Davood Fereidooni

In the present research, engineering properties of some sedimentary rock samples were measured to assess the correlations between P wave velocity and physical, index, and mechanical properties. The physical properties include dry and saturated unit weights, porosity, and water absorption. The index properties contain Schmidt rebound hardness and slake-durability index. The mechanical properties include uniaxial compressive strength, point load index, Brazilian tensile strength, and block punch strength. For this purpose, a comprehensive laboratory testing program was conducted after collecting 15 various sedimentary rock samples of four rock types from northwestern parts of Damghan, northern Iran. In the following, empirical equations were developed by using regression analyses between P wave velocity and the measured properties. The obtained results showed that all of the properties have strongly correlated to P wave velocity. Hereof, the relationships between P wave velocity and porosity and water absorption were inverse linear. But, P wave velocity has direct linear correlations with the other properties. Prepared contour maps indicated that P wave velocity is more affected by porosity of the rocks. The curves with the 45° line (y = x) were extracted for evaluating the validity degree of concluded empirical equations which approved approximately close relationships between P wave velocity and the measured properties. © 2018, Saudi Society for Geosciences.

Geotechnical characteristics were assessed to correlate physical, index, and mechanical properties of twelve sedimentary rock samples of four rock types collected from northern and northwestern parts of Damghan, northern Iran. Mineralogical and physical properties of the rocks were determined from prepared specimens in the laboratory after the field investigations. Also, the selected rock samples were subjected to index and mechanical tests including P-wave velocity, Schmidt rebound hardness, slake durability, point load, Brazilian, block punch, and uniaxial compressive strength. Mineralogical studies by thin section and X-Ray diffraction methods indicated that the selected rock samples with different textures are mainly composed of quartz and calcite. The studied rocks had low to high dry unit weight, low to medium porosity and low to very high P-wave velocity. The rocks were classified as durable and very durable based on the slake durability index. They were very strong to extremely strong in point load index, weak to moderate in block punch index, and weak to strong in uniaxial compressive strength. So they were classified in different strength categories. The obtained correlations between different rock properties from regression analyses indicated that specific gravity and unit weights are affected by mineral content while the other characteristics including water absorption, primary wave velocity, Schmidt rebound hardness, slake durability index, point load index, Brazilian tensile strength, and block punch strength are controlled by the porosity of the rocks. © 2018 by ASTM International.

The durability and geotechnical properties of 12 sedimentary rock samples collected from the Damghan area, Iran, were investigated. The rocks were subjected to mineralogical, physical, index and mechanical laboratory tests. Ten-cycle slake-durability tests were performed on the rocks using natural water and sulfuric acid solutions. The results of the mineralogical and X-ray diffraction studies indicated a change in the amount of soluble minerals after the slake-durability test in acidic solutions. A new test method, namely the accelerated weathering test (AWT), was conducted using a new apparatus designed and made for this purpose using natural and sulfuric acid solutions in ten wetting–drying cycles. Changes in the physical and index properties were observed in all tested samples after the fifth and tenth cycles of the test. A linear decrease in the values of the mechanical properties with decreasing pH of the solution and decreasing specimen size were observed in all samples under the test conditions. We present four new classification systems by which to classify the rocks after the AWT. Based on these results, the AWT can be used as a supplementary or even suitable independent test for evaluating the durability of rocks. © 2018 Springer-Verlag GmbH Germany, part of Springer Nature

Six travertine rock samples have been collected from different parts of Cheshmeh-Hafez quarry in northwest of Damghan, northern Iran. Physical and mechanical properties of the samples mean dry and saturated unit weights, specific gravity, porosity, water absorption, ultrasonic P wave velocity, Schmidt rebound hardness, point load index, Brazilian tensile strength, block punch index and uniaxial compressive strength have been determined according to the ISRM (in: Ulusay, Hudson (eds) Suggested methods prepared by the commission on testing methods, International Society for Rock Mechanics (ISRM), Kozan Offset, Ankara, 2007) standard in the laboratory. Also, slake-durability test was carried out up to ten cycles in different solutions. The used solutions were natural water with pH 7 of the region and sulfuric acidic solutions with pH of 5.5 and 4. Then empirical relationships by regression analyses were undertaken between the slake-durability indexes of all cycles of the test and measured physical and mechanical properties of the tested travertines. Regression analyses indicated that the relationships with correlation coefficients (R2) from 0.55 to 0.98 exist between slake-durability index and engineering properties of the rocks. The best and poor correlations were obtained between slake-durability index and specific gravity and block punch index, respectively. Results shown that in the first four wetting–drying cycles, the correlation coefficients between slake-durability index and physical properties of the rocks are rapidly increased, whiles the increasing rate of the correlation coefficients between slake-durability index and mechanical properties of the rocks is maximum in the first three cycles. Therefore, the first and second cycles of slake-durability test can’t able to present actual durability of the rocks. © 2017, Springer International Publishing AG.

The influences of mineral content and porosity on ultrasonic wave velocity were assessed for ten hornfelsic rocks collected from southern and western parts of the city of Hamedan, western Iran. Selected rock samples were subjected to mineralogical, physical, and index laboratory tests. The tested rocks contain quartz, feldspar, biotite, muscovite, garnet, sillimanite, kyanite, staurolite, graphite and other fine grained cryptocrystalline matrix materials. The values of dry unit weight of the rocks were high, but the values of porosity and water absorption were low. In the rocks, the values of dry unit weight are related to the presence of dense minerals such as garnet so not affected by porosity. The statistical relationships between mineral content, porosity and ultrasonic wave velocity indicated that the porosity is the most important factor influencing ultrasonic wave velocity of the studied rocks. The values of P-wave velocity of the rocks range from moderate to very high. Empirical equations, relevant to different parameters of the rocks, were proposed to determine the rocks’ essential characteristics such as primary and secondary wave velocities. Quality indexes (IQ) of the studied samples were determined based on P-wave velocities of them and their composing minerals and the samples were classified as non-fissured to moderately fissured rocks. Also, all tested samples are classified as slightly fissured rocks according to the ratio of S-wave to P-wave velocities. © 2018 Techno-Press, Ltd.

To assess the influence of discontinuities and clay minerals in their filling materials on the instability of rock slopes, seven rock slopes along the margin of Ganjnameh–Shahrestaneh Road, Hamedan Province, Western Iran were selected, and the physical and mechanical properties of their rocks and discontinuities were determined. By statistical studies of the discontinuities, rock slope stability analysis has been performed using kinematic and limit equilibrium methods so that safety factors for the rock slopes can be calculated. Also, sampling of filling materials and X-ray diffraction tests have been done to identify the clay minerals in the filling materials. The lithologies of the studied rock slopes are granite, diorite and hornfels. The presence of discontinuities and weakness planes with different orientations and clay minerals in filling materials of discontinuities are effective factors that cause plane, wedge and toppling failures in the rock slopes. Clay minerals as filling materials of discontinuities in the studied rock slope facilitate their instability by two different methods. First, absorption of water by infilling clay minerals causes the friction angle of discontinuity surfaces that leads to plane and wedge failures to be reduced. Second, water absorption causes the swelling of clay infilling minerals that leads to toppling failure. © 2017 Informa UK Limited, trading as Taylor & Francis Group.

Geotechnical characteristics and relationships between various physical and mechanical properties were assessed for eight types of hornfelsic rock collected from southern and southwestern parts of the city of Hamedan in western Iran. Rock samples were subjected to mineralogical, physical, index, and mechanical laboratory tests and found to contain quartz, feldspar, biotite, muscovite, garnet, sillimanite, kyanite, staurolite, graphite, and other fine-grained cryptocrystalline matrix materials. Samples had a porphyroblastic texture, and the mineral contents and physical properties influenced various rock characteristics. Some rock characteristics were affected by mineral content, while others were affected by porosity. Dry unit weight, primary and secondary wave velocities, and slake-durability index were noteworthy characteristics affected by mineral content, while porosity had the greatest influence on water absorption, Schmidt hardness, point load index, Brazilian tensile strength, and uniaxial compressive strength. Empirical equations describing the relationships between different rock parameters are proposed for determining the essential characteristics of rock, such as secondary wave velocity, slake-durability index, point load index, Brazilian tensile strength, and uniaxial compressive strength. On the basis of these properties, the studied rocks were classified as being strong or very strong. © 2016, Springer-Verlag Wien.

This paper explores the applicability of a modified Q classification system and its component parameters for analysis and conclusion of site investigation data to estimate rock slope stability. Based on the literature, Q classification system has high applicable potential for evaluation of rock mass quality. Therefore, in this study, it was used with RMR and SMR rock mass classification systems to assess stability or instability of different rock slopes along the Hamedan-Ganjnameh-Tuyserkan road, Hamedan province west of Iran. Furthermore, a modified rock mass classification system namely Slope Quality Rating (SQR) was proposed based on the correction of the Q classification parameters and calculating some new parameters such as dip and strike of discontinuities and the method of rock excavation or blasting. For this purpose, the SMR and RMR rock mass classifications were also needed. By measuring SQR for different rock slopes, it will be possible to measure Slope Mass Rating (SMR). © 2015, Universidad Nacional de Colombia. All rights reserved.

Analyses have been carried out considering the occurred earthquakes, geologic and seismotectonic conditions of the region covering a radius of 100 Km keeping Khoy as the center. The major seismic sources are small and large faults identified in the study area mostly directed in NW-SE. The MCE and PGA were measured based on both DSHA and PSHA approaches. The results of DSHA show that the MCE and PGA evaluated values are 6.8 Richter and 0.31g, which might be created by Chahar-Sotoon and Askar-Abad faults, respectively. The results of PSHA show that the MCE evaluated value is 6.1 Richter for a 0.64 probability in a 50- year period. Seismic hazard parameters have been evaluated considering the available earthquake data using Gutenberg-Richter relationship method. The 'a' and 'b' parameters were estimated 6.03 and 0.94, respectively. For earthquakes with magnitudes equal or greater than 6.1 Richter, the values of returning period (TR) and annual occurrence probability (PT) were obtained 112 and 0.009, respectively. The results obtained from two mentioned methods are matched to each other. Copyright © 2015, IGI Global.

In this research, different experimental techniques have been used to determine the strength of five types of anisotropic foliated rocks, selected from the Hamedan Province, west of Iran. For this purpose, after sample preparation and assessment of mineralogical and physical properties, selected samples were subjected to Cylindrical Punch, Point Load and Brazilian tests and their strengths were evaluated with respect to different angles between anisotropy planes and the major loading directions. Data analyses show that the types and amounts of minerals have an influence on the physical and mechanical properties of the tested anisotropic rocks. Porosity and water absorption also have a dominant control on the mechanical indices such as cylindrical punch index (CPI), point load index (Is(50)) and Brazilian tensile strength (BTS). On the basis of the test result, two empirical equations are proposed for calculating CPI and Is(50). Other empirical equations relating studied indices are also presented.