Research On Gas Occurrence And Migration In Tunnel Of Cheng-De-Nan Express Way

Gas disaster is one of the major disasters during the tunnel construction. Gas disasters are the result of many factors, while their significance is different of the factors affecting the gas disaster. From the engineering angle of expectoration difficulty among positioning, qualitative and quantitative, the gas tunnels include the coal-bearing gas tunnels and non-coal gas tunnels. After the gas disaster of Yanjiaozhai coal-bearing gas tunnels in1959, the coal-bearing gas tunnel received great attention, benefiting from lessons learned from mining industry, related research is also sufficient. The Paotaishan tunnel is the first time in China revealed non-coal gas disaster which make people with unbearable pain, As non-coal gas in the tunnel with characteristics of distribution of strong randomness, low probability lead to major disasters, people tend to neglect its existence, both at home and abroad,sudden catastrophic accident has been a lot of reported.Based on the study of china’s massive paper of gas tunnel, this thesis takes Yundingshan No.l tunnel in Cheng-De-Nan Express way as the main object of study. Conducted the investigation of the Yundingshan No.1tunnel geologic background and the correlation data analysis, a comprehensive study on the gas occurrence and migration of the tunnel are made in the thesis. Study contents acquired in this thesis are mainly included as follows:(1)This paper explicates the source of tunnel area gas, geological factors on the occurrence of gas, occurrence state and the distribution of gas in the reservoir, combined with the actual situation of Yundingshan No.l tunnel, geological analysis and gas monitoring data to prediction of gas hazard in front of the tunnel are used.(2) Through analysis the geological data of the Yundingshan No.l tunnel to determine the role of pore and fracture system in gas occurrence and migration processes;(3)Discrete element method was used in the study of gas migration rules, relationship between gas emission and gas pressure or the distance of reservoir were obtained; numerical simulation method to predict the gas emission volume was made.(4)Through the study of the Yundingshan non-coal gas tunnel construction, gas hazard control measures during the gas tunnel construction were proposed.