Abstract
The demand for the usage of hydraulic rock breakers in excavating rock masses has increased recently for environmental and economic reasons. The conventional method (i.e., drill and blasting technique) has many restrictions due to environmental aspects. In this paper, we propose a methodology for the prediction of the performance of hydraulic rock breakers in the excavation of a rock mass. The case study area is located in Northwest Egypt on the shoreline of the Mediterranean Sea. Extensive site investigation was implemented using exploration boreholes showing that the majority of the site is limestone with lenses of sands. Based on the collected rock properties, mapping of both the rock quality (RQD) and the uniaxial compressive strength (UCS) for the rock mass was conducted. Such mapping of the mechanical properties helps in the zoning of a rock mass and grouping the similar rock zones of nearly matched properties. Due to economic and machinery availability concerns, this study focuses on very small, small, and medium capacity hydraulic breakers. For each type of rock breaker, calculations of the net breaking rate (NBR) are implemented for each group of the rock with similar properties. The challenge of this methodology is that the excavation of the rock mass shall be implemented in a very limited time frame (only one year ≈ 300 workdays). Therefore, two scenarios of light-duty and medium rock breakers are applied providing the number of machines required with specifications and working days. The first scenario is assigned to medium duty machines, while the second scenario concerns very small to small rock breakers. In general, such a sequence could be adopted for other cases with different rock mass properties, hydraulic breakers specifications and any desired time frame.
Highlights
A rock mass is composed of a combination of rock materials and a network of discontinuities
The zoning of the polygons by using the values of both the Uniaxial Compressive Strength (UCS) and the Rock Quality Designation (RQD) is created for the area of the study
The aim was to present a methodology that could help in the selection of the appropriate rock breaker specifications and their numbers, taking into account the geomechanical characteristics for the rock mass, the economic considerations and the time frame restrictions
Summary
A rock mass is composed of a combination of rock materials and a network of discontinuities. Rock masses vary in quality from very poor quality to excellent according to numerous factors, depending on the strength of the intact rock, the intensity and the condition of the discontinuities and the ground water conditions (Jaeger & Cook, 2007). Explosive and nonexplosive methods (i.e., the mechanical methods) are two different widely used methodologies to disintegrate a rock mass into smaller pieces (Ocak & Bilgin, 2010). The drill and blasting method is widely used for rock breaking due to its high efficiency and relative medium cost (Škrlec et al, 2014; Ocak and Bilgin, 2010; Tsiambaos and Saroglou, 2010).
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
