Simulation of dynamic fracture of the borehole bottom taking into consideration stress concentrator

Authors

DOI:

https://doi.org/10.15587/1729-4061.2017.101444

Keywords:

borehole, subdrilling, stress concentrator, drilling and blasting operations, finite element method, AUTODYN

Abstract

In the problems of high-speed impact, penetration, explosion, aerohydroelasticity and other non-stationary processes accompanied by high strain rates, program complexes using an explicit method for solving equations of continuum mechanics are widely used. At present, the most promising method for modeling and calculating such problems is the finite element method.

Explosive or mechanical creation of initial cracks in the bottom part of the borehole makes it possible to reduce significantly amount of the load necessary for fracture contributing to a more effective development of the shoulder foot. This leads to a reduction in subdrilling. Presence of the subdrilling increases drilling costs by 20...30 %, worsens crushing of the upper part of the rock body and increases fracturing of the upper part of the next shoulder. However, this method requires additional costs and complicates the process of charging wells. One of the possible ways to simplify this method is to form the borehole bottom with a minimum rounding radius of the zone of interface between the borehole bottom and the wall.

It was established that the value of the relative radius of rounding between the bottom and the walls of the borehole significantly affects the character of the crack formation in the lower layers. It is possible to overcome the problem of obtaining rск→0 by creating borehole structures with a shock wave concentrator at the borehole bottom. The conical surface of these devices will ensure making the angle between the borehole bottom and the wall less than 90°.

Author Biographies

Viktor Vorobyov, Kremenchuk Mykhailo Ostrohradskyi National University Pershotravneva str., 20, Kremenchuk, Ukraine, 39600

Doctor of Technical Sciences, ProfessorDepartment of Mechanics and Materials Science

Marina Pomazan, Kremenchuk Mykhailo Ostrohradskyi National University Pershotravneva str., 20, Kremenchuk, Ukraine, 39600

PhD

Department of Geodesy, Organization of Land Use and cadastre 

Sergii Shlyk, Kremenchuk Mykhailo Ostrohradskyi National University Pershotravneva str., 20, Kremenchuk, Ukraine, 39600

PhD, Associate Professor

Department of Manufacturing Engineering 

Larysa Vorobyova, Kremenchuk Mykhailo Ostrohradskyi National University Pershotravneva str., 20, Kremenchuk, Ukraine, 39600

PhD, Associate Professor

Department of Economics

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Published

2017-06-08

How to Cite

Vorobyov, V., Pomazan, M., Shlyk, S., & Vorobyova, L. (2017). Simulation of dynamic fracture of the borehole bottom taking into consideration stress concentrator. Eastern-European Journal of Enterprise Technologies, 3(1 (87), 53–62. https://doi.org/10.15587/1729-4061.2017.101444

Issue

Vol. 3 No. 1 (87) (2017): Engineering technological systems

Section

Engineering technological systems

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Copyright (c) 2017 Viktor Vorobyov, Marina Pomazan, Sergii Shlyk, Larysa Vorobyova

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