煤与瓦斯突出的一维流动模型和启动判据

本文将煤与瓦斯突出这一现象和因素模化,建立了研究机理的一维流动模型,给出了基本方程和突出基本准则——破碎起动准则。在这理想模型中,开挖前的围压作为煤体受载因素影响破碎起动从而影响流场,流场与应力场则解耦,可独立地研究流场,研究瓦斯渗流,煤的破碎起动及随后的两相流与纯气相流。 掘进是外加扰动,使渗流相对加剧,是启动突出的基本因素。讨论恒速掘进下的渗流过程,从渐近解——恒稳渗出解给出启动判据,分别表示成:可能条件——地应力条件;孕育条件——掘进条件或瓦斯条件;触发条件——渗出速度条件。

ONE-DIMENSIONAL FLOW MODEL FOR COAL-GAS OUTBURSTS AND INITIATION CRITERION

To analyse the mechanism of coal-gas outbursts, a one-dimensional flow model is established. A break-start criterion of coal, as a basic criterion of outbursts, is given. In this ideal model, the tectonic pressure before excavation, as a load on coal mass, affects break-start and then the flow field. The flow field is decoupled with the stress field of coal, so that the gas seepage, the break-start of coal and the consequent two-phase flow, and pure gas flow, can be analysed independently of the stress field.Tunnelling, the external disturbance that intensifies the seepage flow relatively, is an essential factor to initiate outbursts. Steady tunnelling makes the seepage tend to become steady. From the asymptotic solution-steady seepage solution, the initiation criterion is obtained. This criterion includes three conditions: possibility condition, it is a tectonic pressure condition; incubation condition, a tunnelling or gas condition; and triggering condition, a seepage velocity condition.