PSI - Issue 68

Sair Kahraman et al. / Procedia Structural Integrity 68 (2025) 722–726 Sair Kahraman and Abdalrahim A.M. Malakni / Structural Integrity Procedia 00 (2025) 000–000

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2.2. P-wave Velocity Tests The seismic measurements are non-destructive and can easily be carried out in the laboratory or in the field. For this reason, these methods are often used to characterize ground properties or estimate geo-resources deposits in various engineering applications such as mining, and petroleum engineering. They can also be used to determine the dynamic properties or some other properties of intact rocks in the laboratory. PUNDIT instrument was used in the sonic velocity tests (Fig. 2). PUNDIT has two piezoelectric (transmitter and reciever) transducers. The frequency of the transducers is 1 MHz. NQ (47.6 mm) size core samples obtained from the drilling tests were used in the P-wave velocity measurements Ultrasonic gel was used as a coupling agent to provide good coupling between core sample and transducers. The P-wave velocity values were calculated by dividing sample length by P-wave travel time, and listed in Table 1.

Fig. 2. P-wave velocity measurements.

3. Evaluation of the results PR values ranges from 1.46 cm/min to 6.00 cm/min for granite (Kozak). The P-wave velocity values vary in a very wide range from 3.48 km/s to 5.15 km/s. A wide range of variation means that the heterogeneity of the rock is high and microstructural elements such as microfractures and pores differ in the samples. For andesite (Kayseri), PR values ranges from 1.65 cm/min to 6.29 cm/min. The P-wave velocity values vary between 4.21 km/s and 4.88 km/s. PR values ranges from 1.52 cm/min to 6.75 cm/min for andesite (Gölbaşı). The P wave velocity values vary between 3.55 km/s and 3.83 km/s. For andesite (Kulu), PR values ranges from 1.461 cm/min to 7.32 cm/min. The P-wave velocity values vary between 3.67 km/s and 4.05 km/s. It can be said that the P-wave velocity values have a wide range for andesite (Kayseri), andesite (Gölbaşı), and andesite (Kulu). For diabase (Kayseri), PR values ranges from 1.66 cm/min to 1.70 cm/min. P wave velocity values vary in a narrow range between 5.45 km/h and 5.47 km/h. The narrow range means the rock is fairly homogeneous and microcracks are few. Drillability of rocks is affected by both operational parameters and rock properties. Operational parameters or controllable parameters are thrust, rotational speed, and flushing for rotary drilling. Rock properties, also called uncontrollable parameters, include strength, abrasiveness, mineralogical and geological properties. Since the drillability of rocks is affected by many factors, it should be evaluated by multiple regression analysis rather than simple regression analysis. Therefore, multiple regression analysis was carried out using the thrust, rotational speed, and P-wave velocity values to develop an estimation equation for penetration rate. A model with a very high correlation coefficient (r = 0.98) was derived. The model is as follows: = 1.67 + 1 10 !" − 0.03 # +0.05 (1)