Failure coal outburst

Numerical modelling of outbursts requires the quantification of a number of processes and factors. These include gas adsorption and desorption, coal deformation and failure, coal fragmentation, gas dynamics and transport of outburst coal (particle flow). 

After an outburst has been initiated, the outburst coal starts to deform at a high strain rate, and the fragmented coal will tend to behave as a particulate material. Depending on the gas pressure and the availability of new sources of free gas, the gas can cause further failure and fragmentation of the coal, and the expanding gas will provide a drag force to... 

With the rapid development of the national economy and the increased mining depth coal and rock dynamic disaster is increasing ay by day. In order to ensure life safety, safe, reasonable and efficient mining method are very necessary. Then the research on dynamic mechanical properties of underground rock is also very importanti l Almost all of the dynamic disaster, such as broken rock, rock burst, coal and gas outburst and other dynamic disasters had certain correlation with the rock failure under impact load and stress wave s propagation in the rocU f Because research on the dynamic mechanical properties of rock is minimal in our country, many law needs to refer to foreign datal - l, which leads to the lack of theoretical basis in China. Rock burst and other dynamic disaster tend to occur in coal seam with limestone roof Therefore, in order to effectively control the mine dynamic disasters, we must reveal its dynamic mechanical properties, thus it is very important to do the comparative study on dynamic mechanical properties of coal and limestone. 

Coal rock dynamic disasters such as rock burst and coal and gas outburst have always been major problems in coal mining. A lot of researches prove that coal and rock dynamic disaster is a result of coal and rock rupture quickly, being subject to the comprehensive action of stress and the physical chemistry inside and outside the body. Coal/rock undergoing deformation and failure emits many forms of energy, among which is electromagnetic radiation (EMR) (Wang Zhao 2013). 

Outburst process and shear stress field are shown Figure 2 respectively. According to the following two figures of numerical simulation, the results can recover the process of dynamic failure for hard coal containing gas. And the process can be divided into four sub-processes as follows stress concentration, coal rock fracture induced by ground and gas pressure, protection coal pillar was damaged by gas stress (outburst start), and crushed coal was thrown out by gas pressure (outburst devel-... 

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