Abstract:

The components, properties and damages of major harmful gases in underground caverns, as well as accidents caused by harmful gases, are presented. The causes, occurring conditions and damages modes of the harmful gases are analyzed and summarized and countermeasures are proposed. Regarding the detection of the harmful gases, oxygen and other inflammable and explosioncausing gases should be detected before toxic gases are detected. Regarding the prevention and control of the harmful gases, areas with harmful gases should be avoided as far as possible and countermeasures, such as gas sealing, gas releasing, ventilation improving, using proper explosives and adopting proper drilling and blasting technologies shall be taken so as to avoid accidents caused by harmful gases.

Key words: hydropower works, harmful gas, LEL (Lower Explosive Limit)