حسام الدين اصفهاني

Investigation of fractures of rock masses and determination of their fracture resistance is one of the important engineering issues. Studying the fracture behavior of rocks with different geometries versus different loading modes is important in most engineering fields. By understanding the behavior of rock masses against crack growth, it is possible to predict the degradation or non-degradation conditions of rocks in geomechanical fields, Importance of this matter in two aspects of easier destruction of rocks and rock and mineral bedding for easier and more economical extraction of oil, easier and easier and cheaper cutting or preventing rock mass failure and consequently preventing damages such as collapse and leakage of oil wells, Destruction of idol structures Venny and the rocks on the side of the road. For various reasons such as climatic conditions and drilling operations, notches of different shapes may be formed in the rock masses. The U-shaped notch is one of the types of notches that causes severe stress concentration in the rock masses and makes their fracture conditions more critical. Therefore, it is necessary to reduce the loads of the U-shaped rock masses that are considered by engineers in the field of various materials including rock and minerals. The importance of rock breakage in industry can be used in road operations, tunneling, drilling of wells, hydraulic fracturing of oil wells. In order to break the cracks containing cracks and notches it is necessary to know the fracture toughness in the presence of cracks and notches. This parameter depends on various factors such as notch geometry and loading type (mode, mode, and combination mode or ...). Therefore, in the field of rock mechanics, the fracture toughness of materials should be predicted. This study investigates the fracture of white marble stone fragments with U-shaped notches. For this purpose, the effects of this type of notch on the fracture load of rock fragments are eva‎luated first by conducting experiments on Brazilian disk specimens with central U-shaped notch. Then the results of the experiments are compared and verified using two criteria of point stress and mean stress of the U-shaped notches. At the end of the comparison the theoretical and laboratory results show that the average stress criterion is better than the point stress criterion for estimating the fracture of U-shaped rock fragments.

شيار U شكل , نمونه ي آزمايشگاهي ديسك برزيلي , نيم ديسك برزيلي و SENB , شكست ترد , سنگ مرمر

U-shaped notch , Brazilian disk laboratory specimen , Brazilian half disk SENB , Brittle fracture , marble

Hesamedin Esfahani

Dr. Ayatollahi