Exploration of key scientific and technological issues in liquid oxygen transient expansion to break rock

WANG Yanbing; PENG Huikang; FU Dairui; DING Baoshan; LIU Yuchen; WANG Dongchen; HUANG Zhehang; WANG Xiao

doi:10.13247/j.cnki.jcumt.20250417

Abstract：As a new rock breaking method,liquid oxygen transient expansion rock breaking technol-ogy shows significant potential in safety,vibration control and environmental protection perfor-mance.However,there are still some disputes on the energy release mechanism,safety boundary and process reliability.The reaction essence of the transient expansion process of liquid oxygen was systematically discussed,and the energy release mode of"combustion driven+phase transition dominated"was defined;A quantitative calculation method for the phase transition combustion ratio of liquid oxygen was proposed,which reveals that the vaporization expansion of liquid oxygen ac-counts for the main part of energy release;A test method for electrostatic sensitivity of liquid oxy-gen charge was proposed,the critical ignition energy of liquid oxygen charge under test conditions was determined,and it was proved that oil pollution would significantly improve its electrostatic sensitivity.Based on this,a method of eliminating electrostatic by equipotential grounding was pro-posed.Based on the above mechanism cognition,a tungsten wire mediated transient high tempera-ture ignition technology was developed to realize the intrinsic safety of the excitation source;The technology of subsection vibration reduction and detonation was invented according to the law of liq-uid oxygen phase change;The flying rock control method of top energy suppression and bottom en-ergy release and the flexible gradient plugging technology are proposed to effectively suppress flying rocks and reduce punching phenomenon;In addition,the mixed expansion of liquid oxygen and liq-uid nitrogen was explored to control the process of energy release.The field engineering application shows that the liquid oxygen transient expansion rock breaking technology has successfully realized the high-efficiency,low vibration and no flying rock breaking operation in the environment of urban foundation pit and earth rock mining,and verified the feasibility and engineering applicability of the technology.This study lays a theoretical and methodological foundation for the theoretical improve-ment,safety standardization and large-scale engineering application of liquid oxygen transient ex-pansion rock breaking technology.