Doctoral Dissertations


"In field excavation, cutting tools operate on rock surfaces damaged from previous tool pass, yet, average intact rock properties are often used in field project estimations. This can result in overestimation of excavation time and cost. The ability to accurately correlate the damaged rock properties to the excavation parameters means more reliable estimates of project completion time and costs, and hence improved the application of mechanical excavation technology to a wider range of civil and mining industries.

The purpose of this research was to better understand the relationship between rock cutting parameters and the excavated rock surface hardness during mechanical excavation. To do this, Roubidoux sandstone was subjected to linear cutting experiments using a radial drag pick at different cut spacing to depth of cut (s/d) ratios and the resultant forces and chips were analyzed. The rebound hardness of the excavated rock surface was subsequently measured using a rock-type Schmidt hammer.

Results and subsequent analysis indicated that the wide variability of Roubidoux sandstone coupled with the complex process of rock cutting prevented a clear determination of the relationship between the cutting forces and the excavated rock surface hardness.

2D stereonet models of the resultant force orientation data and estimates of the tool path deviation indicated that the cutting tool experienced significant deflection during cutting.

Finally, it was found that cutting geometry and excavated rock surface hardness contributed significantly to variations in the specific cutting energy"--Abstract, page iii.


Gertsch, Leslie S.

Committee Member(s)

Rogers, J. David
Maerz, Nobert H.
Anderson, Neil L. (Neil Lennart), 1954-
Samaranayake, V. A.


Geosciences and Geological and Petroleum Engineering

Degree Name

Ph. D. in Geological Engineering


Missouri University of Science and Technology. Rock Mechanics & Explosives Research Center


Missouri University of Science and Technology

Publication Date

Fall 2018


xxi, 360 pages

Note about bibliography

Includes bibliographic references (pages 345-359).


© 2018 Azupuri Germanus Ayerikujei Kaba, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11425

Electronic OCLC #