Upper Red Formation sandstones under Brazilian and point load test conditions

This paper deals with the effect of lamination on the failure strength and fracture pattern of Upper Red Formation sandstones in southwest of Qom, Iran using Brazilian and point load tests. For this purpose, six blocks were taken from a part of this formation and have been drilled at different directions of lamination planes such as 0°, 30°, 45°, 60° and 90°.Although, the selected sandstones are seems similar but, the carried out test results and their failure patternsare different. The tensile strength, point load index and failure patterns in different inclination angles were determined for this group of sandstones. Also, the transitional angle of failurehas been determined for Brazilian and point load tests. The test results clearly indicated that failure strength and fractures pattern of laminated sandstones is a function of lamination inclination angle. Also, the results show there is a good correlation between strength and failure pattern of this group of sandstones under Brazilian and point load test conditions.