含瓦斯突出隧道破坏机理及其控制探讨

Failure Mechanism and Control Measures for Gas Bursts in Gas Tunnels

瓦斯是隧道施工地质灾害之一,瓦斯突出给工程施工造成的危害性极大。文章结合某铁路瓦斯高风险隧道工程施工实例,对隧道瓦斯突出的破坏机理进行了研究,从超前地质预测预报、瓦斯监测、施工通风、揭煤方式等方面探讨了隧道施工瓦斯突出的预防、控制和安全措施。结果表明:(1)瓦斯突出是一种复杂的动力现象,是突出的煤体、岩石、瓦斯和应力场等多种因素作用的结果,煤岩体所积存的弹性应变能和瓦斯内能是瓦斯突出发生的能量,地应力突变和掘进施工的扰动是激发瓦斯突出的诱因;(2)铁路隧道瓦斯突出主要是掌子面存在薄弱点或面,在掘进施工的扰动下,如果预防措施不到位,容易产生瓦斯突出;(3)以超前水平钻孔、加深炮孔探测和瓦斯测定技术为主,各种物探方法相结合的综合超前地质预测预报系统,是预防瓦斯突出的重要手段;(4)采用瓦斯排放、揭煤、通风、结构处理等技术措施,结合安全标准化管理系统,能够有效规避施工安全风险。

Considering that gas bursts are very detrimental to tunnel construction, and using a railway tunnel with such a risk as an example, this paper discusses the failure mechanism and relevant prevention and control measures from the aspects of advance geological prediction, gas monitoring, construction ventilation and coal disclosing technology. Results show that： 1） gas burst—the result of multiple factors, including of the outburst of coal, rock, gas and stress field—is a complex dynamic phenomena, for which the elastic strain energy of the coal and rock and the internal energy of the gas are the bursting energies and the geostress mutation and construction disturbance are the incentives; 2） gas bursts are easily induced at the weak point or surface of the working face,especially during construction disturbances with poor prevention; 3） a comprehensive advance geological prediction system, dominated by advance horizontal drilling, deepened hole detection and gas measurement and various physical exploration methods, is an important means to prevent gas bursts; and 4） with the help of a safety standard management system, construction risks can be effectively avoided by adopting technical measures like gas emission, coal disclosing, construction ventilation and structural treatment.