Mechanical properties of oil shale-coal composite samples

Chen, Shaojie; Yin, Dawei; Ning, Jianguo; Wang, Feng; Zhao, Zenghui

doi:10.1016/j.ijrmms.2019.104120

Cited by 92 publications

(60 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[22][23][24] In the process of mining engineering, a rock mass is subjected to continuous loading and unloading under polyaxial stress states. [25][26][27][28][29][30] The stress-strain characteristics of the rock mass showed different mechanical responses with changes in the mining sequence. 31,32 Gong et al 33 adopted an analytic hierarchy process (AHP) with a fuzzy comprehensive evaluation method to study the underground mining method sequence.…”

Section: Introductionmentioning

confidence: 99%

Modeling study on the influence of the strip filling mining sequence on mining‐induced failure

Ning

Wang

Pan

et al. 2020

Energy Science & Engineering

Self Cite

View full text Add to dashboard Cite

The strip filling mining method can solve the problems related to mining under structures, under aquifers, and under infrastructure (3U coal seams), while the reasonable selection of the mining and filling sequence still requires further investigation. The current study was conducted to investigate the stress and surface subsidence of a filling body (or coal pillar) under two filling sequences through theoretical analysis, similar simulation tests, and numerical simulations. To achieve optimal filling materials for the Liudong Coal Mine, a low-strength similar paste filling material composed of fly ash, gypsum, and sand was developed. The relationships between the strength and the cement ratio and between the strength and the sand-binder ratio were discussed. Similar simulation tests showed that mining scheme 1 (mining before filling) could lead to the formation of an isolated island coal pillar in the mining process, mining scheme 2 (filling before mining) had less influence on surface subsidence, and the stress on the filling body was smaller for scheme 2 than for scheme 1. The distributions of the stress and plastic zone in the two different mining and filling sequences were obtained through numerical simulations. The method of first filling and then mining could greatly reduce the stress concentration and plastic zone during the mining process. In summary, mining scheme 2 (filling before mining) can avoid the formation of isolated island coal pillars in the process of mining, and without considering other factors, scheme 2 should be adopted as much as possible.

show abstract

Section: Introductionmentioning

confidence: 99%

Modeling study on the influence of the strip filling mining sequence on mining‐induced failure

Ning

Wang

Pan

et al. 2020

Energy Science & Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…Monitoring and evaluation of the anchoring performance is an important basis to judge the effectiveness of bolts, and hence, to ascertain the safety of the underground coal mine roadways. The stability of underground structures is closely related to the type and properties of rock . Rocks have complex mechanical properties, laboratory experiments alone are not adequate to study their properties and some in situ measurements are necessary .…”

Section: Introductionmentioning

confidence: 99%

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

Liu

Chai

Chen

et al. 2020

Energy Science & Engineering

Self Cite

View full text Add to dashboard Cite

Bolt is an important connection in underground construction and monitoring its stress characteristics is essential to evaluate the effectiveness of bolt. The strain information collected along a rock bolt reveals the long-term movement characteristics of rock mass, which greatly helps toward disaster prevention and risk warning.Grooving on the surface of a bolt and embedding an optical fiber is one of the main methods for monitoring the anchorage performance and stress distribution around the bolt in underground engineering. In this study, Pulse Pre-Pumped Brillouin Optical Time Domain Analysis (PPP-BOTDA) technology is used to evaluate the stress, axial force, and shear stress distribution of the bolt under tensile load for different types (grooved and nongrooved) of bolts embedded in concrete with resin as anchoring agent. The results show that the PPP-BOTDA sensor can be used to monitor the stress state of the bolt embedded in concrete with resin as anchoring agent when the bolt is subjected to a tensile force. However, the apparent stress value measured in this way is not the actual stress value of the bolt, but is an increased value caused due to the groove. The closer to the exposed end of the bolt, the greater is the deviation between the apparent stress value and the actual stress value of the bolt. Based on the monitoring results from this experimental study, a stress reduction calculation method is proposed, which can change the measured value into the actual stress of the bolt. K E Y W O R D Saxial force, bolt, PPP-BOTDA technology, pullout test, shear stress 2012 |

show abstract

“…e strength of sandstone is far greater than that of coal in the composite sample. erefore, in a composite sample, the coal with the lower strength determines the structural strength of the composite sample [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In addition, the instability and failure of the composite samples was caused by the failure of the coal.…”

Section: Strength Characteristics Of the Composite Samplesmentioning

confidence: 99%

“…e area being mined in a coal-mining operation is essentially a composite structure consisting of coal seam and surrounding rock strata. e instability and failure of the composite structure can cause many hazards during coal mining, such as rock bursts and coal bumps, resulting in potential safety hazards to coal production [1][2][3][4][5][6]. However, the coal seam generally contains many more pre-existing defects than the rock stratum, which seriously affects the stability of the composite structure [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…A lot of investigations have been performed in the past on the mechanical behaviour of composite structures composed of coal seam and surrounding rock strata [1][2][3][4][5][6][7][9][10][11][12][13][14][15][16][17][18][19][20][21]. In previous laboratory tests and numerical simulations, the composite structure was generally simplified as a composite sample of rock and coal with a bonded or frictional interface in order to study its mechanical behaviour [1][2][3][4][5][6][7][9][10][11][12][13][14][15][16][17][18][19][20][21]. e effects of rock strength and rock to coal height ratio on the strength and failure characteristics of rock-coal composite samples were studied by Liu et al [2] and Chen et al [11], respectively.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Experimental Study of the Uniaxial Failure Behaviour of Rock‐Coal Composite Samples with Pre‐existing Cracks in the Coal

Chen

Yao

Yin

et al. 2019

Advances in Civil Engineering

Self Cite

View full text Add to dashboard Cite

Many hazards encountered during coal mining can be caused by the instability and failure of the composite structure of the coal seam and the surrounding rock strata. The defects present in the coal affect the structural stability of the composite structure. In this study, uniaxial compression tests were conducted on sandstone-coal composite samples with pre-existing cracks in the coal, combined with tests performed with an acoustic emission (AE) device and a digital video camera. The strength, macrofailure initiation (MFI), and failure characteristics of composite samples, as influenced by the coal’s pre-existing cracks, were analysed. The coal’s pre-existing cracks were shown to reduce the strength, promote the occurrence of MFI, and affect the failure characteristics of the samples. Vertical penetration cracks had much more pronounced effects on strength and MFI occurrence, especially vertical penetration cracks that penetrated through the centre of the coal. Horizontal penetration cracks had a much reduced effect on strength and MFI occurrence. The MFI caused a step shape in the stress-strain curve accompanied with a peak energy index signal and occurred around the original coal cracks. The MFI models predominantly exhibited crack initiation from the pre-existing coal cracks and surface spalling caused by crack propagation. The intact composite sample failure presented as an instantaneous failure, whereas the composite samples containing the pre-existing cracks showed a progressive failure. The failures of composite samples occurred predominantly within the coal and displayed an X-typed shear failure accompanied by a small splitting failure. Both the coal and sandstone were destroyed in the composite sample with vertical penetration cracks through the centre of the coal. Failure of the coal occurred through a splitting failure accompanied by a small X-typed shear failure, while the sandstone showed a splitting failure induced by crack propagation in the coal.

show abstract

Mechanical properties of oil shale-coal composite samples

Cited by 92 publications

References 35 publications

Modeling study on the influence of the strip filling mining sequence on mining‐induced failure

Modeling study on the influence of the strip filling mining sequence on mining‐induced failure

Monitoring and correction of the stress in an anchor bolt based on Pulse Pre‐Pumped Brillouin Optical Time Domain Analysis

An Experimental Study of the Uniaxial Failure Behaviour of Rock‐Coal Composite Samples with Pre‐existing Cracks in the Coal

Contact Info

Product

Resources

About