Selman Er

Estimation of Cerchar abrasivity index of granitic rocks in Turkey by geological properties using regression analysis

The estimation of abrasivity on granitic rocks is very important in mechanical excavators. The mineralogical composition and physico-mechanical properties of the rock affects of abrasivity properties such as the type and size of the mineral grains and strength. Tool wear is an important parameter in hard rock tunnelling and mining applications that are highly affected by rock abrasivity. The estimation of the Cerchar abrasivity index (CAI) from geological properties is useful for excavation costs. For this purpose, CAI, chemical, petrographical, physical and mechanical tests were carried out on 12 granitic rocks taken from different regions of Turkey. The test results were analysed using the method of least squares regression. Multiple regression models having good correlation coefficients were obtained for the granitic rocks. The CAI tests were correlated with chemical compound and a weak relation was determined. The regression analysis was also repeated for petrographical, physical, and mechanical properties. Statistically meaningful correlations were determined between all geological properties and CAI. Then multiple regression analysis was applied to all geological properties to find the more significant relations. Results show that shore scleroscope hardness, water absorption, and the waveness average prove to be the best for estimating CAI of granitic rocks.

Numerical Modelling of Steep Slopes in Open Rock Quarries

The key question regarding steep rock slopes along rock quarries is their stability because a rock slope failure can have critical results. In this study, the aim is to investigate the areas with potential risk for jointed karstic limestones in a rock quarry. First, to determine rock mass properties, scan-line surveys were performed, and the major orientations of discontinuities were analyzed using stereographic projection. Then, the physicomechanical properties of the slope-forming rock were determined in the laboratory, and geomechanical properties of the rock mass were determined using an empirical failure criterion. Finally, the quarry slope stability was assessed in accordance with numerical modelling. According to the results obtained, the numerical modelling of steep rock slopes can be efficiently evaluated by using finite element method. Beside this, the presence of joints intersecting the main discontinuity sets, the filling materials of discontinuities resulting from weathering of limestone and surface deposits, surcharge load due to mine waste dumped on the slopes and excavation blasting during construction of quarry area play a key role when modelling the steep rock slopes by using finite element method.

Abrasiveness Properties at Different Temperatures of Basalt, Marble and Limestone in Turkey

Turkey is a bridge between Europe and Asia. There are numerous historical monuments in Turkey that were built by using natural stones. Due to the geographical features of Turkey, natural stones were exposed to different climatic conditions over time. Temperature and humidity changes have affected physical and mechanical properties of natural stones. The aim of this study is to investigate the physical and mechanical properties of basalt, marble and limestone, which are frequently used in historical buildings in Turkey, in saturated and dry state at different temperatures. For this purpose, basalt, marble and limestone samples were collected from their today’s quarries. The obtained samples were dried and saturated with water, cooled to −15 °C and heated to 105 °C. In every 5 min temperature values of samples were measured to reach up to room temperature (about 23 °C), thus their CERCHAR abrasiveness index were determined. According to the results obtained CERCHAR abrasiveness index increased when the temperature value exceeded 40 °C. In water saturated samples CERCHAR abrasiveness index didn’t change when the temperature value exceeded 30 °C.

Assessment of Excavatability, Abrasivity and Slope Stability in a Sandstone Quarry in Istanbul, Turkey

The Cebeci region is characterized by outcrops of Carboniferous sandstone, including diabase dykes. This region is very important area for aggregate production in Istanbul, Turkey. The aim of this study is to determine the engineering geological properties of sandstones to assess the excavatability, abrasivity and stability of cut slopes in a quarry site. Firstly, the sandstone samples were used to determine their petrographical and mineralogical characteristics. Then, physico-mechanical tests were performed on these samples. In order to determine rock mass properties, scan-line surveys were performed, and the major orientations of discontinuities were analyzed through the stereographic projection technique. Kinematical analyses were also made to determine the potential failures at the quarry site. According to the results obtained, excavatability is changed from easy ripping to hard ripping on sandstones; the carbonated sandstone is less abrasive than other sandstones. Based on the field studies and stability analyses of the cut slopes, optimum slope geometry and necessary support measures, such as wire mesh and rock fall barriers, are suggested.

Deterioration Types of Stones Used in Suleymaniye Mosque (Istanbul, Turkey)

Suleymaniye Mosque located in the historic peninsula of Istanbul, is one of the most important monument of classical Ottoman Architecture. Different types of natural stones having varied lithological characteristics were used in the mosque. Chemical composition, mineralogical, petrographic characteristics and external conditions such as atmospheric effects, earthquake and human impacts have deteriorated these stones over time. The aim of this study is to investigate different natural stones and their deterioration types used in Suleymaniye Mosque. According to the results obtained, generally different types of granites, marbles, limestones, pudding stones, porphyry, serpentinite were used in Suleymaniye Mosque. Detachment, material loss, biological colonization, discoloration and deposits have been determined as a deterioration types on these stones.

Rock Slope Stability Assessment of Limestone Quarry; An Example from Istanbul Cebeci Region, Turkey

The Cebeci Region is characterised by famous outcrops of Carboniferous Limestone which is mined out for aggregate production. The aim of this study is to investigate slope stability problems for heavily jointed karstic limestones in an aggregate quarry. Limestone quarries have turned into steep cliffs of bare rocks which threaten the safety of construction and have also negative influence on the aesthetics in the Cebeci Region. For this study, firstly, field studies were carried out involving detailed discontinuity surveys. Then, laboratory tests were conducted to determine physical, mechanical and elastic properties of the intact rock and shear strength parameters of the discontinuities for each different lithology. Kinematical analyses were performed to determine the potential kinematic failures and stability sites of the quarry. Also, finite element method analyses was carried out for the global stability of cut slopes with applying a number of different disturbance zones, parallel to the slope faces. According to the results of kinematic and numerical analysis, different types of failures are expected in different sites of quarry. Based on the field studies and stability analyses of the cut slopes, slope geometry optimization and necessary support measures such as wire mesh and rockfall barriers are suggested.

Assessment of Slope Stability Problems in an Open Pit Quarry; an Example from Istanbul Cebeci Region, Turkey

Rock slope stability is one of the important problems for open pit quarrying. This paper presents an instability assessment for jointed sandstone cut slopes in Cebeci Region, Istanbul, Turkey. In the quarry site, Carboniferous sandstones including diabase dykes are cropped out and these rocks are produced as aggregate. For this study, firstly, field study involving detailed discontinuity surveys were performed. Then, kinematical analyses were carried out to determine the potential failures at the quarry. According to the results of kinematic analysis, planar and wedge types of failures are expected in different parts of quarry. Based on the field studies and stability analyses of the cut slopes, optimum slope geometry and necessary support measures are suggested.