Study On The Gas Emission Law And Its Control Measures In The Shale Section Of Highway Tunnel

With the development of western and One Belt And One Road and other strategies,China’s tunnel construction has entered a period of rapid development.However,safety accidents occur frequently during the construction of tunnels,especially in many accident disasters,the gas disasters tend to have more serious consequences.Therefore,many domestic scholars have conducted a lot of research and achieved fruitful results.However,most of these studies are aimed at coal strata,and the research on non-coal strata,especially shale formation,is very limited.At the same time,compared with coal-based strata,the possibility of gas accidents in non-coal strata is more likely,resulting in heavier casualties.Then,the article based on the engineering background of shale gas tunnel section,through the information query,such as theoretical analysis,numerical simulation method,the gas source,migration characteristics,shale section of the law and gas control and so on has carried on the related research,and obtained the following results:(1)on the basis of previous studies,the main sources and forms of gas in shale lot are analyzed,By means of numerical simulation,the migration of gas in surrounding rock was studied.(2)introduced the layout of the gas monitoring system in the horse’s mouth tunnel,and established the gas emission database of different sections of the tunnel after excavation and the different time of the same section;Based on this,the distribution of gas emission in different positions in the tunnel of shale lot is studied,and the gas emission law of the same section at different times is studied.(3)The prediction method of gas emission in the tunnel of shale lot is explored.The application of exponential smoothing in tunnel gas prediction is discussed.At the same time,the smooth model of different times is discussed.Finally,the reliability of the model is verified by the monitoring data of the horse mouth tunnel.The results show that the model can predict the gas emission in the tunnel effectively.(4)Summarized the gas treatment measures of shale section.Points out that the gas tunnel control measures including advance geological forecast,drilling drainage,grouting seal,equipment modification,strengthening ventilation,inside lining of adding gas tightness material and moisture separation device,etc.At the same time,it is pointed out that according to the geological conditions of the surrounding rock of the tunneling area,the combination method should be adopted to control the gas.