Investigation of the effect of drillability and mechanical properties of rock on specific drilling energy

Over the years excavation machines are being widely used in underground and surface structures, tunneling works, mining and construction. The selection of suitable machinery for excavation and excavation purposes is very important. In this regard, drilling and blasting studies are carried out on the determination and extraction of natural resources such as water, oil or natural gas, in terms of mining; ground survey, injection, ground consolidation, drainage, dam, tunnel and so on. In many areas, drilling machines are widely used. Considering the drilling process, penetration rate and the amount of energy required to achieve progress are the two most commonly used parameters in the performance evaluation of drilling machines. In order to achieve the expected performance of drilling systems, these machines must be selected according to the rock properties. For this reason, it is very important to analyze the characteristics of the formation for the drillability performance evaluations.Specific energy and penetration rate parameters are commonly used in the oder of drilling performance evaluations. Specific energy determination is a commonly used factor as a measure of penetrability in mechanized drilling performance assessments. Since method varies according to the type of drilling and bit type, the type of rock can not be considered as a physical feature. However, it is used as the most important parameter used in estimation, comparison and optimum working conditions of drilling efficiency (production quantity). Specific energy is defined as the amount of energy required to break a certain volume from the rock (kWh/m3 or MJ/m3) or the amount of energy spent to create a new surface area in the rock during drilling. In order to determine the specific energy many methods are employed such as large and small-scale excavation sets, empirical approaches and field applications. Within the scope of this thesis study; the specific energy is defined as the specific drilling energy, considering the excavation method. Another important parameter used in drilling performance evaluations is the penetration rate which is defined as the hole length per unit time. In the context of this study; drilling were carried out on 16 rock types with sedimentary and magmatic origin by using the redesigned rotary hole drilling test set in ZBEU Mine Mechanization and Technology Laboratory. The core drilling machine used in the laboratory is compatible with rotary hole drilling systems and supported by suitable apparatus (torque, rotational speed, current and voltage, digital caliper, etc.). Thus, core drilling and drilling performance measurements can be made. The redesign of the set, the drilling performances of rotary drills, and today's highly complex machine settings (weight on bit, rotational speed, torque, power of the machine, etc.) are made. Experienced weight on bit and rotational speed / speed variables determine the operating conditions for the machine's operational function. Drilling operations were carried out in 4 different pressures (50, 70, 90 and 110 kg) and 3 different speed (210, 330 and 470 rpm), the drilling rotational torque, the actual rotational speed, the current, Voltage and power parameters are measured. Thus, the specific drilling energy is calculated mechanically and electrically, taking into account the most commonly used approaches for rotary drills.. During the studies, rock mechanics experiments were performed on the cores taken with diamond impregnated and core drilling bit. In the body of the study, physical (density) experiments, mechanical (compressive and tensile strength and deformation characteristics) characterizations, some index (DRI, CAI and ESD) calculations and determination of mineralogical properties of the rocks were performed separately by experiments. Thus, firstly, the effects of interchangeable machine parameters on specific drilling energy and penetration rate were investigated, and then the effects of physical, mechanical, index and mineralogical properties of the rocks on drilling performance were analyzed by statistical evaluation methods (correlation and regression). In this study, optimum working conditions have been obtained for each rock type in the current drilling conditions. In addition, DRI, as an index test method, was determined to explain the drilling performance parameters more significantly for the rocks used in the study. This thesis study primarily intended to focus on development of new formulas for estimating the specific drilling energy from rock properties and rotary drilling machine test set for mining and drilling operations.For the reliability of the models developed for drilling performance estimation, the number of samples used in the study should be increased and performance measurements of the drilling machines should be made and the relations between the laboratory studies and the measurements taken in the field should be examined.