Numerical Simulation of the Fluid–Solid Coupling Process During the Failure of a Fractured Coal–Rock Mass Based on the Regional Geostress

Shan, Pengfei; Lai, Xingping

doi:10.1007/s11242-018-1110-6

Cited by 51 publications

(36 citation statements)

References 11 publications

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“…Bolts are vital to the advancement of underground excavation in engineering work, such as subway tunnels and coal mines, as they connect broken rock mass, enhance the stability of underground coal mine roadways and surrounding rock, and reduce the occurrence of rock burst . In countries such as China where huge amount of coal is mined, problems of roof falling (roof collapse), land subsidence, and collapse result in a series of secondary disasters, directly threatening production, and life safety . 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.…”

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

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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 |

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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

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“…This indicated that the most forceful MS event was located in the northeast of the T9 borehole at a distance of 51.2 m, and the other larger-energy (13910 J) MS events occurred around that largest one ( Figure 6A). 45 The micro natural fractures and coal or rock cleats might slip to produce MS activities. It can be found that MS events did not occur from the near to the distant but disorderly when compared MS location with the time scale.…”

Section: Ms Occurrencementioning

confidence: 99%

“…When HF disturbed the in situ stress around the borehole, the mechanical balance was broken. 45 The micro natural fractures and coal or rock cleats might slip to produce MS activities. Figure 7 showed that a large number of MS events occurred on the roof and floor, indicating that both the coal seam and the roof-floor had been destroyed during the HF process.…”

Section: Ms Occurrencementioning

confidence: 99%

Underground microseismic monitoring of a hydraulic fracturing operation for CBM reservoirs in a coal mine

Jiang

et al. 2019

Energy Science & Engineering

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Hydraulic fracturing can evidently improve the coalbed methane production in underground coal mines, but it is difficult to delimit the stimulated area accurately. In order to evaluate the stimulated area, microseismic (MS) monitoring technique is proposed to investigate the seismic responses of the induced fractures of hydraulic fracturing. Three coal seams were targeted to be treated in a coal mine. An array of geophones was set along the underground roadway to detect the MS signals caused by HF. In order to verify the result of MS monitoring, water content of each coal seam has been measured before and after HF treatment. The results showed that a series of MS events were detected during the entire HF process, and a sharp MS event usually occurred during the first hour of HF process. The energy of the sharp MS event had higher magnitude than others. The MS distribution exhibited complex morphological features. The directionless MS response was distributed over a radius of less than 40 m but tended to be significantly conjugated with a radius of more than 40 m. HF could stimulate both the coal seam and the rock layers nearby. The achievable stimulated area in the coal seam was determined to be 50 m × 50 m according to the MS density and water content. The stimulated area in terms of MS density was easily found to be broader than the area of water direct intrusion. The present study indicated that MS monitoring technique could potentially be used for evaluation of HF in underground coal mine.

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“…FLAC3D (the fast lagrangian analysis of continua in 3-dimensions software) is used to simulate the stress state of rock burst roadway, and the results show that the stress concentration area caused by excavation is the place where rock burst occurs frequently [22]. Through numerical calculation and computed tomography, the change characteristics of regional geostress and fracture development are inverted, and the accuracy of the inversion method is verified based on the field monitoring data [23,24].…”

Section: Introductionmentioning

confidence: 99%

Study on Rule of Overburden Failure and Rock Burst Hazard under Repeated Mining in Fully Mechanized Top-Coal Caving Face with Hard Roof

et al. 2019

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The dynamic disasters caused by the failure of hard roof in the process of mining coal seriously affect the safe production in coal mines. Based on the W1123 mining coal working face of Kuangou coal mine, the physical similar material simulation experiment and acoustic emission (AE) monitoring method are used to study the failure law and AE characteristics of overburden in the process of coal mining. The stress evolution law is revealed through numerical simulation, the dangerous areas and rock burst hazard under the repeated mining with hard roof are studied combined with microseismic monitoring on site. The results show that the energy of W1123 working face released by the overburden damage under B4-1 solid coal is higher than that of the gob, and the peak value of the AE energy appears near the W1145 open-off cut. Through the statistics of the AE data, the large energy rate of AE event is defined, and the AE events with large energy rate appear in the scale of 82.4–231.2 cm within the model. This area is shown as a stress superposition area according to the numerical simulation. On the basis of comparing with the characteristics of energy distribution in the field, it is considered that the main control factors of rock burst in this area are hard roof of the working face and the stress concentration caused by the repeated mining. It provides a scientific guidance for the prevention and control measures of rock burst in this type of mining condition.

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Numerical Simulation of the Fluid–Solid Coupling Process During the Failure of a Fractured Coal–Rock Mass Based on the Regional Geostress

Cited by 51 publications

References 11 publications

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

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

Underground microseismic monitoring of a hydraulic fracturing operation for CBM reservoirs in a coal mine

Study on Rule of Overburden Failure and Rock Burst Hazard under Repeated Mining in Fully Mechanized Top-Coal Caving Face with Hard Roof

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