Tamer KORALAY, Sefer Beran ÇELİK, İbrahim ÇOBANOĞLU

Leeb sertliğinin kaya malzemelerin bazı fiziksel ve mekanik özelliklerinin tahmininde kullanımının araştırılması

Kaya malzemelerin tek eksenli sıkışma dayanımı (UCS) ve bazı fizikselözellikleri kaya mekaniği ve mühendisliğinde kullanılan çok önemli girdi parametreleridir. Fiziksel ve mekanik özelliklerin belirlendiğideneylerde, belirli şekil ve boyuttaki standart örneklerkullanılmaktadır. Ancak, örnek hazırlamanın güç olduğu koşullarda budeğerlerin belirlenmesi güçleşmekte ve bu sorunun aşılması amacıyladoğrudan olmayan deney yöntemlerinden tahminleri tercihedilmektedir. Kaya malzemelerin özelliklerinin tahmininde kullanılanen yaygın parametrelerden birisi de yüzey sertliğidir. Bu çalışmakapsamında kaya malzemeler üzerinde kullanımı yaygınlaşmayabaşlayan ve Schmidt çekicine göre, çok daha düşük bir çarpmaenerjisine sahip olan Leeb sertlik cihazı ile elde edilen sertlikdeğerlerinin (HL) seçilen ignimbirit, traverten ve siyenit türü kayalarınbazı fiziksel ve mekanik özelliklerinin tahmininde kullanılabilirliğiaraştırılmıştır. Öncelikle örneklerinin petrografik ve temel fizikselözellikleri incelenmiş, daha sonra tüm örneklerin HL değerleriölçülmüştür. Kuru (dry) ve doygun (sat) birim hacim ağırlıklar, görünürporozite (nA), su emme (wS), ultrases hızı (VP) değerleri ile HL değerlerikorele edilmiş ve ilgili eşitliklerle sunulmuştur ayrıca HL değerlerindenUCS değerlerinin tahmini için bir eşitlik önerilmiştir. Çalışmakapsamında, örneklerin boy/çap oranının (L/D) HL ölçümleri üzerineetkisi de araştırılmıştır. Sonuç olarak 50 mm çaplı ve minimum 1.5 L/Doranlı örnekler üzerinde HL değerlerinin sağlıklı olarak ölçülebileceğiönerilmiştir.

Investigation of the use of Leeb hardness in the estimation of some physicaland mechanical properties of rock materials

Uniaxial compressive strength (UCS) and some physical properties of rock materials are very important input parameters used in rock mechanics and engineering. Samples with standard shape and dimension are used in physical and mechanical tests. However, it is difficult to determine the UCS values in case of difficult sample preparation conditions. To overcome this limitation prediction of UCS values from indirect test methods is preferred. One of the most common parameters used to predict the UCS values of rock materials is surface hardness. In this study, the usability of hardness values (HL) of selected ignimbrite, travertine and syenite rocks in the prediction of some physical and mechanical properties were investigated by using the Leeb hardness test which has much lower impact energy than the Schmidt hardness hammer has. Firstly, petrographic and some physical and mechanical properties of the samples were determined and then the HLmeasurements of all samples were taken. Test results were correlated and correlation equations for dry (dry) and saturated (sat) unit weights, apparent porosity (nA), water absorption (wS), sonic wave velocity (VP) were presented and prediction equation of UCS from HL measurements were proposed. In the context of the study, the effect of L/D ratio on HLmeasurements were also investigated and minimum length to diameter(L/D) ratio of 1.5 on samples with 50 mm in diameter was suggested for consistent HL measurements.

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