Abstract: In order to break through the application limitations of liquid oxygen open-pit mines,the field application re search of liquid oxygen phase change fracturing technology was carried out for the complex and limited working conditions of small section seepage shaft.The sludge compensation cracking scheme suitable for small section seepage shaft is explored,and the PVC sealed liquid oxygen cracking pipe and its supporting sealing test are designed to form the construction technology of seepage water drainage and pore formation in restricted space.The throwing characteristics of rock mass,the forming quality of borehole wall and the distribution law of block size after liquid oxygen phase change fracturing are systematically analyzed.At the same time,based on the ground vibration monitoring,the vibration characteristics and safety effects are studied.The results show that the optimized liquid oxygen fracturing process can effectively adapt to the small section seepage shaft environment. The spatial differentiation of wellbore wall is formed by the combined action of liquid oxygen blasting energy distribution,stress propagation path and rock mass structure characteristics.The continuous high-pressure gas promotes the expansion and penetra tion of the rock mass,and then forms the distribution characteristics of 10-20 cm rock fragments.The quasi-static effect of the phase change process makes the near-field of the ground show the significant characteristics of medium-low frequency and low vibration velocity.The research provides technical reference and theoretical basis for the efficient rock breaking of liquid oxygen phase change fracturing technology under complex working conditions.

Key words: liquid oxygen blasting,seepage shaft,rock fragmentation,vibration monitoring