different explosives dosage were simulated by Fluent. The laws of blasting fume diffusion and diffusion time changing with the amount of explosive in local fan forced ventilation were obtained. The results can provide a theoretical basis for the research of a reasonable and effective ventilation manner of blind roadway.

Heat Exchange Calculation of a Regenerative Air Heater with Numerical Simulation Method

2013 ◽  
Vol 860-863 ◽  
pp. 1416-1419
Author(s):  
Ri Guang Wei ◽  
Zhen Xiao Qu ◽  
Jian Qiang Gao
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Calculation Model ◽  
Design Parameters ◽  
Practical Calculation ◽  
Air Preheater ◽  
Air Heater ◽  
Pulverized Coal Boiler ◽  
Set Up ◽  
Coal Boiler

According to the structure and working principle of rotary air preheater,the heat transfer calculation model is set up with reasonable simplification. Combining with the design parameters of the rotary air preheater of a 400 t/h pulverized coal boiler unit ,the results of practical calculation show that the said thermodynamic calculation method not only has higher precision of calculation,but also can get the temperature distributions of the gas, air and heat surface in each cross-section of the rotary air preheater. The result of numerical simulation calculation tallies well with the original designed data. It can be used for the heat calculation both two-sectorial and three-sectorial air heater; it can be used for performance analysis of the regenerative air heater.

Numerical Simulation of Pyroclastic Flow at Mt. Semeru in 2002

2019 ◽  
Vol 14 (1) ◽  
pp. 116-125
Author(s):  
Makoto Shimomura ◽  
Wilfridus F. S. Banggur ◽  
Agoes Loeqman ◽  
◽  
Keyword(s):  
Numerical Simulation ◽  
Friction Factor ◽  
Pyroclastic Flow ◽  
Sudden Change ◽  
Simulation Method ◽  
Active Volcano ◽  
Flow Path ◽  
Pyroclastic Flows ◽  
Set Up ◽  
The Individual

Mt. Semeru (3676 m asl.) is an active volcano in Indonesia. Mt. Semeru has a specific topography i.e., a large straight scar in its south-east flank. The geometry of the scar is approx. 2 km in length and 300–500 m width. The scar is connected to three major drainage channels: the Kobokan River, the Kembar River, and the Bang River. On December 29, 2002, a pyroclastic flow (PF) with an approximate volume of 3.25 × 106m3was generated and it traveled 9–11 km along the Bang River. This pyroclastic flow was the largest among the ones generated from 2002–2003 eruptions of Mt. Semeru. All prior recorded pyroclastic flows traveled 1–2.5 km along the Kembar channel. Thus, this pyroclastic flow suddenly changed its flow path, and it traveled more than three times longer than its antecedents. To investigate the cause of the sudden change, a simulated reproduction of this pyroclastic flow was carried out by employing the numerical simulation method proposed by Yamashita and Miyamoto (1993). Due to the uncertainty of the volume of each pyroclastic flow and the temporal change of deposition thickness, a total of 12 simulation cases were set up, with variations in the number of sequence events, the duration of inflow at the upper reach of the flow, and the inter-granular friction factor. The simulation results showed that to explain the sudden change in flow path, the Kembar channel, around 3 km from the vent, has to be buried by antecedent pyroclastic flows. Furthermore, the individual volumes of the prior flows must be less than 0.25–1× 106m3, with an inflow duration of less than 1 min. The friction factor must be set to be 0.5. By using the most acceptable case, the simulated pyroclastic flows were in good agreement with observed results. The results implied that careful investigation and continuous monitoring of the area at 1500–2000 m asl. on the south-east flank of Mt. Semeru are important to prepare for future pyroclastic flows.

Research on China’s Forest Carbon-Sink Policy Path in Coal Mines

2014 ◽  
Vol 1010-1012 ◽  
pp. 1903-1906
Author(s):  
Chuang Hong Shang ◽  
Zhi Hong Xu ◽  
Jun Wang
Keyword(s):  
Environmental Pollution ◽  
Coal Mining ◽  
Kyoto Protocol ◽  
Carbon Sink ◽  
Coal Mines ◽  
Mining Area ◽  
Forest Carbon ◽  
Government Policies ◽  
Coal Mining Area ◽  
Set Up

In post-Kyoto Protocol times, forest carbon-sink has become one of the key path choices to realize clean development for coal mining area to govern ecological environmental pollution. In practice, big challenge is to set up effective and systematic government policies for forest carbon-sink in coal mines. For China, it is just at beginning in policies. Currently, China’s forest carbon-sink policies for coal mines ought to be set up in terms of industry, finance and law.

scholarly journals The spatiotempora variations rules of Songzao coal mining subsidence based on numerical simulation

2015 ◽  
Vol 372 ◽  
pp. 403-409
Author(s):  
J. Lu ◽  
Y. Li ◽  
H. Cheng ◽  
Z. Tang
Keyword(s):  
Numerical Simulation ◽  
Coal Mining ◽  
Land Subsidence ◽  
Mining Area ◽  
Surface Subsidence ◽  
Mining Subsidence ◽  
Spatiotemporal Variations ◽  
Simulation Data ◽  
Subsidence Rate ◽  
Coal Mining Subsidence

Abstract. With the increasing demand of coal, coal mining at Songzao makes the area of land subsidence growing larger. Land subsidence in coal mining area not only made large subsided farmland out of production and caused the enormous loss to local agricultural production, but also brought a number of serious problems to the local social economy and ecology Environment. To use Probability-integral Method based on numerical simulation of Songzao Mine, its subsidence simulation data from 1999 to 2009 was obtained. Hence, overlay analysis between Goaf data and the simulation data in 2009, and between field investigation and the simulation data in 2009 were carried out. After the coal mining underground was identified as the crucial cause of surface subsidence. Therefore, the accuracy and feasibility of the simulation data had been verified, and the spatial pattern and spatiotemporal variations conforming to the actual values have been obtained. The results show five main findings. The first indicated that the surface subsidence is mostly located at the top of the Goaf, where the overlap areas between Goaf data and subsidence simulation data have accounted for 93.05 % of Goaf and 65.19 % of subsidence simulation data respectively. The second finding indicated that by end of 2009, the mining subsidence extent had reached about 5087.50 hm2. This area accounts for about 40 % of total of the mining area. The third finding indicated that within 10 years from 1999 to 2009, the influence range of subsidence has expanded about 2340.54 hm2, and the coal mining subsidence rate in Songzao Mine has increased gradually with time. Moreover, average increasing speed of the extent area in the second five years was larger than the first five years (about 75.08 hm2 yr−1 more). The fourth finding indicated that maximum subsidence has increased from 2.0 m in 1999 to 2.5 m in 2004, and then 3.0m in 2009 with subsidence rate of about 0.1 m yr−1. At the same time, the area affected by the subsidence 2.0 m in 1999 was more than twice the area affected by subsidence in 2004. This in return, it was more than 7 times larger than the area affected by subsidence in 2009 of the one affected by subsidence in 2004. Extent of the area affected by the 2.5 m subsidence has also enlarged rapidly. This area has expanded by about 40 times in 2009 than its value in 2004. In addition, the area of subsidence of value 3.0 m has reached about 0.44 hm2 in 2009 from zero value. Finally, the fifth finding indicated that the overall extend of the mining subsidence was much more serious in southern than in northern side of the Songzao Mine. Moreover, it was indicated that the increasing rate of mining subsidence in the western side of the study area was as bigger as in the eastern side between 1999 and 2009. The spatiotemporal variations rules of songzao coal mining subsidence based on numerical simulation could provide reference for the subsequent subsidence prevention and land consolidation.

Numerical Simulation of Stress Wave Propagation Induced by Cut Blasting in Multi-Media

2012 ◽  
Vol 249-250 ◽  
pp. 22-25
Author(s):  
Guo Liang Yang ◽  
Ren Shu Yang ◽  
Chuan Huo ◽  
Yu Long Che
Keyword(s):  
Numerical Simulation ◽  
Stress Wave ◽  
Strong Shock ◽  
Simulation Method ◽  
Stress Waves ◽  
Stress Wave Propagation ◽  
Weathered Rock ◽  
Plastic Damage ◽  
Multi Media ◽  
Set Up

Explosive blasting in rock and other media could induce strong shock wave. Near blasting zone, the blasting energy mainly break rock. Slightly far away from borehole, the blasting energy induces plastic damage. Farther afield, this kind of energy presents elastic deformation. In cut blasting, multi-boreholes initiate at the same time, multi-column stress waves occur superimpose and converge. Especially in multi-media, this process is extremely complex. Adopt numerical simulation method, set up multi-media model, which include weathered rock, highly weathered rock and plain fill. This paper simulated the propagation process of stress wave in these medias. Revealed the propagation mechanics of stress wave.

Use of D-InSAR Technique for Monitoring Ground Subsidence in the Yanzhou Coal Mining Area (China)

2010 ◽  
Vol 34-35 ◽  
pp. 756-760 ◽  
Author(s):  
Zhi Yong Wang ◽  
Jin Zhi Zhang
Keyword(s):  
Coal Mining ◽  
Mining Area ◽  
Mining Subsidence ◽  
Ground Subsidence ◽  
Srtm Dem ◽  
Alos Palsar ◽  
Coal Mining Area ◽  
L Band

In this paper, it monitored ground subsidence in the coal mining area using two-pass D-InSAR technique. We obtained 9 ALOS PALSAR single-look complex (SLC) images in Yanzhou coal mining area from December 2007 to Februay 2009. Based on SAR interferometric pairs and SRTM DEM, we detected the subsided areas and got the vertical subsided quantity. We got the ground subsidence maps in different stages from 2007 to 2009. Several important subsided areas were selected and then analyzed in detail. It analyzed the general laws of mining subsidence. The results indicated that two-pass D-InSAR technique based on L-band PALSAR data and SRTM DEM is a very simple, rapid and efficient way to detect and to monitor ground subsidence in the coal mining area, even in the areas with vegetation covered.

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