Assessing safety conditions in underground excavations after a methane-air mixture explosion

¹ Prydniprovska State Academy of Civil Engineering and Architecture, Department of Health and Safety, 24a Chernyshevskoho St., 49600 Dnipro, Ukraine
² Dnipro University of Technology, Department of Construction, Geotechnics and Geomechanics, 19 Yavornytskoho Ave., 49005 Dnipro, Ukraine
³ Dnipro University of Technology, Department of Hydrogeology and Engineering Geology, 19 Yavornytskoho Ave., 49005 Dnipro, Ukraine
⁴ Dnipro University of Technology, Department of General and Structural Geology, 19 Yavornytskoho Ave., 49005 Dnipro, Ukraine

^* Corresponding author: rudakov.d.v@nmu.one

Abstract

A technique for evaluation of shock wave impulse after a methane-air mixture explosion is elaborated. The numerical model developed in previous studies has been verified in the laboratory by using laser initiation of explosives and measuring the pressure impulses of explosion products on a ballistic pendulum. To evaluate the mechanical impulse the functional correlations between its magnitude, the swing angle, and the pendulum characteristics have been derived analytically. The reliability of experimental results is ensured by calibrating the sensor that measures the pendulum swing angle and estimating the impulse measurement errors caused by specifics of angle measurements by a digital voltmeter, pendulum axis friction, and the pauses between measurements. Testing the developed technique to evaluate the shock wave impact showed satisfactory consistency of experimental and theoretical results with the momentum deviation below 9%, which confirms model applicability and correct reproducibility of the shock wave propagation process.