Analysis of pressure surges under various flow patterns in the tunnel of an underwater rock plug blasting system using different transition process models

Abstract

The pressure surge at the moment of blasting seriously threatens the safety of pipeline structures and other buildings. This article established two numerical simulation models of the hydraulic transition process and water–air two-phase flow based on the one-dimensional transient flow theory and considering the actual flow characteristics of water and air. The hydraulic characteristics and blasting parameters of the blasting system were studied under two different conditions of the tunnel with and without the pressure flow. The observed parameters of an actual blasting engineering prototype verified the accuracy of the mathematical model. The maximum pressure of pressure blasting was 2.55 times as high as hydrostatic pressure. The maximum pressure of non-pressure blasting was 1.77 times as high as hydrostatic pressure. Pressure blasting impact was 2.17 times greater than nonpressure blasting. Discrepancies between actual and simulated data for gushing and overflow heights ranged from 9 to 14%. The model can provide a reference for blasting engineering on the simulation calculation of hydraulic characteristics such as impact pressure, overflow time, and overflow of the underwater rock plug blasting system. HIGHLIGHTS The simulation model of the hydraulic transient process in underwater rock plug blasting engineering was established by method of characteristics and water–air two-phase flow equation, respectively.; The observed parameters of an actual blasting prototype verified the accuracy of the mathematical model.; The blasting should be carried out in the nonfull flow in the tunnel when the impact pressure could meet the pressure standard of the system.;

Keywords

• impact pressure
• mathematical model
• rock plug blasting
• water–air two-phase flow
• water hammer pressure