scholarly journals Subsidence prediction of overburden strata and ground surface in shallow coal seam mining

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jian Cao ◽  
Qingxiang Huang ◽  
Lingfei Guo
Keyword(s):  
Coal Seam ◽  
Physical Simulation ◽  
Soil Layer ◽  
Ground Surface ◽  
In Situ Observation ◽  
Key Stratum ◽  
Shallow Coal Seam ◽  
Seam Mining ◽  
Overburden Strata

AbstractShallow coal seam with thick soil layer is widely reserved in the Jurassic Coalfield, Western China, mining-induced subsidence represents complex characteristics. Combining with physical simulation, theoretical analysis and in-situ observation, the overburden strata structure in dip direction were revealed, and the subsidence prediction models were established, based on this, the subsidence equations of overburden strata and ground surface were proposed. The results show that after shallow coal seam mining, based on the subsidence and movement characteristics, the overburden strata structure can be divided into three zones, which are "boundary pillar F-shape zone" (BPZ), "trapezoid goaf zone" (TGZ) and "coal pillar inverted trapezoidal zone" (CPZ). The subsidence of overburden strata depends on the key stratum, while the subsidence of soil layer depends on the bedrock subsidence basin, which is between the bedrock and thick soil layer. The bedrock subsidence is mainly related to mining height and bulking coefficient in TGZ, while it is mainly affected by mining height and distribution load on the key stratum in BPZ and CPZ. According to physical simulation and theoretical model, the maximum surface subsidence of No.1-2 seam mining in Ningtiaota coal mine are 1.1 m and 1.07 m respectively, which is basically consistence with the result of in-situ observation (1.2 m).

scholarly journals Subsidence Prediction of Overburden Strata and Ground Surface in Shallow Coal Seam Mining

2021 ◽  
Author(s):  
Jian Cao ◽  
Qingxiang Huang ◽  
Lingfei Guo
Keyword(s):  
Coal Seam ◽  
Physical Simulation ◽  
Soil Layer ◽  
Ground Surface ◽  
In Situ Observation ◽  
Key Stratum ◽  
Shallow Coal Seam ◽  
Seam Mining ◽  
Overburden Strata

Abstract Shallow coal seam with thick soil layer is widely reserved in the Jurassic Coalfield, Western China, mining-induced subsidence represents complex characteristics. Combining with physical simulation, theoretical analysis and in-situ observation, the overburden strata structure in dip direction were revealed, and the subsidence prediction models were established, based on this, the subsidence equations of overburden strata and ground surface were proposed. The results show that after shallow coal seam mining, based on the subsidence and movement characteristics, the overburden strata structure can be divided into three zones, which are "boundary pillar F-shape zone" (BPZ), "trapezoid goaf zone" (TGZ) and "coal pillar inverted trapezoidal zone" (CPZ). The subsidence of overburden strata depends on the key stratum, while the subsidence of soil layer depends on the bedrock subsidence basin, which is between the bedrock and thick soil layer. The bedrock subsidence is mainly related to mining height and bulking coefficient in TGZ, while it is mainly affected by mining height and distribution load on the key stratum in BPZ and CPZ. According to physical simulation and theoretical model, the maximum surface subsidence of No.1–2 seam mining in Ningtiaota coal mine are 1.1m and 1.07m respectively, which is basically consistence with the result of in-situ observation (1.2m).

scholarly journals Key Stratum Structure and Support Working Resistance of Longwall Face with Large Mining Height in the Shallow Coal Seams, China

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Qingxiang Huang ◽  
Jinlong Zhou ◽  
Jian Cao
Keyword(s):  
Coal Seam ◽  
Physical Simulation ◽  
Longwall Face ◽  
Beam Structure ◽  
Key Stratum ◽  
Immediate Roof ◽  
Large Mining Height ◽  
Shallow Coal Seam ◽  
Working Resistance ◽  
Mining Height

The fully mechanized mining with large mining height is the main method for high yield and efficient coal mining in China. The key stratum structure (KSS) is the basis of revealing the mechanism of roof weighting and determination of support working resistance of the longwall face with large mining height (LFLMH) in the shallow coal seam. The height of the caving zone at LFLMH is large, the thick immediate roof forms the “short cantilever beam” structure commonly, and the hinge layer of the overlying key stratum will move upward to the higher position. The “high position oblique step voussoir beam” structure of single-key stratum (SKS) and “oblique step voussoir beam and voussoir beam” structure of double-key stratum (DKS) in the shallow coal seam were proposed with physical simulation and Universal Distinct Element Code (UDEC). The analysis of the KSS and numerical simulation reveals the mechanism of strong roof weighting at the SKS longwall face and large-small alternate periodic weighting at the DKS longwall. It is concluded that the large static load caused by the “equivalent immediate roof (EIR)” is the basic load, and the instability load of the KSS is the additional dynamic load of support. Besides, the calculation methods of the reasonable support working resistance at LFLMH were obtained and verified with engineering applications.

scholarly journals Study on Influence Laws of Strata Behaviors for Shallow Coal Seam Mining beneath Gully Terrain

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhiqiang Wang ◽  
Jingkai Li ◽  
Chao Wu ◽  
Wenyu Lv ◽  
Jiao Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Coal Seam ◽  
Key Stratum ◽  
Fundamental Cause ◽  
Shallow Coal Seam ◽  
Mining Face ◽  
Seam Mining ◽  
Working Resistance ◽  
Strong Dynamic

The study on influence laws of strata behaviors is the basic guarantee of safety mining for shallow coal seam beneath gully terrain. Taking 3302 mining face of Zhujiamao Coal Mine as the engineering background, the laws of strata behaviors for shallow coal seam mining beneath gully terrain are studied by field detection, theoretical analysis, and numerical simulation. The strata pressure observation and the hydraulic support working resistance show that the dynamic strata behaviors appear violently during mining beneath the gully bottom. The theoretical analysis shows that the rotation and breaking of key stratum beneath gully bottom under nonuniform load is the fundamental cause of strong dynamic strata behaviors. The numerical simulation of overburden movement and fissure development characteristics shows that the strata behaviors beneath the gully bottom are stronger than the strata behaviors beneath other areas. Additionally, according to the laws of dynamic strata behaviors, the safety measures for mining beneath gully bottom are put forward.

Numerical Simulation of Underground Pressure in Mining High-Inclined Coal-Seam with Analysis of Material Properties in Mine Dongbaowei

2013 ◽  
Vol 644 ◽  
pp. 382-386 ◽  
Author(s):  
Ming Ming Wen
Keyword(s):  
Coal Seam ◽  
In Situ Observation ◽  
Coal Seams ◽  
Relevant Model ◽  
Roof Caving ◽  
Deformation Feature ◽  
Working Face ◽  
Strata Behavior ◽  
Surrounding Rock Stress

The FLAC software is used in establishing a relevant model to study the strata behavior of fully mechanized working face of steep coal seams. Using this model, we have simulated the roof caving characteristic and the stress distribution of surrounding rocks and analyzed the deformation feature of the surrounding rocks in the working face end. Based on the in-situ observation about the fully mechanized working face, we have obtained the surrounding rock stress and the strata behavior of steep coal seam and proposed some countermeasures aiming at these problems.

Detecting the landslide vulnerability in the epicentre of Wenchuan Earthquake via SBAS-InSAR method

2020 ◽  
Author(s):  
Wenjiang Zhang
Keyword(s):  
Wenchuan Earthquake ◽  
Soil Layer ◽  
In Situ Monitoring ◽  
Ground Subsidence ◽  
In Situ Observation ◽  
Interferometric Synthetic Aperture Radar ◽  
Multi Temporal ◽  
Sbas Insar ◽  
River Valleys

<p>Valleys in the epicentre of Wenchuan Earthquake (Sichuan Province, China) are severely subjected to landside risks partially due to the persistent influences of the serious earthquake in 2008. Without enough regionally in-situ monitoring measures, the method of multi-temporal, differential interferometric synthetic aperture radar (D-InSAR) provides an efficient to monitor the surface subsidence and thus the landslide vulnerability. In this study, we used the Sentinel Satellite Images (2015-2018) to extract the subsidence information along river valleys near the Wenchuan Earth epicentre, which was well validated by the in-situ observation of one GPS station (RSME=1.6 cm, p<0.01). Our results showed the persistent ground subsidence (1.5 mm yr<sup>-1</sup>, p<0.01) at many places, which was also related to terrain aspect besides to the well-proved conditions of slope, vegetation cover and soil layer. This fact that implied the terrain aspect should be taken into accounts in landside vulnerability analyses, because precipitation is locally more abundant in windward places. Results emphasized the higher vulnerability of landslide in summer, which could be attributed to more precipitation during summer in the study area. Our study extracted over 100-km valleys (and especially ~50 places) with high landslide vulnerability (subsidence rate > 1.20 mm yr<sup>-1</sup>), which should be paid high-prior careful attentions so as to avoid potential geological disasters.</p>

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