非煤系地层隧道瓦斯抽放适应性评价研究

Adaptability Evaluation on Gas Drainage of Tunnels in Non-Coal Measure Strata

为评价非煤系地层隧道瓦斯能否通过抽放手段进行泄压排放,以非煤系地层瓦斯隧道为研究对象,根据非煤系地层瓦斯隧道特点,采用模糊数学综合评价法建立非煤系地层隧道瓦斯抽放适应性评价模型。从瓦斯赋存控制因素、抽放可行性控制因素和钻孔稳定性控制因素3个方面构建非煤系地层隧道瓦斯抽放适应性评价体系,选出10项基本因素作为评价指标,并采用基于层次分析法的乘积标度法对评价指标进行权重计算,构建能定量表征各评价指标因素隶属度的隶属函数,建立一级和二级模糊综合评价模型,赋予评价向量中各评语相应分值,将评价向量单值化,以判定非煤系地层隧道瓦斯抽放适应性,并结合实例进行验证分析。结果表明,南道公路马嘴隧道高瓦斯段瓦斯全断面超前抽放适应性为B级(比较适应),理论与实际应对措施吻合良好。

In order to evaluate whether tunnel gas in the non-coal measure strata can be depressurized and emitted through the gas drainage means,a gas tunnel in the non-coal measure strata is taken as the research caset.Based on the characteristics of the gas tunnel in non-coal measure strata,a comprehensive evaluation method with fuzzy mathematics is used to establish an adaptability evaluation model for tunnel gas drainage in the non-coal measure strata.An adaptability evaluation system is established for gas drainage in non-coal measure strata tunnels from three aspects:gas occurrence control factors,feasibility control factors for gas drainage and drilling stability control factors.Ten basic factors are selected as evaluation indicators.The product scale method based on the Analytic Hierarchy Process is used to calculate the weights of evaluation indicators.A membership function that can quantitatively characterize the membership degree of each evaluation indicator factor is constructed.and Class I and ClassⅡfuzzy comprehensive evaluation models are establish.This can assign corresponding scores to each remark in the evaluation vector,and achieve uniformization of the evaluation vector,thus determing the gas drainage adaptability in tunnels in the non-coal measure strata,and conducting verification and analysis in combination with instances.The results show that the adaptability of the full-section advance gas drainage in the high gas content section of the Mazui Tunnel on the Nanchuan-Daozhen Expressway is Class B(relatively adaptive),and theoretical and practical response measures are in good agreement.