This paper discribes a one-dimensional flow model to explain the basic mechanism of coal-gas outbursts.A break-start criterion of coal,as the elementary outburst criterion,is given approximately.In this ideal model,th...This paper discribes a one-dimensional flow model to explain the basic mechanism of coal-gas outbursts.A break-start criterion of coal,as the elementary outburst criterion,is given approximately.In this ideal model,the tectonic pressure before excavation,as a load on coal body,affects the break-start and then the flow field.The flow field is decoupled with the stress field,so that the gas seepage through unbroken coal body,break-start and consequent two-phase flow,and pure gas flow can be analysed independently of the stress field. The tunnelling,an external disturbance that makes the seepage intensify relatively,is an essential factor for initiating outburst.Under steady tunnelling,seepage ought to tend to be steadily progressive.From its asymptotic solution initiation criterion is obtained.This is described by three conditions,possibility condi- tion—tectonic pressure condition,incubation condition—tunnelling or gas condition and triggering condi- tion—seepage velocity condition.展开更多
基金The project supported by the National Natural Science Foundation of China
文摘This paper discribes a one-dimensional flow model to explain the basic mechanism of coal-gas outbursts.A break-start criterion of coal,as the elementary outburst criterion,is given approximately.In this ideal model,the tectonic pressure before excavation,as a load on coal body,affects the break-start and then the flow field.The flow field is decoupled with the stress field,so that the gas seepage through unbroken coal body,break-start and consequent two-phase flow,and pure gas flow can be analysed independently of the stress field. The tunnelling,an external disturbance that makes the seepage intensify relatively,is an essential factor for initiating outburst.Under steady tunnelling,seepage ought to tend to be steadily progressive.From its asymptotic solution initiation criterion is obtained.This is described by three conditions,possibility condi- tion—tectonic pressure condition,incubation condition—tunnelling or gas condition and triggering condi- tion—seepage velocity condition.
