An experimental study of the influence of uniaxial load on flame jet drilling. (June 2018)

• Record Type: Journal Article
• Authors: Höser, D.; Meier, T.; Patru, A.; Kant, M.; Rudolf von Rohr, Ph.
• Is Part Of: International journal of rock mechanics and mining sciences. Volume 106(2018)
• Page Start: 311
• Page End: 318
• Publication Date: 2018-06
• Subjects: Grimsel Granodiorite -- Flame jet drilling -- Thermal spallation -- Uniaxial load; Rock mechanics -- Periodicals; Soil mechanics -- Periodicals; Mining engineering -- Periodicals; Roches, Mécanique des -- Périodiques; Sols, Mécanique des -- Périodiques; Technique minière -- Périodiques; 624.151305
• DOI: 10.1016/j.ijrmms.2018.04.007
• Languages: English
• ISSNs: 1365-1609

Abstract

Abstract: The performance of flame jet drilling on Grimsel Granodiorite cylindrical rock samples was experimentally investigated depending on applied uniaxial load. With a simple confining system for the rock samples, uniaxial load up to 47 MPa was tested in order to simulate the axial component of the stress tensor existing in a deep borehole. Provided that flame properties were unchanged, increasing the uniaxial load influenced the drilling positively. The experimental results were explained with numerically calculated stress profiles. It was concluded that tensile stresses below the heated surface increase with uniaxial load and additionally weaken the rock, which should improve the flame jet drilling with depth. Abstract : Graphical abstract: fx1 Abstract : Highlights: Influence of uniaxial load on flame jet drilling is experimentally investigated. Uniaxial load has a positive impact on flame jet drilling of hard rocks. Uniaxial load influences mostly the tensile stresses below the heated surface. Tensile stresses below the heated surface weaken the connections between grains. Results of the work contribute to the theory of thermal spallation mechanism.