Excavation in the hard, dense, less well-developed rock mass roadway, even if the excavation depth exceeds kilometers or even two kilometers, three kilometers may be self-stabilizing without support. However, if the damage occurs, it will be characterized by local peripheral rupture, sudden slag falling off or sudden convergence, and heavy as a rock burst in a large section of roadway. After the rock burst, the affected roadway may be crowded by the influx of two gangs. Death; can also be expressed as the sudden collapse of the roof or the sudden bottom of the floor.
From the laboratory bursting of specimens where uniaxial compression of rock samples occurs, rockburst is related to the following factors:
( 1 ) homogenization, cleavage is not obvious, microcracks are less, and elasticity is good. The strain recoverable when unloading near the failure is much larger than the rock with unrecoverable strain is easy to rockburst;
( 2 ) The loading system has small stiffness but good elasticity, so that when the rock is damaged, the external system can still apply excessive pressure to the rock, causing rockburst;
(3 ) Under the condition of triaxial stress, the higher the confining pressure, the greater the ductility. Once the pressure is suddenly relieved, rockburst may occur;
( 4 ) High-speed loading is easy to cause rock burst.
Rockbursts occurring in production practice are closely related to the following conditions:
1 ) Generally speaking, the greater the danger of deep rock mining, the more severe it is;
2 ) The more severe the geological tectonic stress, the greater the risk of rockburst. Therefore, in the joint part of the large fault skew, the core part of the local fold often has frequent rockburst;
3 ) The improper layout of the mining face, resulting in a highly stressful regional fulcrum pressure zone, such as an isolated or peninsular type of pillar zone, greatly promotes the occurrence of rockburst. It is extremely dangerous to excavate roadways in large pillars of extreme size, and the size of existing pillars (with built-in roadways) is extremely dangerous as they shrink as they are mined.
The analysis of rockburst problems can not be limited to the analysis of the roadway itself, but more importantly, the regional stress analysis and analysis of the regional stress conditions of the rock mass where the roadway is located. This type of analysis can be performed using elastic mechanics methods. Predicting and forecasting rockburst requires the help of experience. Using seismic, microseismic and convergence measurements to monitor the danger zone of the Department is of great benefit to perfecting the forecast.
From the laboratory bursting of specimens where uniaxial compression of rock samples occurs, rockburst is related to the following factors:
( 1 ) homogenization, cleavage is not obvious, microcracks are less, and elasticity is good. The strain recoverable when unloading near the failure is much larger than the rock with unrecoverable strain is easy to rockburst;
( 2 ) The loading system has small stiffness but good elasticity, so that when the rock is damaged, the external system can still apply excessive pressure to the rock, causing rockburst;
(3 ) Under the condition of triaxial stress, the higher the confining pressure, the greater the ductility. Once the pressure is suddenly relieved, rockburst may occur;
( 4 ) High-speed loading is easy to cause rock burst.
Rockbursts occurring in production practice are closely related to the following conditions:
1 ) Generally speaking, the greater the danger of deep rock mining, the more severe it is;
2 ) The more severe the geological tectonic stress, the greater the risk of rockburst. Therefore, in the joint part of the large fault skew, the core part of the local fold often has frequent rockburst;
3 ) The improper layout of the mining face, resulting in a highly stressful regional fulcrum pressure zone, such as an isolated or peninsular type of pillar zone, greatly promotes the occurrence of rockburst. It is extremely dangerous to excavate roadways in large pillars of extreme size, and the size of existing pillars (with built-in roadways) is extremely dangerous as they shrink as they are mined.
The analysis of rockburst problems can not be limited to the analysis of the roadway itself, but more importantly, the regional stress analysis and analysis of the regional stress conditions of the rock mass where the roadway is located. This type of analysis can be performed using elastic mechanics methods. Predicting and forecasting rockburst requires the help of experience. Using seismic, microseismic and convergence measurements to monitor the danger zone of the Department is of great benefit to perfecting the forecast.
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