石门揭煤工作面煤与瓦斯突出预测的理论分析

目前,我国石门揭煤工作面突出事故仍时有发生。为了研究石门揭煤工作面煤与瓦斯突出(以下简称"突出")预测问题,首先,根据工作经验指出我国《防治煤与瓦斯突出规定》中2种预测方法(综合指标法、钻屑瓦斯解吸指标法)存在的不足,即预测指标缺乏理论依据、临界值往往难以通过试验考察确定;其次,建立了石门揭煤工作面突出预测的物理模型,认为突出主要是爆破卸压增渗与瓦斯渗流产生的剪应力达到了煤体的剪切强度所致(突出的必要条件而非充要条件);第三,采用变分法求解强非线性一维平面瓦斯渗流偏微分方程,获得包括非线性特性的自模拟解(近似解析解);最后,利用自模拟解等建立了石门揭煤工作面突出预测的临界条件,得到了瓦斯压力的临界值p0max与煤的坚固性系数f的平方成正比的结论。介绍了俄罗斯现行防突指南中的临界条件(p0max1.4f2)及有关情况,建议作为综合指标法等的辅助指标用于石门揭煤工作面突出预测,也可供斜井、立井揭煤工作面突出预测参考。

Theoretical prediction of the coal and gas outbursts at Shimen open-pit mining faces

The present paper is intended to focus itself on how to predict the coal and gas outbursts at Shimen uncovering coal faces (hereinafter referred to as "the coal and gas outburst") of underground coal mines.For the time being,it is often the case that there took place outbursts of coal and gas from time to time at the said uncovering coal faces.To deal with the problem,first of all,it is necessary to point it out that it is actually quite difficult to determine the critical signs and indicators on how to predict can prevent such outburst events,rather,most of such findings of the indicators are merely done based on the working experience of the experts or the experienced workers.Therefore,the two principal forecast and prediction methods (known as the comprehensive index method and the gas desorption index method of drilling cuttings) can be said with serious drawbacks of enough qualified regulations on how to predict such outbursts and the corresponding measures on how to deal with the said ominous outburst risks from the highest state administrative departments on the safety production supervision,i.e.the criteria for the theoretical deduction and the disaster risk preventive and precaution policy and measure foundations.And,the next,we have established a physical schematic model for predicting the coal and gas outbursts,whose chief purpose is to clarify and confirm the coalmine outbursts as merely the results both of the gas flow and the increment of the permeability of the coal deposits near the uncovering coal face by blasting,whereas the shear stress caused by the gas seepage tends to develop and expand its shear strength (necessary and not sufficient conditions for outbursts).And,thirdly,we have managed to solve the nonlinear partial differential equation of one-dimensional plane gas seepage approximately with the variational method,and work out the self-simulated solution including the nonlinear characteristic features.And,finally,we have laid out the theoretical criteria for forecasting the outburst liabilities via the self-simulated solution,etc.Furthermore,it has also been found that the critical signs of the gas pressure,i.e.Pomax,should be made in a positive proportion to the square of the coefficient of the coal strength,f.And,consequently,we have made a brief introduction of the forecasting criteria for the said coal and gas outbursts in reference to the Russian experience (P0max ＜ 1.4f2) as well as the related signs and predictive judgments recommended to be used for forecasting such coal-mining outbursts as a supplementary method to the Comprehensive Index Method at home.Thus,it can be seen that the conclusions gained in this paper are in a position to help to make the coalmining outburst forecast and prediction of the inclined shaft and the shaft uncovering coal workfaces.