RESEARCH ON GEOLOGICAL CHARACTERISTICS OF ZIPINGPU GAS TUNNEL IN SICHUAN PROVINCE CHINA

Gases are common constituents of the underground environment, along with soils, rocks, and water. It is widely believed that gases in underground originate from the bacterial decomposition and thermal decomposition of organic and inorganic compounds, and geochemical reactions. Gases are usually widely dispersed in low concentrations, but under some geologic conditions are abundant. Gas can be a hazard to construction of underground civil works such as tunnels and underground chambers.

There were a extrmely immense mashgas explosion accident happening in the process of tunnel-construction of ZiPingPu, part of the expressway from DuJiangYan to WenChuan in SiChuan Province, at 2:00pm or so on December 22,2005,leading to the death of 44 people, injury of 11 ,a direct economy loss up to 20,350,000 Yuan.During the explosion, a worker was threw away to as far as 168m beyond by the power of high pressure striking-wave produced by the explosion and "barrel effect".Besides, numbers of vehicles of disparate use were impacted so heavily that they were almost totally transfigured, a formworking jumbo weighing approximately 70t were also pushed 47m foward by the striking-wave along a straight line ,severely transformed.

Gas tunnels widely distributed in China’s gas-rich area，research on the geological characteristics of gas tunnel has great scientific significance. This paper focuses on the gas monitoring data, coal seam, lithology and structure to clarify the geological characteristics of ZiPingPu gas tunnel.