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Abstract With the continuous development of underground engineering construction in China, it is particularly important to study the identification of structural plane characteristics of rock masses. In this study, three types of pseudo-rock specimens with structural plane interlayers were fabricated to analyze the patterns of drilling parameter changes in rock bodies with structural planes during the drilling process and to explore the characterization and identification methods of rock body structural planes. Gneiss, granite, and sandstone were used as rock materials, with gypsum mortar as the interlayer material for the structural planes in these three types of specimens. The indoor digital drilling equipment was utilized for conducting indoor digital drilling experiments. The variation patterns of drilling parameters in rock bodies with structural surfaces under different interlayer inclinations and thicknesses were analyzed. The relationship between the ratio of the change in rotational speed and drilling speed during the stable phase of the upper rock mass and the peak torque and peak drilling pressure has been established. The relationship between the structural plane inclination angle and the ratio of change in rotational speed and drilling speed has been determined. By utilizing the variation in these ratios, the impacts of the structural plane inclination angle and the thickness of the structural plane on the peak torque and peak drilling pressure have been elucidated. The research results provide a theoretical basis for the stability evaluation of rock masses with structural planes under drilling action.

This study aimed to evaluate various biomechanical parameters associated with the primary stability of Maestro and Due Cone implants placed in low-density artificial bones, prepared using high-speed drilling with irrigation and low-speed drilling without irrigation. The insertion torque (IT), removal torque (RT), and implant stability quotient (ISQ) values were recorded for Maestro and Due Cone implants placed in low-density polyurethane blocks (10 and 20 pounds per cubic foot (PCF) with and without a cortical layer) prepared using high-speed and low-speed with or without irrigation using a saline solution, respectively. A three-way ANOVA model and Tukey's post-hoc test were conducted, presenting data as means and standard deviations. P-values equal to or less than 0.05 were considered statistically significant. No statistically significant differences in IT, RT, and ISQ between drilling speeds were observed. However, Maestro implants exhibited lower IT and RT values after high- and low-speed drilling across almost all polyurethane blocks, significantly evident in the 20 PCF density block for IT and in the 20 PCF density block with the cortical layer for the RT with low-speed drilling (IT: 47.33 ± 10.02 Ncm and 16.00 ± 12.49 Ncm for Due Cone and Maestro implants, respectively, with p

Exploitation of polar resources and scientific research require efficient ice drilling technology. Thermal drilling is a common method for polar ice drilling, and is similar to the principle of ultrasonic assisted drilling; both are drilled by melting ice layers, but improving energy utilization has always been a challenge. In order to improve energy utilization and drilling efficiency, this paper proposes a method for ice drilling with ultrasonic frequency vibration. The mechanism of ultrasonic vibration drilling into ice was analyzed, the solid theoretical foundation for the application of ice melting efficiency under ultrasonic frequency vibration was determined and a series of indoor experiments were conducted. According to experimental data obtained, two conclusions were provided. First, different frequencies have distinct influence on power density, drilling speed and melting rate, and the optimum range excitation frequency for ultrasonic ice drilling is at least 30~32 kHz, under which the ice melting efficiency and drilling speed reached the peak value. Second, ultrasonic assisted drilling was verified to have the ability of improving the efficiency of ice breaking by comparing to thermal drilling under the same power density under 30 kHz. As an environmentally friendly and efficient drilling method, ultrasonic assisted ice drilling has great application prospects in the field of polar exploration. By using Ultrasonic assisted drilling, we demonstrate a strategy for a faster and more efficient drilling method, which is important for humankind.

Martian rocks contain crucial information about the genesis of Mars and the historical evolution of Martian climate change. Consequently, extracting and examining Martian rocks are pivotal in advancing our comprehensive understanding of the red planet. However, the current core drill string is prone to wear and tear, and the samples are susceptible to thermal denaturation. To address these challenges, we introduce two novel types of drill bits, the conical straight junk slot and the conical spiral junk slot, both employing impregnated diamond as the primary material. Comparative experiments were meticulously conducted to evaluate the influence of different junk configurations on drilling parameters, including speed, abrasion resistance, drilling force loading, and sample temperature rise. The findings unequivocally demonstrate the superior performance of the spiral junk slot. Furthermore, simulations were performed to examine the drilling process on basalt using a fixed configuration drill bit, validating the occurrence of the sample temperature rise. The research presented in this paper offers valuable programmatic references and essential data support for future Martian rock coring drilling missions.

Ice cores from polar zones could determine ice dating and biodiversity. Ice cores retrieved in hot-water ice-coring drilling partly melted owing to moderate drilling speed of annular drill head with many nozzles, which was largely depended on the heat transfer efficiency of jet to ice at borehole bottom. To obtain the higher drilling speed and ice cores of good quality, this paper explored the influence of nozzle parameters on the heat transfer efficiency of annular jet to bottom ice. Main nozzle parameters affecting the heat transfer efficiency were theoretically determined firstly. Then influence law of nozzle parameters on the heat transfer were estimated by theoretical calculation and numerical simulation. The result showed the heat transfer of annular jet to bottom ice was positively correlated with the nozzle flow and negatively relevant with the nozzle diameter, nozzle angle and nozzle quantity, which was further compared with the drilling speed value in experiment to confirm its correctness. The angle was proved to be the most influential parameter, when it increased from 0° to 30°, the drilling speed decreased 75%. The result can provided reference for designers on how to promote the drilling speed in hot-water ice-coring drilling and improve ice core quality.

The significance of micro-destructive testing, which can estimate the durability of reinforced concrete structures with minimal damage and high accuracy, in the investigation and diagnosis of reinforced concrete structures has been increasing. This study aims to evaluate the quality of the surface layer of concrete structures via a small-diameter drilling test, which is one of the micro-destructive tests developed to estimate the strength of concrete. Hence, it would be possible to evaluate the quality and strength of concrete simultaneously, which is very important. In this study, the influence of the bleeding amount which affects the surface quality of concrete on the drilling speed, was experimentally studied, considering the water-cement ratio and unit water content as experimental factors. The influence of bleeding on the drilling speed of the specimen surface was also investigated through measurements at the top and bottom surfaces. The following points were clarified from the experimental results and their analysis. (1) The drilling speed changes depending on the water-cement ratio and the unit water content. (2) The amount of bleeding affects the drilling speed; however the drilling speed is affected by the volume of the fine aggregate in the specimen. Therefore, (3) there is a possibility that it can be used for surface quality evaluation of concrete by examining in detail the method for calculating and correcting the drilling speed.

Bu çalışmada, altı farklı açık maden ocağında (4 adet kalker, 1 adet kil ve 1 adet feldspat ocağı) yapılan delme çalışmaları sırasında delici uç ve makine çalışma parametreleri (darbe miktarı, baskı kuvveti, hava basıncı ve dönme hızı) sabit tutularak delme hızları yerinde ölçülmüştür. Bu ocaklardan, laboratuvar deneyleri için şekilsiz bloklar ve delme işleminden çıkan kırıntılardan numuneler alınmıştır. Alınan kırıntı numunelerden pasa irilik katsayısı, blok numunelerden ise kayaçların fiziksel ve mekanik özellikleri belirlenmiştir. Ayrıca bu kaya birimlerinin delme oranı indeks (DRI) değerlerini belirlemek için Sievers minyatür delme deneyi ve kırılganlık deneyleri yapılmıştır. Çalışmalar sonunda, araziden alınan delme hızı verileri ile laboratuvarda yapılan deney sonuçları birlikte değerlendirilerek istatistiksel olarak irdelenmiştir. Arazi üzerinde ölçülen ilerleme hızları ile kayacın fiziksel ve mekanik özellikleri arasında anlamlı ilişkiler elde edilmiştir. Laboratuvar ortamında belirlenen delinebilirlik değerlerinin delme-patlatma çalışmalarında ilerleme hızının tahmin edilmesinde güvenilir bir şekilde kullanılabileceği belirlenmiştir.

Bu çalışmada, altı farklı açık maden ocağında (4 adet kalker, 1 adet kil ve 1 adet feldspat ocağı) yapılan delme çalışmaları sırasında delici uç ve makine çalışma parametreleri (darbe miktarı, baskı kuvveti, hava basıncı ve dönme hızı) sabit tutularak delme hızları yerinde ölçülmüştür. Bu ocaklardan, laboratuvar deneyleri için şekilsiz bloklar ve delme işleminden çıkan kırıntılardan numuneler alınmıştır. Alınan kırıntı numunelerden pasa irilik katsayısı, blok numunelerden ise kayaçların fiziksel ve mekanik özellikleri belirlenmiştir. Ayrıca bu kaya birimlerinin delme oranı indeks (DRI) değerlerini belirlemek için Sievers minyatür delme deneyi ve kırılganlık deneyleri yapılmıştır. Çalışmalar sonunda, araziden alınan delme hızı verileri ile laboratuvarda yapılan deney sonuçları birlikte değerlendirilerek istatistiksel olarak irdelenmiştir. Arazi üzerinde ölçülen ilerleme hızları ile kayacın fiziksel ve mekanik özellikleri arasında anlamlı ilişkiler elde edilmiştir. Laboratuvar ortamında belirlenen delinebilirlik değerlerinin delme-patlatma çalışmalarında ilerleme hızının tahmin edilmesinde güvenilir bir şekilde kullanılabileceği belirlenmiştir.

Bu çalışmada, altı farklı açık maden ocağında (4 adet kalker, 1 adet kil ve 1 adet feldspat ocağı) yapılan delme çalışmaları sırasında delici uç ve makine çalışma parametreleri (darbe miktarı, baskı kuvveti, hava basıncı ve dönme hızı) sabit tutularak delme hızları yerinde ölçülmüştür. Bu ocaklardan, laboratuvar deneyleri için şekilsiz bloklar ve delme işleminden çıkan kırıntılardan numuneler alınmıştır. Alınan kırıntı numunelerden pasa irilik katsayısı, blok numunelerden ise kayaçların fiziksel ve mekanik özellikleri belirlenmiştir. Ayrıca bu kaya birimlerinin delme oranı indeks (DRI) değerlerini belirlemek için Sievers minyatür delme deneyi ve kırılganlık deneyleri yapılmıştır. Çalışmalar sonunda, araziden alınan delme hızı verileri ile laboratuvarda yapılan deney sonuçları birlikte değerlendirilerek istatistiksel olarak irdelenmiştir. Arazi üzerinde ölçülen ilerleme hızları ile kayacın fiziksel ve mekanik özellikleri arasında anlamlı ilişkiler elde edilmiştir. Laboratuvar ortamında belirlenen delinebilirlik değerlerinin delme-patlatma çalışmalarında ilerleme hızının tahmin edilmesinde güvenilir bir şekilde kullanılabileceği belirlenmiştir.

The performed tests in this work include a wide range of rock masses of the Kopaonik massive of different strength (f = 2.3 - 16). Drilling was done with drill hammers VK-24 and RK-21 at optimum sharpening angle with different drill rod lengths (0.8, 1.2, 1.6, 2.4 and 3.2). Compressed air pressure is 0.60 MPa and diameter of drilling chisel d = 32 mm. The obtained results and analysis indicate that it is possible to determine the interdependence between the borehole length and drilling speed. The results of these tests are shown in Tables 1, 2, 3 and 4 and diagrams 1, 2, 3 and 4.

A survey done recently showed that almost 30 percent of the accidents occurred during oral implant surgery were concerned with the mandibular canal in the trabecular bone region and most of them were related to the drilling process. One of the reasons known is due to the clinicians' lack of knowledge and experience. In order to overcome the problem, through the educational approach, we proposed and developed a new system mainly for dental colleges' students, by focusing on drilling the mandibular trabecular bone. The system comes in the form of an oral implant surgery training simulator that enables student to sense the reaction force during drilling. The developed system was then evaluated by expert clinicians and dental college's students. A total of 8 clinicians and 24 students tested all three samples of drilling force database. The clinicians were asked to describe the drilling force based on a stiffness scale while the students are required to drill two samples first before drilling the third sample. They were asked to sketch the third samples based on the comparison of previous samples. Based on the evaluation done, it was found that the quantification of force sensed during drilling could be derived from the combination of drilling force and speed obtained through the relative value of comparison with the previous or accumulated experience of drilling. The results of this study also indicate that the oral implant surgery training simulator could help students learn the difference of drilling force sense dependent on the bone quality through repeated usage and practices.

The electrical discharge drilling could be applied in order to obtain cavities in workpieces made of materials difficult to be machined by classical machining methods. Distinct factors exert influence on the drilling speed. An experimental research was designed and developed by considering the depth of the cavity achieved by means of a tubular tool electrode. One used a machining scheme involving the achieving of the work movement by test piece to the tubular tool electrode clamped on the machine tool table. In this way, the influence exerted by the spurious electrical discharges facilitated by the presence in the work gap of the metallic particles detached from the two electrodes can be diminished. Empirical mathematical models were determined by mathematical processing of the experimental results and using specialized software. The empirical mathematical models proved a high influence exerted on the drilling speed by the peak current intensity.