scholarly journals Investigation on fracture models and ground pressure distribution of thick hard rock strata including weak interlayer

2021 ◽  
Author(s):  
Meilu Yu ◽  
Jianping Zuo ◽  
Yunjiang Sun ◽  
Changning Mi ◽  
Zhengdai Li
Keyword(s):  
Pressure Distribution ◽  
Hard Rock ◽  
Ground Pressure ◽  
Fracture Models ◽  
Weak Interlayer ◽  
Rock Strata

scholarly journals Controlling mine pressure by subjecting high-level hard rock strata to ground fracturing

2021 ◽  
Author(s):  
Rui Gao ◽  
Tiejun Kuang ◽  
Yanqun Zhang ◽  
Wenyang Zhang ◽  
Chunyang Quan
Keyword(s):  
Energy Release ◽  
Physical Simulation ◽  
Hard Rock ◽  
Structural Characteristics ◽  
Effective Control ◽  
Mine Pressure ◽  
Control Effect ◽  
Propagation Length ◽  
Ground Pressure ◽  
High Level

AbstractWhen mining extra-thick coal seams, the main cause of strong ground pressure are the high-level thick and hard strata, but as yet there is no active and effective control technology. This paper proposes the method of subjecting hard roofs to ground fracturing, and physical simulation is used to study the control effect of ground fracturing on the strata structure and energy release. The results show that ground fracturing changes the structural characteristics of the strata and reduces the energy release intensity and the spatial extent of overburden movement, thereby exerting significant control on the ground pressure. The Datong mining area in China is selected as the engineering background. An engineering test was conducted on site by ground horizontal well fracturing, and a 20-m-thick hard rock layer located 110 m vertically above the coal seam was targeted as the fracturing layer. On-site microseismic monitoring shows that the crack propagation length is up to 216 m and the height is up to 50 m. On-site mine pressure monitoring shows that (1) the roadway deformation is reduced to 100 mm, (2) the periodic weighting characteristics of the hydraulic supports are not obvious, and (3) the ground pressure in the working face is controlled significantly, thereby showing that the ground fracturing is successful. Ground fracturing changed the breaking characteristics of the high-level hard strata, thereby helping to ameliorate the stress concentration in the stope and providing an effective control approach for hard rock.

The foot-ground pressure distribution following triple arthrodesis

1981 ◽  
Vol 98 (4) ◽  
pp. 263-269 ◽  
Author(s):  
Haim Stein ◽  
Ariel Simkin ◽  
Keenan Joseph
Keyword(s):  
Pressure Distribution ◽  
Triple Arthrodesis ◽  
Ground Pressure

scholarly journals Mechanism and Prevention and Control of Mine Earthquake in Thick and Hard Rock Strata considering the Horizontal Stress Evolution of Stope

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Ming Zhang ◽  
Xuelong Hu ◽  
Hongtao Huang ◽  
Guangyao Chen ◽  
Shan Gao ◽  
...  
Keyword(s):  
Hard Rock ◽  
Design Method ◽  
Horizontal Stress ◽  
Prevention Measures ◽  
Stress Concentrations ◽  
Estimation Model ◽  
Working Face ◽  
Mining Design ◽  
And Control ◽  
Rock Strata

This study investigated the mechanism, prevention measures, and control methods for earthquake disasters typically occurring in mines with thick and hard rock strata. A mine stope with large faults and thick hard rock strata in Hebei Province was taken as the background study object. Then, theoretical analysis and numerical simulation methods were adopted in conjunction with field monitoring to explore how horizontal stress evolves in the thick and hard hanging roofs of such mines, potentially leading to mining earthquakes. Then, based on the obtained results, a mining design method was proposed to reduce the horizontal stress levels of earthquake mitigation. The results showed that, under the control of large faults, semiopen and semiclosed stopes with thick hard rock strata are formed, which cause influentially pressurized and depressurized zones during the evolution of the overburden movements and horizontal stress. It was determined that the stress concentrations mainly originated from the release and transfer of horizontal stress during the rock fractures and movements in the roof areas, which were calculated using a theoretical estimation model. The horizontal stress concentrations formed “counter torques” at both ends of the thick and hard strata, which prevented the support ending due to tensile failures. As a result, the limit spans were increased. This study proposed a mining strategy of using narrow working faces, strip mining processes, and reasonable mining speeds, which could effectively reduce horizontal stress concentrations and consequently prevent and control mining earthquakes. This study’s research results were successfully applied to the mining practices in working face 16103.

Rock Floor Pressure Analysis of Hydraulic Support

2013 ◽  
Vol 389 ◽  
pp. 1058-1061
Author(s):  
Zhi Wang ◽  
He Ping Ni
Keyword(s):  
Pressure Distribution ◽  
Hard Rock ◽  
Beam Theory ◽  
Base Plate ◽  
Maximum Pressure ◽  
Distribution Law ◽  
Hydraulic Support ◽  
Calculation Results ◽  
Elastic Foundation Beam ◽  
Selection Of

According to the plastic floor assumptions, the floor pressure distribution law was obtained based on plane force analysis of hydraulic support. In order to compare the floor pressure on the elastic floor and plastic floor, Elastic foundation beam theory was introduced to the calculation of the floor pressure. The results show that the pressure distribution is changed with the changing of the subgrade coefficient. The pressure is trapezoidal distributed when the floor is relatively soft and the plastic floor assumptions is reasonable. In a relatively hard rock floor, the maximum pressure appear near the column nest which is very different from the calculation results based on the plastic base plate assumptions. It is suggested that the soft and the hard rock floor should be treated differently during the design and selection of hydraulic support. .

scholarly journals DEM numerical investigation on the effect of back rake angle of PDC bit in drilling hard rock strata

2021 ◽  
Vol 861 (4) ◽  
pp. 042107
Author(s):  
Yu Zhou ◽  
Qinyuan Liang ◽  
Qiongqiong Tang ◽  
Bo Li
Keyword(s):  
Numerical Investigation ◽  
Hard Rock ◽  
Rake Angle ◽  
Pdc Bit ◽  
Rock Strata

Square-form structure failure model of mining-affected hard rock strata: theoretical derivation, application and verification

2016 ◽  
Vol 75 (16) ◽  
Author(s):  
Chao Xu ◽  
Liang Yuan ◽  
Yuanping Cheng ◽  
Kai Wang ◽  
Aitao Zhou ◽  
...  
Keyword(s):  
Hard Rock ◽  
Failure Model ◽  
Theoretical Derivation ◽  
Rock Strata

scholarly journals Theoretical Analysis and Numerical Simulation of the Graben Fault Instability Mechanism

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qihua Ma ◽  
Shiwei Niu ◽  
Huaguo Wang ◽  
Weixiang Ma ◽  
Lihui Chi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Rock Burst ◽  
Recovery Process ◽  
Instability Mechanism ◽  
Geological Structures ◽  
Ground Pressure ◽  
Working Face ◽  
Shear Beam ◽  
Rock Strata ◽  
Elastic Shear

The rock burst caused by geological structures is abrupt and destructive, and the special structure of a graben fault decides the uniqueness of mine ground pressure in the mining process. By simplifying the graben fault structure, the evolution law of roof stress during the recovery process was studied based on the theory of the elastic shear beam. The change laws of stress field and displacement nearby the fault during the advancement process of the working face were explored through a numerical simulation, and the instability mechanism and laws of rock strata nearby this graben fault were revealed. This study will be of great significance for preventing and controlling the rock burst in the graben fault.

Parametric analysis of the dynamic foot to ground pressure distribution after fracture of the os calcis

1990 ◽  
Vol 23 (4) ◽  
pp. 372
Author(s):  
Th. Mittlmeier ◽  
G. Lob ◽  
W. Mutschler ◽  
G. Bauer
Keyword(s):  
Pressure Distribution ◽  
Parametric Analysis ◽  
Os Calcis ◽  
Ground Pressure
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