关键词: 混合井, 酸性水, 井筒稳定性, 防治技术

Abstract: In view of the current situation of frequent corrosion of acid groundwater in mine shafts and roadways，taking a mixed well of a sulfur gold mine in Anhui Province as the engineering background，the current situation of acid water corrosion in mixed wells is investigated by means of field investigation，theo⁃ retical analysis and numerical simulation. The weakening mechanism of concrete strength under acid corro⁃ sion conditions is revealed，the stability of shaft under acid corrosion conditions is studied，and the preven⁃ tion and control countermeasures are put forward. The results show that the acid gushing water in the well⁃ bore comes from the accumulated water in the old goaf of the surrounding sulfide mine. The residual sulfide minerals in the goaf interact with oxygen and water to generate acid water，which is laterally supplied to the wellbore through water sources such as rock fissures. There are abnormal changes in rock movement，stress and plastic zone distribution within -168 ~ -270 m and -495 ~ -575 m in the wellbore，with poor stability and great potential safety hazards. In order to enhance the stability of the wellbore and ensure the production safety of the wellbore，the comprehensive prevention and control measures of reducing acid water gushing， increasing the comprehensive strength of surrounding rock and strengthening inspection and maintenance are put forward.

Key words: mixed well, acidic water, wellbore stability, prevention and control technology