Analysis Of Surrounding Rock Permeability Characteristics And Prediction Of Water Inrush Risk In Deep Shaft Engineering Of Metal Mine

With the depletion of resources and the demand for strategic underground space in the country,the construction depth of shafts is increasing,and the complexity of the stratigraphic environment is also increasing,leading to an increase in the disaster.As an important corridor linking the ground and underground space,it is of great practical and strategic significance to study the safe and efficient construction of shafts for our economic and social construction and scientific development.The study is a part of the key topic "Basic theory and method of risk analysis for deep shaft construction project" of the National Key R&D Program of China "Key Technology of Deep Metal Mine Construction and Elevation".Taking the deep shaft of Shaling Gold Mine as the engineering background,on the basis of multi-field probing,the study on the variability of rock permeability properties was carried out based on the micro-fine characteristics of rocks.The water burst assessment approach and water surge control approach were proposed.The research results provide an important theoretical basis for deep shaft construction and disaster prevention and control.(1)Through hydraulic fracturing technology,acoustic measurement and core statistics method,pore water pressure test technology,the characteristics of 1600 m ground stress,formation integrity and pore water pressure in Shaling well area were analyzed,and the distribution laws of deep stress field,fracture field and seepage field were obtained.(2)Aiming at the uniformity characteristics of rock mineral distribution,the uniformity of rock mineral spatial distribution was analyzed from the aspects of mineral identification and stress deformation.The evaluation method of rock mineral spatial distribution uniformity was proposed based on CT scanning technology,DIC digital speckle technology and strain gauge deformation measurement technology.Based on the acoustic emission signal characteristics of strong and weak phase mineral damage during Brazilian splitting,the heterogeneity characteristics of rock were characterized by multiphase coefficient and spatial distribution uniformity.(3)Based on the rock heterogeneity evaluation method,the correlation between rock physical and mechanical properties and heterogeneity characteristics was studied.Through triaxial test under high confining pressure,hydraulic coupling test,CT scanning technology,acoustic emission technology and nuclear magnetic resonance test,the internal relations of deformation failure and crack propagation and heterogeneity characteristics in the process of rock stress were analyzed,and the permeability variability in the evolution process of deep rock damage was revealed.The identification method of acoustic emission signal for the critical failure of rock strong and weak phase minerals was proposed.(4)For the water inflow risk of shaft engineering surrounding rock caused by permeability variability of deep rock,the water inflow formula of shaft in different construction layers was established by constructing wellbore seepage model,and the prediction and control method of water inflow of deep shaft engineering surrounding rock was proposed.On the basis of considering the permeability variability of surrounding rock,the risk assessment method of water inrush in deep shaft of metal mine was established by comprehensively applying multi-source information such as structural fracture zone,fault fracture zone,water abundance,water inrush point,water conductivity and ground stress level.